Copyright: ® Roberta M. Cobb


Help Contents
Contents

Xpress XRAID

May Release

Product Update Information

Current Product Codes

Board History

Software History

Orderable Spare Parts List

General Product Information

Approved Manufacturer List for SIMMs

Readme Files

Frequently Asked Questions

Errata

Disk Array Application Note

Introduction

RAID Descriptions

Selecting a RAID Mode

Getting the Most out of RAID

XRAID4 RAID Controller

RAID Installation

XRAID4 Configuration


May Release

This help file was compiled on May 31, 95

•	Updated Board and Software histories

•	Added README.TXT file (for DOS Driver)

•	Added UPGRADE.ME file (instructions for upgrading BIOS and Firmware)

•	There is no Banyan certification for XRAID4.

•	Added index


Current Product Codes

XRAID4	2 channel RAID SCSI-2 disk controller, 4MB cache.  Includes PBA, cable, and manual.


Board History

616047-002	Current PBA


Software History

XRAID4 − Class II

Current Implementation Date: Implemented 5/95

Incorporate new firmware ver 2.14 and BIOS ver 1.19.

Incorporate new Windows NT, OS/2, SCO UNIX, and Netware driver floppy disks into software kit.

ECO Number 5521925


Orderable Spare Parts List

There are no orderable spare parts for this board-level product.

614122-002	Manual (order from Product Literature)


Approved Manufacturer List for SIMMs

The following 9 bit (30 pin) SIMM modules have been tested for compatibility with the 1/2 Channel DAC960 Controller, testing performed by Mylex Corporation.

Hyundai	4MB Module 4MB x4 x3, 70 ns

Mitsubishi	4MB Module 4MB x1 x9, 70 ns

Motorola	4MB Module 4MB x1 x9, 70 ns

Hyundai	1MB Module 1MB x1 x3, 70ns

Hyundai	1MB Module 1MB x1 x9, 70ns

Mitsubishi	1MB Module 1MB x1 x9, 70ns

OKI	1MB Module 1MB x1 x3, 70ns


Readme Files

UPGRADE.ME

READAC.ME

README.TXT (for DOS Driver)

README.NW3

README.NW4

README.OS2

README.SCO

README.WNT


UPGRADE.ME

DAC960/DAC960E/DAC960P  UPGRADE

1/2/3-Channel DAC960/DAC960E/ DAC960P

This release of firmware ver 2.14 / 2.19 and BIOS version 1.19 are supported

on all the EISA DAC960 and PCI DAC960P controllers. New features have been

added to the controller to improve the performance.

** WARNING : IT IS ALWAYS RECOMMENDED TO BACKUP YOUR DATA BEFORE ANY

     UPGRADE IS PERFORMED, UNEXPECTED LOSS OF DATA IS POSSIBLE

     IF AN OLDER VERSIONS OF PROGRAM ( DAC960CF.EXE OR DAC32CF.EXE )

     IS BEING USED, THAT IS NOT COMPATIBLE TO THE NEW DACCF.EXE.

     YOU MUST BACKUP YOUR DATA AND RECREATE YOUR SYSTEM DRIVE.

     ALL DATA IN THE HARD DISK WILL BE DESTROYED .

UPGRADE:

People interested in upgrading to the new firmware and BIOS should do the

following.

Note:   The upgrade will involve loss of data if a stripe size other than 8K

is to be used. Even if the stripe size is left as 8K, following

procedure is to be strictly followed, if data loss is to be averted.

1.      Save the existing controller configuration to a floppy by using the

DACCF.EXE  TOOLS/BACKUP CONFIG options.

2.      If you are upgrading EISA DAC960 which has firmware version

1.58 or below, upgrade the firmware using the firmware flash utility

DACFL.EXE and appropriate firmware file. Make sure all the upgrade

program run from floppy.

A> DACFL FW5.214   (for DAC960-5 controller, used 4 x9 30 pin simm)

A> DACFL FW3.214   (for DAC960-3 controller, use 4 x9 30 pin simm)

A> DACFL FW2.214   (for DAC960-1/2 controller, used 4 x9 30pin simm)

A> DACFL FWA.214   (for DAC960E\LB\ASIC 123Ch controllers, use

single x 36 72 pin simm)

3.      If you are upgrading PCI DAC or EISA DAC960 which has firmware version

1.99 or above, Upgrade the firmware using the firmware flash utility

DAC960FL.EXE and appropriate firmware file. Make sure all the upgrade

program run from floppy.

A> DAC960FL FW5.214   (for DAC960-5 controller, used 4 x9 30 pin simm)

A> DAC960FL FW3.214   (for DAC960-3 controller, use 4 x9 30 pin simm)

A> DAC960FL FW2.214   (for DAC960-1/2 controller, used 4 x9 30pin simm)

A> DAC960FL FWA.214   (for DAC960E\LB\ASIC 123Ch controllers, use

single x 36 72 pin simm)

A> DAC960FL FWP.219    (for DAC960P controllers)

   For DAC960P, firmware and BIOS programmed at the same time

(Please note that flashing the wrong firmware binary will prevent the

controller from functioning and will require a new EPROM from the

factory.)

4.      For EISA controller, Boot the system and EISA configure the board,

make sure the controller BIOS is enable in EISA configuration.

5.      Disable the ALL Adapter BIOS shadowing in system CMOS setup, clean

boot the system from floppy and upgrade the BIOS using the BIOS

flash utility.

 ** for EISA only, ALL version **

 A> BIOSWRT  DACBIOS.119

6.      Run the new DACCF.EXE ( ver 3.02 ), included in this floppy. If the

stripe size is to be left intact, restore the backed up configuration

using the TOOLS/RESTORE CONFIG option. Reboot the system and proceed

normally.

7.      If stripe size is to be changed, select the Advanced option from the

main menu of  DACCF and save the configuration. Reboot the system and

proceed to install the your Operating system.( All data on disk will

be destroy ).

Known Problems:

For the DAC960E, if 2 MB cache is used with write back, then 64K or 32K

stripe size can't be used.


READAC.ME

                      DAC960 DISK ARRAY

                     (1/2/3 CHANNEL DAC960P)

                           (9/20/94)

This Release of the Configuration and Utility diskette contains

the following files:

READDAC.ME       : This file containing general information about this

                   diskette.

\DACCFG\DACCF.EXE: This is the DAC960P configuration utility.  Instructions

   on its use are detailed in the DAC960P Disk Array

   Controller User's Manual.

\DOS\README.DOC    This file contains important information and instructions

   about using the DOS drivers for DAC960 and the DACMON utility.

\DOS\DACDRVR.SYS : This is the DAC960P DOS driver.

\DOS\DACMON.EXE  : This is the DAC960 administration utility for use

                   with DOS driver.

\DOS\DAFCDA.SYS  : This is the CDROM driver that works with the ASPI

                   driver, ASPIDAC.SYS.

\DOS\ASPIDAC.SYS : This is the ASPI driver for DAC960 to support non

                   disk devices under DOS. This version of driver does

                   not work with memory managers like Windows 3.1,

                   QEMM etc..

#Note# The following file will be available at a later date:

\DACCFG\DACD.EXE : This is the DAC960P diagnostics utility.  This file is

   Used by the DACCF configuration utility when selecting

   the diagnostics option in the main menu.

This release supports DAC960P Firmware ver 1.99 and above. The 1.99

version of firmware has undergone functionality testing under

Netware 3.1X, Windows NT 3.1 and Windows 3.1 with various disk

array configurations on the controller.

The DAC960P is designed to support cache memory sizes of 2MB, 4MB, 8MB,

16MB and 32MB using standard 72 pin (36 bit) SIMM modules or cache memory

sizes of 4MB and 8MB with EDRAMs (from Ramtron).

Precautions, Known Limitations :

 - Under DOS, when using system drives with Write Back cache, make it

   a point to wait for 15 seconds after the last operation, before

   rebooting or powering off the drive/system. This is to make sure

   data in the cache is written to the disk, before the system is

   rebooted.

 - Two or more drives cannot be rebuilt at the same time.

 - ASPIDAC.SYS : This ASPI driver will only work under DOS without any

   memory managers.

 - The "10) Diagnostics" option in the DACCF main menu is a feature that

   has yet to be implemented.  If you choose this, you will get a message

   indicating that going further will have unpredictable results.  Simply

   hit <Esc> and return to the main menu.


README.TXT (for DOS Driver)

 DAC960P DOS Driver Documentation :

  Version 2.00

  September 21, 1994

  The users are advised to go through this README document before

  starting to use the DOS driver.

  The DAC960 DOS driver directory contains the following files :

  FILE NAME	SIZE	DATE	VERSION	DESCRIPTION

  DACDRVR.SYS	4551	8/3/94	2.00	DOS driver for DAC960

  DACMON.EXE	70744	6/4/93	1.11	Administration Utility for DAC960

under DOS

  ASPIDAC.SYS	10088  10/21/93 1.04	DOS ASPI driver for DAC960

  DAFCDA.SYS	4696	6/16/93	1.00	DOS CD-ROM driver for DAC960

  DAC960P BIOS :

  The BIOS provides access for up to 8 system drives per DAC960P, under

  DOS ver 5.0 and above. The total DOS partition size is limited to

  1024 cylinders (BIOS limit) and hence it does not make sense to have

  a system drive of more than 2048 MB, if it is used only for DOS. The

  maximum size of any DOS partition cannot be more than 1023 cylinders

  or 2046MB.

  DOS Driver :

  The BIOS on the DAC960P is usable only under the real mode of the

  operating system. In order to use the DAC960P under memory managers

  like Windows, QEMM etc., a DOS driver needs to be used. The

  DOS driver, DACDRVR.SYS supports only disk drives. The total DOS

  partition size on the DAC960P is limited to 2048 MB, even when the

  DOS driver is used.

  ASPI Driver :

  If non disk devices are connected, use the ASPI driver ASPIDAC.SYS

  under DOS, to access these devices. Note that the ASPI driver works

  only WITHOUT any memory managers like Windows 3.1, QEMM  etc.

  The ASPIDAC.SYS works in conjunction with the DOS driver, DACDRVR.SYS.

  CDROM Driver :

  Also a CDROM driver DAFCDA.SYS is included, to allow CDROM access under

  DOS, using a MSCDEX driver. The DAFCDA.SYS works in conjunction with the

  ASPI driver, ASPIDAC.SYS.

  Installation :

  If DAC960 is the only disk controller in the system, use DOS

  "fdisk" to create a DOS partition and use DOS "format c: /s "

  to high level format the DOS partition. Boot from the DAC960

  disk.

  Copy the driver file, DACDRVR.SYS from the DAC960P DOS driver

  diskette to the root directory of the boot disk. Optionally,

  copy the driver file ASPIDAC.SYS (ASPI driver) and DAFCDA.SYS

  (CDROM driver) to the root directory of the boot disk.

  The DAC960P DOS, ASPI and CDROM drivers are installed with the help

  of CONFIG.SYS.

  The following lines are put in the CONFIG.SYS file to install the

  DAC960P DOS, ASPI and CDROM driver.

  DEVICE={DRIVE}:DACDRVR.SYS

  DEVICE={DRIVE}:ASPIDAC.SYS

  DEVICE={DRIVE}:DAFCDA.SYS

  In order to use the CDROM as a logical drive under DOS, the autoexec.bat

  file needs to load the MSCDEX driver as follows:

  {DRIVE}:MSCDEX /V /M:10 /D:MSCD001

  Note :   MSCDEX  is  available  in  DOS 6.0  or  supplied by CDROM

  manufacturers.

  All the above statements need to be put before any line loading the

  memory manager, like himem.sys, qemm.sys, emm386.exe etc.

  DACDRVR.SYS, ASPIDAC.SYS and DAFCDA.SYS should always be installed in

  real memory and never in high, expanded or extended memory.

  If using another disk controller with DAC960, make sure all the

  drivers associated with the other disk controller are loaded before

  the DAC960 DOS driver.

  Copy the DAC960P Monitor utility DACMON.EXE from the DAC960 DOS

  driver diskette to the hard disk.

  This completes the installation of the DAC960 DOS driver.

  Known Bugs/Limitations :

  ASPIDAC.SYS and DAFCDA.SYS should not be used in Windows 3.x, QEMM

  etc..

  None of these drivers can be loaded in upper or high memory.

  ASPIDAC.SYS will behave unpredicatbly, under an "installation

  abort" condition or on a controller that has no drives connected to

  it. Do not use ASPIDAC.SYS when installation abort error is reported by

  BIOS.

  DACMON Utility :

  This is an administrative utility for the DAC960 DOS user. This

  utility can be invoked under DOS or the DOS screen of Windows. Once

  invoked by entering DACADM <CR>, it comes up with a main menu screen

  similar to the one shown below.

  _________________Disk Array Monitor V 1.00________________________

  |                                                                |

  | ______________ ___________  ___________  ____________ ________ |

  | | Select DAC | | Standby |  | Rebuild |  | Chng Dev | | Quit | |

  | |____________| |_________|  |_________|  |__________| |______| |

  |                                                                |

  | ___________________________________________                    |

  | |                                         |                    |

  | |_________________________________________|                    |

  |                                                                |

  |           ----------- Target-------->      ___System Drive___  |

  |                                            | 0> ONLN RAID-7 |  |

  |  Ch-0>    ONL     ---     ONL     ---      | 1> CRIT RAID-5 |  |

  |                                            | 2> CRIT RAID-1 |  |

  |  Ch-1>    ---     DDD     ---     ---      |                |  |

  |                                            |                |  |

  |  Ch-2>    ---     ---     STB     ---      |                |  |

  |                                            |                |  |

  |  Ch-3>    ---     ---     ---     ---      |________________|  |

  |                                                                |

  |  Ch-4>    ---     ---     ---     ONL                          |

  |                                                                |

  |                                                                |

  |     _______________<Message Log>____________________           |

  |     |                                              |           |

  |     |                                              |           |

  |     |                                              |           |

  |     |______________________________________________|           |

  |                                                                |

  |________________________________________________________DAC #1__|

               Fig 1.0 : Disk Array Monitor (Main Menu)

  Main Menu :

  The top portion of the screen lists the 5 options namely Select DAC,

  Standby, Rebuild, Chng Dev and Quit.

  The rectangular box below this displays details about the option

  currently selected.

  Below that a matrix of drives connected on various channels of the

  selected adapters are displayed. The left most column corresponds

  to SCSI ID 0 and SCSI ID is incremented for every column. The

  letters ONL, STB, DDD and --- are displayed for an Online,

  Standby, Dead and not present disk drive respectively.

  Below this is the message log box, where the description about

  the drive failures, status of standby or manual rebuilds etc.

  are displayed for the selected adapter.

  The last line displays the number of the currently selected DAC960.

  Use the left and right arrow keys to select one of the five options.

  displayed on the top of the screen. The selected option box is

  highlighted and also the box below the option box displays a

  brief description about the option. Hit the ENTER key to select the

  highlighted option.

  Select DAC :

  Once the Select DAC option is selected, a window pops up displaying

  the possible four DAC960s. Use the arrow keys to highlight the

  appropriate DAC960 that needs to be administered and hit Enter key

  to select it. The arrow keys can be used to select only a DAC960

  controller present in the system. The main menu is displayed now and

  the currently selected DAC960's number is displayed on the last line

  of the main menu.

  Standby :

  This option is used to make a drive ( that has replaced a dead drive )

  standby. Once this option is selected, the cursor jumps to the drive

  matrix area and allows the selection of the drive ( to be made standby )

  using the arrow keys. Select a drive and hit Enter to make the

  selected drive standby. The controller will try to start the drive

  and on successful starting of the drive will make the drive a

  standby drive. Note only disk drives that are not part of any pack

  can be made standby drives. Hit Escape key to return to main menu.

  Rebuild :

  This option is used to rebuild a drive that was killed ( shown as

  DDD on the matrix area ) by the DAC960. Before this option is

  invoked, the killed drive has to be replaced by a properly working

  drive. Once this option is selected, the cursor jumps to the drive

  matrix area and allows the selection of the drive (to be rebuild)

  using the arrow keys. Select a drive to be rebuild and hit Enter to

  start the rebuild. The selected drive is then started, optionally

  allowed to low level format and rebuild. While the rebuild is going

  on, the Rebuild status is graphically displayed on a horizontal bar

  for every system drive that needs to be rebuild. Also the progress

  and completion status of the rebuild is indicated in the message log

  area of the main menu. On successful completion of Rebuild, the

  drive is made Online and indicated in the matrix by words ONL.

  Chng Dev :

  This option is used to quiet a SCSI channel on the DAC960, so

  that the dead drive on that SCSI channel can be replaced online

  for rebuilding. Once this option is selected, the cursor jumps

  to the matrix area and allows selection of the channel to be

  stopped using the arrow keys. Select a channel ( where the

  dead drive needs to be replaced ) and hit Enter to stop the

  activities on the channel. At this point of time disconnect the

  power cable to the dead drive and disconnect the SCSI cable on

  the dead drive. Plug in a new good drive with the same SCSI ID,

  connect the SCSI cable and power cable to it. Press a key to

  resume the channel activities.

  Note : The channel activities will automatically be restarted in

  about 30 seconds of stopping the channel (without updating the

  screen). Hence the drive removal and replacement needs to be

  done in less than 30 seconds. The removal and replacement can also

  be done in two stages, stopping the channel before removal and

  replacement.

  Quit :

  This option is used to terminate the program.


README.NW3

                  DAC960 DISK ARRAY CONTROLLER

                      Combined PCI & EISA

                    Netware 3.0X Driver (Rev 3.05)

                       December 16, 1994

   This is the new release of the Netware drivers and utilities for both

   PCI and EISA DAC960 controllers.

 Prerequisites :

  The EISA DAC960 Controller should have a Firmware version of 2.14 or later

  and a BIOS version of 1.18 or later.

  The PCI DAC960P should have firmware version of 2.14 or later and a

  BIOS version of 1.01 or later.

   This driver supports disk and non disk devices like CDROM and

   tape drives.

   The following files in the NW_31X directory of the DAC960 Software Kit

   diskette constitute the Netware 3.1X drivers and utilities :

FILENAME	DATE	SIZE	VERSION	DESCRIPTION

README.NW3 :  	12/16/94	This file, containing general

information about this release.

DAC960.DSK :	12/12/94 13212  3.05	DAC960 driver for Netware 3.1X.

ASPIDAC3.DSK:	10/31/94  4593  3.01 	DAC960 ASPI driver for Netware 3.1X.

DACADM.NLM :	12/8/94  172279 3.01	DAC960 administration utility for

                                 	Netware 3.1X.

DACMON.NLM: 	12/13/94  65274	3.05    DAC960 monitoring utility for

         	Netware 3.1X.

DACBRDGE.NLM	9/28/94    3109 1.00	Bridge utility to support Red Alert

notification software

INSTALLATION :

   Full installation instructions are available in the DAC

   Software Kit User's Manual

The following features have been added to the driver and utilities:

-  The driver and administration utility now allows the addition of new

   drives without powering down the server.  The new drives can be added

   as "Hot Spares" or configured to add additional space.  This includes

   the ability to add and configure additional RAID drives.

-  The driver and administration utility now allows the user to stop and

   start a channel while the server remains on line.

-  The driver now issues a "flush" command during the Novell shutdown.

-  DACMON.EXE now displays proper statistics on the Screen.

-  DACMON.EXE now has DAC960S Support in the display.

-  DACMON.EXE now has 5 Channel Support.

-  DACADM.EXE now displays Tape and CDROM devices.

Precautions , Known Limitations and Bugs (Netware 3.1X and 4.01) :

 - DACADM Utility : When the RAID Consistency option of this utility is

   used while DOS is still in server memory and any "load" command is

   executed on the server console, the server screen clears and appears

   to lock up. Also all workstations receive network errors, but the disk

   LEDs remain ON and continue the consistency check. The screen ultimately

   reappears after the consistency check has completed. To avoid this long

   temporary lock up remove DOS from server memory by using the

   "remove dos" command from the server console before running the RAID

   consistency check.

 - If 8 System drives are already defined, don't add packs or define

   more system drives.

 - Don't use IRQ 15 under Netware on any DAC960. On some motherboards,

   under light to medium activity, the server displays a

   "Secondary Interrupt controller detected a lost interrupt" message and

   subsequently abends the server.


README.NW4

                  DAC960 DISK ARRAY CONTROLLER

                      Combined PCI & EISA

                    Netware 3.0X Driver (Rev 3.05)

                       December 16, 1994

   This is the new release of the Netware drivers and utilities for both

   PCI and EISA DAC960 controllers.

Prerequisites :

  The EISA DAC960 Controller should have a Firmware version of 2.14 or later

  and a BIOS version of 1.18 or later.

  The PCI DAC960P should have firmware version of 2.14 or later and a

  BIOS version of 1.01 or later.

  This driver supports disk and non disk devices like CDROM and

  tape drives.

 The following files in the NW_40X directory of the DAC960 Software Kit

 diskette constitute the Netware 4.X drivers and utilities :

FILENAME	DATE	SIZE	VERSION	DESCRIPTION

README.NW4 :  	12/16/94	This file, containing general

information about this release.

DACNET4.DSK :	12/12/94 13184  3.05	DAC960 driver for Netware 4.X.

ASPIDAC4.DSK:	10/31/94  4592  3.01 	DAC960 ASPI driver for Netware 4.X

                                 	Auto-loads CLIB.NLM

DACADM.NLM :	12/8/94 172279  3.01	DAC960 administration utility for

                                 	Netware

DACMON.NLM: 	12/13/94 65274  3.05	DAC960 monitoring utility for Netware

DACNET4.DDI:	12/13/94  1046	1.00	DAC960 information file used by

Netware during installation.

DACBRDGE.NLM	9/28/94   1159  1.00	Bridge utility to support Red Alert

notification software

INSTALLATION :

   Full installation instructions are available in the DAC

   Software Kit User's Manual

The following features have been added to the driver and utilities:

-  The driver and administration utility now allows the addition of new

   drives without powering down the server.  The new drives can be added

   as "Hot Spares" or configured to add additional space.  This includes

   the ability to add and configure additional RAID drives.

-  The driver and administration utility now allows the user to stop and

   start a channel while the server remains on line.

-  The driver now issues a "flush" command during the Novell shutdown.

-  DACMON.EXE now displays proper statistics on the Screen.

-  DACMON.EXE now has DAC960S Support in the display.

-  DACMON.EXE now has 5 Channel  Support.

-  DACADM now displays Tape and CDROM devices.

-  OS/2 for Netware is supported with this release

Precautions , Known Limitations and Bugs (Netware 3.1X and 4.01) :

 - DACADM Utility : When the RAID Consistency option of this utility is

   used while DOS is still in server memory and any "load" command is

   executed on the server console, the server screen clears and appears

   to lock up. Also all workstations receive network errors, but the disk

   LEDs remain ON and continue the consistency check. The screen ultimately

   reappears after the consistency check has completed. To avoid this long

   temporary lock up remove DOS from server memory by using the

   "remove dos" command from the server console before running the RAID

   consistency check.

 - If 8 System drives are already defined, don't add packs or define

   more system drives.

 - Don't use IRQ 15 under Netware on any DAC960. On some motherboards,

   under light to medium activity, the server displays a

   "Secondary Interrupt controller detected a lost interrupt" message and

   subsequently abends the server.


README.OS2

  DAC960

  Combined PCI/EISA OS/2 2.x Driver

  Version 3.0

  December 16, 1994

  Users are advised to read through this README document before starting

  to use this OS/2 2.x driver.

  Prerequisites :

  The EISA DAC960 Controller should have a Firmware version of 2.14 or later

  and a BIOS version of 1.18 or later.

  The PCI DAC960P should have firmware version of 2.14 or later and a

  BIOS version of 1.01 or later.

  The DAC960 OS/2 2.x driver diskette contains the following files :

  FILENAME	SIZE	DATE	VERSION	DESCRIPTION

  README.OS2:	This file.

  DAC960.ADD:	16212	11/8/94  3.01	The DAC960 Driver for OS/2 2.x

  DACADM.EXE:	96256	10/7/94	 3.01	The administration utility for the

        	DAC960 controller

  DACADM.HLP:	6667	9/16/94    	The DAC960 administration utility

help file.

 Installation :  All installation instructions are available in the

   DAC Software Kit User's Manual

  Test Report :

  The OS/2 Driver for the DAC960 has been tested with up to 4 adapters

  on OS/2 2.1 and 2.11.  Tape drives and CD-ROM drives have been tested.

  Both edge and level, shared and unshared interrupts have been tested.

  Under OS/2 2.1 HPFS partitions above 2048MB have been tested on the

  system drives other than 1.

  Known Bugs / Limitations :

  DACADM.EXE     : CDROM / TAPE drives are not indicated on the

                   DACADM screens. However the device information window

                   displays proper device ID strings.

  DAC960 Driver  : The first OS/2 partition / system drive should be

                   less than  2046 MB. Subsequent partition / system

                   drives may be upto 32GB.

  DAC960 Driver  : Supports only the OS2SCSI interface. It does not support

                   the ASPI interface.


README.SCO

NOTES ON SCO UNIX 3.2.4.2 (ODT 3.0) DRIVERS

Date:	December 16, 1994

Included in the DAC960 Software Kit 1.01 is the SCO UNIX BTLD Version 3.01

diskette.

Instructions on installation of the SCO drivers and utilities are included

in the DAC960 Software Kit's Users Manual.

The following are important notes on the installation:

SUPPORT OF SCO UNIX 3.2.4.2 (ODT 3.0)

The current release of the Mylex SCO Unix Driver ver. 3.00 supports SCO

Unix 3.2.4.2 or ODT 3.0 only.  It will fail to install on the earlier SCO

versions.

UPGRADING FROM MYLEX SCO UNIX DRIVER VER2.X TO 3.X

Because the new SCO Unix Driver 3.00 is an "mscsi" device driver, and the

previous versions were not, it is necessary to completely reinstall SCO

Unix in order to perform an upgrade.  This of course requires backing up

old files and  performing a fresh SCO Unix installation.  This change in

device driver type was necessary to (1) eliminate the need for 2

interrupts,  (2) utilize SCO's built in SCSI procedures, (3) make it

possible for the user to define the sizes of system drives 5 through 8.

INSTALLING THE DAC960 WITH AN ADDITIONAL ADAPTEC, OR OTHER MSCSI DEVICE

SCO UNIX doesn't support installation using two "mscsi" compliant drivers.

This means that to install SCO UNIX on a drive connected to a DAC960,

the CD-ROM or Tape must be connected to a DAC960. In addition, the Adaptec

driver (built into SCO Unix ) must be disabled during installation if

there is an Adaptec board in the system. To do this, type the following

at the boot prompt:

boot: defbootstr disable=ad link=mdac

Note that, "ad" is the driver for Adaptec 154x.  If the system is equipped

with some other Adaptec model,  or some other mscsi supported Host Bus

Adapter, replace "ad" with that driver name.  ( "mdac" is the driver name

for DAC960).

After the installation process, the secondary controller can be added

using "mkdev" procedures of SCO.

To install SCO on a drive connected to an Adaptec HBA when there is a

DAC960 also in the system, the tape or CD-ROM must be connected to an

Adaptec and the DAC960 must not be linked during installation.  The DAC960

can be added after installation using the "btldinstall" command as

described in the Mylex SCO Unix driver installation procedures.

MAXIMUM NUMBER OF SYSTEM DRIVES WITH THE DAC960

The DAC960 supports up to 8 system drives under SCO Unix.  The .scsi file

in SCO Unix 3.2.4.2 sees the system drives as having SCSI ID's 0 through 7.

If you are going to use a non-disk device on the DAC960, this can result in

 the loss of the ability to create all 8 system drives.  This can be

overcome through the use of Logical Unit Numbers (LUN's) at the shared

ID's.

A non-disk device must have LUN 0 in order to be seen by SCO Unix.  So the

system drive at a shared address should be set to another LUN, such as 1.

This is accomplished routinely when you run "mkdev hd".  If you want to

add a system drive at the same ID as an existing non-disk device, select

the driver number and SCSI ID the same as the non-disk device, and select

1 for the LUN.

In general, if there is any possibility that you will be using

approximately 8 system drives and some non-disk devices, set the LUN's

on system drives 1 through 7 to 1 (system drive 0 must have LUN 0).

Then you will be able to add 6 non-disk devices without affecting the

number of system drives.


README.WNT

  Mylex Corporation

  December 16, 1994

  3.01  Release of the Combined PCI and EISA Windows NT 3.5 Driver for the

  DAC960 Controller

  Users are advised to go through this document

  before starting to use the Windows NT driver.

  Prerequisites :

  The EISA DAC960 Controller should have a Firmware version of 2.14 or later

  and a BIOS version of 1.18 or later.

  The PCI DAC960P should have firmware version of 2.14 or later and a

  BIOS version of 1.01 or later.

  The \NT_35 subdirectory of the DAC960 Software Kit diskette contains

  the following files :

  FILENAME	SIZE	DATE	VERSION 	DESCRIPTION

  DAC960NT.SYS   15840	11/10/94 3.01	The main driver file for Windows NT.

  DACMON.EXE	137752	10/21/94 3.01   The DAC960 monitor utility for

monitoring the DAC960's Activity.

  DACADM.EXE	147596	10/21/94 3.01   The DAC960 administration utility.

  DAC_SCSI          13	8/24/93	Driver identification file, required

for driver installation.

  OEMSETUP.INF	 13958	9/20/94	 3.00   This file is required for adding

additional DAC960's on a system

installed with NT.

  DISK1 	     2	6/10/94	Utility file

  DISK2	     2	6/10/94         Utility file

  README.WNT    	This file.

In the root directory of this diskette:

  TXTSETUP.OEM 	  1727	9/20/94	3.0     Setup file required for installation.

  Installation :

  To install this new driver on a new system or an existing DAC960 based

  NT system, follow the instructions in the DAC960 Software Installation

  Manual.

  The 3.01 version of the Windows NT 3.5 includes the following features

  over the 3.00 version:

-  Added support for the Mylex Micro-Channel controllers

-  Added support for Mylex 5 Channel controllers

-  Fixes a problem that Tape drives had with rewinding

  Test Report :

  This version of the Windows NT 3.5 Driver for the DAC960 has been tested

  with up to 4 adapters per system. It was tested with both edge and level

  interrupts, NTFS partitions greater than 2048MB on system drives other

  than the primary drive, and with non disk devices such as tape drives

  and CD-ROMs.

  Known Bugs / Limitations :

  NT Driver  : The first NT partition/system drive must be less than

  2024 MB. Subsequent partition/system drives may be more than 2024MB.

  Running Multiple sessions of the DACADM or DACMON is not supported


Frequently Asked Questions

Is XRAID4 Banyan Certified?

I'm using Netware and my server abends, what's wrong?

I'm using a Seagate drive and I always get an error message on cold boot.  What's wrong?


Is XRAID4 Banyan Certified?

No.  There are no plans to obtain Banyan certification for this product.


I'm using Netware and my server abends, what's wrong?

Don't use IRQ 15 under Netware on any DAC960. On some motherboards, under light to medium activity, the server displays a "Secondary Interrupt controller detected a lost interrupt" message and subsequently abends the server.


I'm using a Seagate drive and I always get an error message on cold boot.  What's wrong?

Problem:

A system that works fine on Seagate 32550N and others but will always fail from cold boot with the error:

SCSI Device at Chn n, Tgt n not responding!

where n is the first device on the system.   The ECU does not allow boot spin-up of first drive(s) and delayed spin of others, you can only choose to have all delayed or all spin up immediately.  The same error occurs when drive jumper settings are used to delay spin-up.

Resolution:

New Seagate Firmware fixed this problem.  Seagate will have it on their BBS.

(d-542)


Errata

Windows NT V3.5 in Dual Processing Mode

Netware

Monitor reports incorrect read and write performance


Windows NT V3.5 in Dual Processing Mode

Windows NT V3.5 WON'T WORK in dual processing mode with the old XRAID BIOS, Firmware and drivers. You must upgrade to the new XRAID drivers (BIOS 1.18 and FW 2.14) for dual processing to work with NT V3.5.

The symptom is that Windows NT hangs at the blue screen just after it rebuilt the kernel and was rebooting into the graphical part of the install.


Netware

Problem:  After loading the new drivers the server abended immediately after loading the new DAC monitor (DACMON).

Loading DACMON after MOUNT ALL works.

        LOAD DAC960

        MOUNT ALL

        LOAD DACMON

   But the following abends the server.

        LOAD DAC960

        LOAD DACMON

        MOUNT ALL


Monitor reports incorrect read and write performance

The new monitor reports incorrect read and write KB/sec performance.  An 1190 MB file copies in 18 minutes which is a through put of 66 MB/minute or 1.1 MB/sec.  Stated in the terms reported by the DAC monitor this is, reads 1.1 MB/sec. and writes 1.1 MB/sec.  Through out the time of the copy the new DAC monitor reports reads at  ~550 KB/sec. and writes at  ~550 KB/sec.  The old monitor reports reads at ~1150 KB/sec. and writes at ~1150 KB/sec.


Introduction

The rapid development of hardware and software technology over the last few years has led to many systems moving from mainframes to PC-based networks. This testifies to the increased performance of today's PC microprocessors and the improved reliability of PC platforms and networks. With the advent of advanced Client/Server solutions, there are now massive databases supporting mission critical applications on low cost personal computers. System manufacturers working on new PC designs are constantly looking to incorporate the next piece of high-tech, high-speed architecture that was previously available only on mainframes.

Three main technology areas being copied from mainframes into today's personal computers are:

•	The microprocessor.  Intel continues to lead the way in this arena. System designers today have a family of Intel processors promising compatibility with inexpensive and easily portable applications − including a new building block capable of 100 MIPs, the Pentium™ microprocessor.

•	More capable networks and hubs. These vary from intelligent hubs, that can automatically reroute failed lines, to high speed FDDI networks promising 100 Mbits/second on shielded twisted pair connections or the even higher performing ATM networks promising over 4Gbits/second transfers.

•	The storage subsystem. This is undisputedly the weakest (and slowest) area of today's high performance servers. The main culprits are the disk drives and the disk controllers. Since most of the new applications rely on heavy transaction processing on massive databases, disk activity has gone through the roof. While PC processing power has improved greatly, disk performance and reliability has not kept pace.

Related Topics:

Reliability and Data Availability

Solutions

The Xpress RAID Solution

Why to use the Xpress RAID solution:

The Value of RAID: A Case Study


Reliability and Data Availability

A computer's ability to operate over a period of time without failure is called system reliability and depends on the reliability of the individual components. Hard disks are the weakest link in today's systems, because the devices are the only mechanical member of an otherwise all- electronic system. The disk drive contains a mass of moving, mechanical parts operating at high speed. The question is not whether the hard drive will fail, but when a hard drive will fail.

When any other component fails, it is simply replaced. When a hard disk fails, replacement is just the first step. The data on the disk may be worth thousands of dollars and timely recovery could be critical to a company's survival. If the data cannot be restored, any information created since the last backup will be lost forever. Sensible network managers incorporate rigorous backup procedures, but the loss of the system for even a few hours can be disastrous in some cases. The ability to access data even after a disk failure is called data availability.

Data availability and system reliability are crucial to today's business users.


Solutions

The need for instant data availability and total system reliability have led computer makers to come up with some interesting solutions to the I/O bottleneck and its inherent unreliability.

Parallel Transfer Drives

One of the first techniques to improve data transfer rates from the drives was to use multiple heads. This type of drive is known as a Single Large Expensive Drive (SLED) and is ideal for applications where large sequential files are being manipulated. However, such drives do not tackle the fundamental reliability problems and would not perform satisfactorily in transaction processing environments where the emphasis is on a large number of small requests being serviced.

Striping

The striping technique divides data across many drives and improves data transfer rates and total disk transaction times. Such systems are good for transaction processing, but suffer from poor reliability because the system is only as reliable as the weakest individual drive.

Mirroring

Mirroring (or shadowing) is a technique where the data is written simultaneously to a pair of drives. These systems offer excellent reliability and have very good transaction processing results because the work can be carried out by either drive in the pair. The penalty paid is that two drives must be purchased to get the capacity of only one.

JBOD

A slick way of saying "Just a Bunch Of Drives." The idea behind JBOD is to spread the data across many drives using one (or more) disk controllers. Such systems are very similar to striped systems, but are very difficult to use efficiently as the load is never spread evenly across all the drives.

Disk Arrays

Disk Arrays are a group of drives acting as a single unit. They can be implemented in many ways and, depending on the implementation, can provide many of the benefits of the other drive combinations described. These benefits include:

•	 Better I/O subsystem performance

•	 Higher system reliability

•	 Better data availability

•	 Lower cost per megabyte


The Xpress RAID Solution

High I/O Performance	Disk arrays can offer higher performance than ordinary disks.
High data transfer rates	Intel's solution can transfer data at up to 33Mbytes per second.
High data availability	Disk arrays offer continuously available data.
Continuous service	Xpress Server uptime is measured as greater than 99.98%
Cost effectiveness	Disk arrays cost less than comparable redundant systems. Typically they should cost 2/3 of a similar disk mirrored system.
Industry standard solutions	Our solution is based on the industry standard SCSI-2 interface.
Different RAID solutions for different environments	Intel's RAID product allows you to configure it for RAID Levels 0, 1, 5 or 6.
Online reconstruction of data	Intel's solution allows you to reconstruct your data in the background while your system is running.
Disk subsystem expansion	Our solution offers two SCSI channels. You may use one channel exclusively or split the drives across both channels. Either implemenation allows you to add more drives later.
Least-cost upgradeability	Intel's solution offers you the ability to upgrade the on-board cache and you may increase the number of drives when you need to.
Minimal use of floor space	Intel's solution is highly integrated and fits inside the Xpress Desk-side/MX, eliminating the need for an external expansion chassis.


Why to use the Xpress RAID solution:

The cost of Disk Arrays is more than non-array storage.	The cost of data loss and the resulting loss in business is far greater than the initial cost of setting up an array
Special software is needed to run a disk array.	The Intel solution transparently handles all RAID data handling
RAID limits storage capacity	With today's 3.5" drive technology you can have up to eight 2.2 GB drives. This gives you 15.4 GB of safe RAID 5 storage.
RAID solutions are slower than other systems	RAID systems on the Xpress Servers can be configured as RAID Level 5 for transaction processing or RAID 0 for pure performance


The Value of RAID: A Case Study

Like everything else in life, people don't see the real value of a product until they've suffered some pain.

Recently, the EIS department of a major corporation suffered a fatal disk crash. The EIS managers had backups and thought they were prepared for a catastrophe. Unfortunately, the failure occured during working hours. As a result, the electronic mail system was down while the hard disk was replaced and the database rebuilt. This process took five hours of downtime.

It was the loss of the database and not the loss of the system that cost the company a great deal of money. Here's an analysis of the costs incurred:

2	hours to replace the machine

+	3	hours to rebuild the database

5	hours of  system downtime

5	hours

x	100	users

500	worker-hours

500	number of worker-hours

x	100	dollars per hour

$50,000	Lost

As the figures reveal, a RAID system would have cost much less.


RAID Descriptions

Several levels of Redundant Arrays of Inexpensive Disks (RAID) were defined by a University of California research team:

•	RAID-0 Data striping without parity

•	RAID-1 Mirrored disks

•	RAID-2 Parallel disks using hamming code

•	RAID-3 Parallel disks with parity

•	RAID-4 Independent drives with parity on a dedicated disk

•	RAID-5 Independent drives with parity distributed across disks

•	RAID-6 Mirrored striped disks

Related Topics:

RAID  LEVEL 0: Data Striping without Parity

RAID  LEVEL 1: Mirrored Disks

RAID  LEVEL 2: Parallel Array Using Hamming Code

RAID  LEVEL 3: Parallel Array Using Parity

RAID  LEVEL 4: Independent Actuator Array Using Parity

RAID  LEVEL 5: Independent Actuator Array, Distributed Parity

RAID  LEVEL 6: Mirrored Striped Disks


RAID  LEVEL 0: Data Striping without Parity

This is an array of disk drives that allows simultaneous, independent data operations on each drive in the array. Data is striped by blocks across all of the disks. A block is a selected number of sectors. Striping the data ensures that each drive is used equally. Since each I/O operation involves only a single drive, a multi-tasking operating system can issue independent transactions for each drive. Striping the data increases the I/O throughput and the number of transactions able to take place in a given amount of time. The I/O throughput rate increases proportionally as the number of drives in the array increases. Parity (or ECC) is not used in this RAID level. In fact, the term RAID does not really apply because there is no redundancy and no way to recover from data loss.

Characteristics

•	Data is striped across all drives.

•	Drive spindles need not be synchronized.

•	Number of drives and performance is scalable.

Error Recovery

•  No Parity information stored on the drives

•  Data recovery is limited to the drive electronics

•  The only way to recover the data is to use system backups

Advantages

•	High I/O transaction rate.

•	Multiple simultaneous seeks improve speed

•	Transparent to system software

•	Faster in smaller server applications

•	Load is balanced across all drives

Disadvantages

•  No parity or redundancy

•  No increase in data availability

•  Decreased MTTF


RAID  LEVEL 1: Mirrored Disks

RAID Level 1 pairs each primary data disk with a companion disk. Any time data is written to a disk, it is also written to its twin. This process is transparent to the operating system and the end user. Mirroring has been used for years in critical applications and offers very good performance. Read performance is increased because either drive in the mirrored pair can service the request (i.e.; while one drive is servicing a read, the other drive can service a second read). In a heavily loaded system, twice as many read requests may be processed in a given time period. However, a write request requires twice the processing time.  Overall performance depends on the ratio of reads to writes. Mirrored pairs enjoy a very high MTTF because the failure of one drive does not affect system operation. However, they are costly because the user  has to buy twice as many drives to support the technique.

Error Recovery

•  Error recovery is through the use of the mirrored drive.

Characteristics

•  Data is duplicated on mirrored drives

•  Drive spindles are not synchronized

•  Performance is a function of the number of drives

•  Load is not balanced across the drives

Advantages

•  Maximum data availability

•  Transparent to system software

•  No performance penalty after a drive failure

Disadvantages

•  100% cost overhead

•  Requires twice the space and power


RAID  LEVEL 2: Parallel Array Using Hamming Code

This is an array in which each drive holds a bit of information. Additional drives hold error correcting and detecting bits of data. The technique is very similar to that used for storing information within a disk drive. As the array grows, there is a proportionally smaller penalty for the error recovery characteristic (i.e., storing 16 bits of data requires 5 bits of ECC, while storing 32 bits of data needs only 7 bits of ECC). These systems provide excellent data transfer rates with the ability to detect and correct single bit/drive failures.

Error Recovery

•  Errors are corrected by recalculating the failed bit from the ECC data stored in the array

Characteristics

•  Data is spread  across all the drives

•  Drive spindles must be synchronized

•  The larger the array, the more efficient the storage capacity of the array

•  Data  is corrected by the controller on the fly

Advantages

•  High data transfer rate.

•  High data security, as data on any single drive is useless

•  High data availability

•  Transparent to system software

Disadvantages

•  Poor for transaction processing

•  High cost for small arrays

•  Special drives/drivers/operating systems required


RAID  LEVEL 3: Parallel Array Using Parity

This array allows parallel transfer of data from all of the drives. This means that a read or write to/from the array simultaneously involves all of the drives, resulting in improved data transfer rates. Any number of data drives can be used with a parity drive to form an array acting as one unit. Data is spread across the drives in the array at the byte level with one drive holding the parity byte. The information on the parity drive allows data to be reconstructed in the event of any single drive failure. The parity drive contains the exclusive-OR data of all data on the drives in the array, allowing data to be reconstructed. But this implementation can be difficult because the size of all logical block writes must be equal to the number of data drives multiplied by the drive sector size. This requirement may cause integration problems for various operating systems with limited ability to modify the standard block size.

Allowing the array to remain on-line when a drive has failed greatly increases data availability.

Error Recovery

•  Error recovery is through the use of parity information stored on dedicated drive

•  Performed automatically by the disk controller

Characteristics

•  Data is spread across all the drives in bytes

•  Drive spindles must be synchronized

•  Number of drives and performance is scalable

•  Suited for large file transfers

•  Suitable for workstations that require fast sequential access to a single large file

Advantages

•  Highest data transfer rate of any RAID level

•  Increased reliability and data availability

Disadvantages

•  Poor performance for small block transfers

•  Slower than RAID-5 for transaction processing

•  Unsuitable for a multi-tasking system

•  May create integration problems [Logical block write size = (number of drives) * (drive sector size)]


RAID  LEVEL 4: Independent Actuator Array Using Parity

This array is like RAID 0. Data is striped across the disks, but there is an additional dedicated drive used for parity. This array uses the parity drive to reconstruct data if a drive fails. Striping the data ensures that each drive is used equally. Since each read transaction involves only a single drive, a multi-tasking operating system can issue independent reads to multiple drives. Striping the data increases the read throughput and the number of reads that can take place in a given amount of time. The read throughput rate increases proportionally as the number of drives in the array increases. However, write performance is reduced by having a dedicated parity drive. This is because each write operation requires four disk operations: (1) Read old data, (2) Read old parity, (3) Write new data, and (4) Write new parity. This causes the parity drive to become a bottleneck. Although each write cycle can possibly go to a different drive, parity information has to go to the parity drive.

Error Recovery

•  Error recovery is  through the use of parity information stored on dedicated drive

•  Done automatically by the disk controller

Characteristics

•  Data is spread across all the drives in blocks

•  Drive spindles are not synchronized

•  Dedicated parity drive

•  Independent actuators

•  Number of drives and performance is scalable

Advantages

•  Good performance for reads during transaction processing

•  Multiple actuator seeks improve speed

•  Increased reliability and data availability

•  Transparent to system software

Disadvantages

•  Poor performance for write operations

•  Slower than RAID-5 for transaction processing

•  Parity disk bottleneck

•  Performance degradation during data reconstruction


RAID  LEVEL 5: Independent Actuator Array, Distributed Parity

This technique has all of the benefits of RAID 4, but does not suffer from the parity drive bottleneck. RAID 5 achieves this by spreading parity information across all drives in the array. By having multiple parity drives, parity information can be written to more than one drive simultaneously. This removes the overhead associated with RAID 4's read/modify/write.

Error Recovery

•  Error recovery is  through the use of parity information distributed across multiple drives

•  Done automatically by the disk controller

Characteristics

•  Data is spread across all the drives in blocks

•  Drive spindles are not synchronized

•  Parity is spread  across all drives

•  Independent actuators

Advantages

•  Good performance for all transaction processing systems

•  Multiple actuator seeks improve speed

•  Increased reliability and data availability

•  Transparent to system software

•  Increased reliability with minimal drive cost

Disadvantages

•  Performance degradation during data reconstruction


RAID  LEVEL 6: Mirrored Striped Disks

This technique combines all the benefits of RAID Levels 0 and 1 − providing the speed of RAID Level 0 and the reliability of RAID Level 1. As such, it is today's fastest RAID solution. RAID 6 performance and reliability is achieved by striping data across the drives over a single SCSI channel and then  mirroring the striped array across the second SCSI channel. Striping (RAID 0) provides speed, while mirroring (RAID 1) provides reliability.

Error Recovery

•  Error recovery is  through the use of mirrored drives

Characteristics

•  Data is spread and striped across all the drives in blocks

•  Data is duplicated across two SCSI Buses

•  Drive spindles are not synchronized

•  Number of drives and performance is scalable

Advantages

•  Highest I/O transaction rate of any RAID level

•  Multiple actuator seeks improve speed

•  Maximum data availability

•  Transparent to system software

•  No performance penalty after a drive failure

•  No performance penalty in high write environments

Disadvantages

•  An instant 100% cost overhead

•  2x the space and power requirements


Selecting a RAID Mode

In theory, RAID arrays composed of convential hard drives can function for hundreds or even thousands of years without losing data because of a disk failure.  RAID offers other benefits;  it can improve I/O performance, make servicing simplier and quicker, and allow users to fine tune the drive system to match their specific application needs.  Different levels of RAID will suit different application environments. There are three basic criteria for choosing a RAID implementation:

1.	Cost

2.	Performance

3.	Data Availability

Cost

Today, storage subsystems are often the choke point in overall system performance and reliability.  With increasing use of peer-to-peer networks and client/server solutions, failure of even a single drive can bring down the entire network.  This unwanted action can essiently cripple mission-critcal applications in a split second.  The cost of the resulting service interruptions or more importantly the data loss can be staggering.    Server downtime has a price.  The loss of a critical business networking operation going down will result in a loss of productivity, effiency, and customer perception.  All of these factors have a measurable money value associated with them.  Considering the cost of such disk releated issues, it is failry easy to justify the cost of a RAID solution in Xpress/MX server platform.

However, redundacy also comes at a price.  Fault-toerant storage systems normally go hand-in-hand with other redundant components as well.  These extra meausres of redundacty contributes to the higher overall system cost.  A defective power supply, a non-error correcting memory subsystem, a fan is lost causing the hard drives to overheat, or the inevitable component failure can all interrupt access to the RAID storage system or even cause data loss.  According to leading authorities, when the server is built with enough redundant subsystems and components, it could in theory deliver millions of hours of uninterruptable use.  This now brings up the question every MIS manager must answer;  if the server and the redundant equipment purchased is easily going to be obsolete after 150,000 hours (about 17 years) of use, does it make sense to pay the extra money for this level of system redundancy?  There does become a point where common sense must point out that each additional dollar spent on redundancy delivers a diminishing practical return of the investment.

Performance

Analyzing the performance of RAID designs can become a very complex task.  However, it is usually not too difficult to actually determine the best RAID solution for a specific application.  To select the best level of RAID for your system, it's important to understand how your data is accessed.  The most important variable is the applications' I/O behavior.

RAID Comparison Matrix

	RAID 0	RAID 1	RAID 3	RAID 5	RAID 6
Cost	Excellent	Poor	Good	Good	Poor
Data Availability	Poor	Excellent	Excellent	Excellent	Excellent
Read Bandwidth	Good	Good	Excellent	Good	Good
Write Bandwidth	Good	Good	Excellent	Fair	Good
Read Small Block I/O per second	Excellent	Excellent	Poor	Excellent	Excellent
Write Small Block I/O per second	Excellent	Good	Poor	Fair	Good
Image Processing

This type of computing, like many scientific programs, involves the reading and writing of very large sequential files. RAID Level 3 is best suited to this and other types of applications that require large amounts of data very quickly, because RAID 3 can transfer data simultaneously from all the drives in the array. CAD/CAM and multimedia are examples of image processing applications.  Because the XRAID4 does not support the RAID Level 3 implementation, then RAID Level 5 in most image processing applications would be best suited when using the XRAID4 disk controller.

Transaction Processing

This type of computing typically involves a large number of concurrent requests, such as airline reservation systems, POS terminals and bank tellers. Such systems are usually measured in the number of transactions they can handle per second, rather than the length of a transaction. RAID Level 5 provides excellent performance in such systems because all of the drive actuators operate independently to maximize transaction rates. However, RAID Level 6 gives the best performance for this computing.

Office Applications and Database servers

This  type of environment involves running many small applications. Such applications could well be DOS, OS/2, Novell, Windows NT, or UNIX-based and can vary from engineering applications to word processing.  RAID Level 5 suits such applications well, as it can handle the small block requests extremely well.

	RAID Level 0	RAID Level 1	RAID Level 3	RAID Level 5
CAD / CAM			Best Choice	Best Choice
Database Mngr.			Best Choice	Best Choice
File Server		Best Choice
Image Processing			Best Choice	Best Choice
Multi Tasking	Best Choice			Best Choice
Multi Media		Best Choice
Office Automation	Best Choice			Best Choice
Simulation App.			Best Choice	Best Choice
Transaction Proc.	Best Choice			Best Choice


Getting the Most out of RAID

Once you have chosen a RAID architecture for your application, you'll have to determine how to minimize multiple drive accesses for single operations.

Block size is an important factor in optimizing system performance. In RAID 3, the block size spans all the physical drives in the array. RAID 0, 1 & 5 are based on block striped arrays which divide the data into multiple blocks, which are stored on different drives. The idea is to balance the load across all the drives in the array equally. This is achieved by allowing single drives to independently service requests that are equal to or less than the block size. To take full advantage of a block striped array, the controller must be able to queue commands from the host. Command queuing lets the array controller service multiple I/O requests concurrently. The optimum solution is to keep all the drives busy while the adapter is working through command reordering or data buffering.

 The XRAID4 uses a 16K byte block size, which is large enough to allow the majority of accesses to be within one block. Accesses that are larger than one block will involve accessing two or more drives.

The following two tables show the performance degradation seen on both RAID 1 and RAID 5 systems:

Performance of a RAID 1 system with 8 drives

% of 16K Reads	Block Size	I/O per sec	Degradation
20%	16K	284
20%	8K	243	14%
100%	16K	254
100%	8K	146	43%
Performance of a RAID 5 system with 5 drives

% of 16K Reads	Block Size	I/O per sec	Degradation
20%	16K	178
20%	8K	152	14%
100%	16K	159
100%	8K	91	43%
To see the advantages of RAID 5 in a practical system, due to the importance of high I/O rates in server applications, we can compare a high-performance RAID 5 implementation using five Wren VI drives against the Compaq IDAC RAID 4 implementation with four synchronized Connor drives. The graph below displays random 8 KB-block I/O's performed per second versus the percentage of I/O's which were read operations.

Related Topics:

DATA Availability


DATA Availability

In all RAID levels (but Level 0), the disk subsystem is consumed by redundant data on the hard drives.  The actual overhead of a disk array subsystem is the percentage of total hard drive capacity dedicated to storing the required redundant data.  These overhead requirements for each RAID Level configuration are directly associated with the type of drive configuration and number of hard drives.  The actual hard drive storage capacity is the amount left after subtracting the overhead for the data redundnancy. The table below shows the usable percentage of actual disk drive capacity for the various RAID levels.

	Four Hard Drives	Five Hard Drives	Six Hard Drives	Seven Hard Drives
RAID 0	100%	100%	100%	100%
RAID 1	50%	Can't Do This	50%	Can't Do This
RAID 3	75%	80%	83%	86%
RAID 5	75%	80%	83%	86%
RAID 6	50%	50%	50%	50%
For RAID Level 0, the actual overhead is zero, but the user gets no redundancy for the data on these hard drives.  For Levels 1 and 6, the overhead is 50% since half of the hard drives used store the redundant data.  In the case of RAID Levels 3 and 5, the array of the number of drives is directly perportionable to the overhead (1 divided by the number of hard drives) since the storage requirement for the parity codes is equivalent to one hard drive.


XRAID4 RAID Controller

The Intel XRAID4 EISA SCSI Disk Array Controller is a high performance caching RAID controller giving Xpress systems the ability to operate non-stop with a high degree of fault tolerance. Key components of the XRAID4 are:

1.	EISA bus interface; acts as a bus master

2.	Intel960 RISC Processor

3.	On-board cache memory up to 64 MB

4.	Field programmable BIOS & system firmware in a Intel Flash memory device

5.	Two independent Fast SCSI channels using the NCR53C70 controller

Related Topics:

EISA Bus Interface

INTEL960 RISC Processor/Cache Memory

Field programmable BIOS

SCSI Bus Interface

Software Drivers


EISA Bus Interface

The XRAID4 Controller connects to the host CPU through the Extended Industry Standard Architecture (EISA) bus interface. The EISA bus is a backward compatible 32-bit bus capable of high data transfer rates while providing adequate bandwidth for today's high performance server architectures. The EISA bus allows 32-bit Master mode class C transfers at rates of up to 33 MB per second.


Intel960 RISC Processor/Cache Memory

The XRAID4 is based on the Intel960 32-bit RISC processor. This CPU controls all functions of the controller, including SCSI bus transfers, EISA bus transfers, RAID processing, configuration, error recovery and drive rebuilding. The disk cache memory on the XRAID4 can be configured to be 4, 16 or 64 MB depending on the system performance required.


Field programmable BIOS

The XRAID4 contains controller BIOS which automatically executes after the Xpress Deskside system has completed the Power On Self Test (POST). The controller BIOS intercepts all INT13 system BIOS calls, converts and redirects them to the Intel960 onboard processor. The XRAID4 firmware is based in a Flash memory device. The Flash device allows the firmware to be upgraded from a floppy diskette and also stores the disk controller's current configuration information, drive failure data, and dynamic reconfiguration data. This process allows an EISA-based host system to run DOS without any device drivers. This function also allows the system to load an appropriate driver from the disk to run operating systems like SCO UNIX, Windows NT,  or Novell Netware.


SCSI Bus Interface

The XRAID4 uses the Small Computer Systems Interface (SCSI) bus to connect to the hard drives, tape drives, CD-ROMs, and other SCSI devices. The XRAID4 has two independent SCSI channels, each using an NCR 53C720 SCSI processor. Each channel supports seven hard disk drives and data transfers up to 10 MB per second. The NCR 53C720 processor with Fast SCSI support conforms to  SCSI-2, which is a superset of the older SCSI-1 standard.


Software Drivers

The XRAID4 includes many software support packages. Some of these drivers are embedded into the operating system and are available upon installation. These include:

XRAID4 Utilities for MS-DOS

•	The !XRAID960.CFG file is used by the EISA Configuration Utility to configure the Intel XRAID4 into the Xpress/MX Deskside system.

•	Disk Array Configuration Utility is used to interactively configure the SCSI devices connected to the controller to form a RAID system.

•	XRAID4 DOS Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

Software Drivers for SCO UNIX V.3.2.4, ODT 2.0, ODT 3.0

•	The XRAID4 driver for SCO UNIX is loaded at system power up to access the array.

•	XRAID4 SCO Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

•	Two programs are used for system administration (SYSADM) and monitoring of the card's activities under SCO UNIX.

Software Drivers for Novell Netware 3.1x, 4.01, 4.1

•	The XRAID4 driver for Netware is loaded at system power up to access the array.

•	XRAID4 Netware Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

•	Two Netware loadable modules are used for system administration and monitoring of the card's activities under Novell Netware.

XRAID4 Utilities for IBM OS/2 2.11

•	The !XRAID4.CFG file is used by the EISA Configuration Utility to configure the Intel XRAID4 into the Xpress/MX Deskside system.

•	Disk Array Configuration Utility is used to interactively configure the SCSI devices connected to the controller to form a RAID system.

•	XRAID4 OS/2 Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

Software Drivers for Novell UNIXWare 1.1, 2.0

•	The XRAID4 driver for UNIXWare is loaded at system power up to access the array.

•	XRAID4 UNIXWare Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

•	Two programs are used for system administration and monitoring of the card's activities under UNIXWare.

Software Drivers for Microsoft Windows NT 3.1, 3.5

•	The XRAID4 driver for Windows NT is loaded at system power up to access the array.

•	XRAID4 Windows NT Toolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

•	Two programs are used for system administration and monitoring of the card's activities under Windows NT.

Software Drivers for Banyan Vines 5.54, 5.6

•	The XRAID4 driver for Banyan Vines is loaded at system power up to access the array.

•	XRAID4 BanyanToolkit is used to display and set the status of the XRAID4 and the SCSI devices connected to it.

•	Two programs are used for system administration and monitoring of the card's activities under Banyan Vines.


RAID Installation

The XRAID4 Disk Array Controller is an EISA add-in card designed for use in Xpress Deskside servers. This disk controller has a two channel SCSI-2 adapter that connects directly to the SCSI distribution board in Deskside/MX systems via two single-ended SCSI cables. The board holds four socketed SIMMs for a total memory capacity of 64 MB. The XRAID4 controller board has three headers J1, J2, and J5 (J2 and J5 are for factory testing and should not be used). J1 is a 6-pin header and provides drivers for three status LEDs.

Pin	Description
1-2	SCSI Activity LED
3-4	EISA Activity LED
5-6	Write Pending LED
Notes:

An external series resistor is not required for these LEDs. If power is lost or the Xpress system is reset while the Write Pending LED is on, any data held in the RAID cache will be lost.

•	SCSI Activity LED indicates one or both SCSI channels are sending or receiving data.

•	EISA Activity LED indicates the XRAID4 is sending or receiving data across the EISA Bus.

•	Write Pending LED indicates the XRAID4 cache holds data not yet written to the drives.

XRAID Disk Controller Quick Installation

The instructions can be used as a quick installation reference for installation of the XRAID4 board.  The installation of drivers specific to NetWare, OS/2, SCO UNIX, UnixWare, Windows NT and Banyan are covered later.

1.  Install XRAID4 board into the Xpress/MX server.  Depending on configuration of arrays you may need to refer to the Xpress Deskside manual for detailed information on how to configure SCSI distribution board.

2.  Install hard drives into the server.  Power and SCSI cables will connect to drives from the SCSI distribution board.  Each SCSI channel can support drive IDs ranging from 0-6.

3.  Boot computer with ECU and configure XRAID4 board with desired.  You will need to copy the *.cfg files from the DAC960 Disk Array Configuration & Utilities diskette to your ECU diskette

4.  Reboot computer with DAC960 Disk Array Configuration & Utilities diskette.

5.  Run mouse driver.  Config utility will execute without mouse driver installed, but it is easier with a mouse installed.

6.  Execute DACCF.EXE from Disk Array Configuration & Utilities diskette.

7.  From Main Menu, select New Config.

8.  Select Open Pack Definition button.

9.  Point to, and click on the drives to be assigned to the pack being defined.

10.  Select Close Pack Definition button.

11.  Repeat steps 8 thru 10 for each pack being defined.  Most of the operating systems should have the first partition less than 2048 MB.  Other subsequent partitions or system drives may be more than 2046 MB.  Consult the README.TXT file for specific driver being loaded.

12.  Select the Arrange Packs button.  Then select packs to be arranged in order of preference.

13.  Select the Define System Drive button.

14.  Select the System Drive Definition button.  Enter start MB(first drive will usually start at 0) then hit the Enter key.  Enter size of drive in MBs then hit the Enter key.  Select the type of RAID for this array then hit Enter.  Enter start MB for next drive if using more than one array.  This will usually be the number stated above as start MB.  Enter size of array in MBs and select type of RAID to be used for this array.

15.  Select the Exit button.  Click on Save.  This will bring you out to the Main Menu.

16.  From the Main Menu, select the Initialize System Drive buttton.  Click on the status bar of each drive that is displayed to begin initialization of the drives.  Initialization can take approximately 20 minutes on a 2GB RAID 5 array.

17.  Click on Exit when the initialization is completed.

18.  Select Exit from the Main Menu and then perform a COLD BOOT to initialize the system.

19.  Run FDISK to create a DOS partition on the arrays and format the drives if desired.

Related Topics:

Xpress/MX Deskside


Xpress/MX Deskside

The Xpress/MX Deskside Premium Server is designed with the needs of high-end servers in mind. As a result, early in the design of the chassis Intel Engineering concentrated on the use of  SCSI peripherals. The market had dictated ESDI and IDE peripherals, but these devices did not have the benefits of SCSI. ESDI peripherals suffer because the disk controllers cannot use zone recording techniques to increase hard drive capacity. IDE peripherals suffer because the data route to the disk is a single threaded path through a set of register files defined in the original WD1003 disk controller.

SCSI controllers and peripherals can use zone recording and allow for multiple reads/writes to be carried out on the same SCSI bus. The multiple executions of reads and writes is particularly useful in server environments, where the feature is used by operating systems like UNIX, Novell, and OS/2.  Furthermore, SCSI is not limited by the number or types of peripherals on the bus and can use up to seven varying peripherals on each controller. Peripherals ranging from tape drives to optical disks, CD-ROMs, scanners and printers can be attached to the same SCSI controller with using the appropriate driver.

Intel Engineering made a decision with the Xpress/MX Deskside Server chassis to offer eight half-height 3½" bays for hard disk storage and three 5¼" half-height bays for removable media (i.e.; floppy drives, WORM/CD-ROMs and tape/DAT backup devices).

Related Topics:

INSTALLING THE XRAID4

SCSI DISTRIBUTION BOARD

HARDWARE CONFIGURATION

Installing A RAID System

questions


INSTALLING THE XRAID4

The first step when installing the XRAID4 disk controller card in the Deskside/MX Premium Server is to decide whether the SCSI Distribution Board will be configured for one or two buses. Since the XRAID4 has two channels, users normally will configure the SCSI Distribution board for two SCSI buses. This is done by terminating the first bus at J13. Once this has been completed, the XRAID4 disk controller is installed in either EISA bus master slots 7 or 8 on the system baseboard. Once the XRAID4 has been configured and the hard disks installed in the system, the disk array must be software configured.


SCSI DISTRIBUTION BOARD

Intel Engineering opted to eliminate cabling problems by designing a SCSI Distribution Board to provide power cables and termination for up to two SCSI buses. The board also takes care of the issue of terminating the bus on the last peripherals (per the SCSI specification) by terminating on the Xpress server front panel board or the SCSI distribution system. When installing SCSI devices in the Deskside/MX Premium Server, all SCSI devices should have their terminators removed.

The top three peripherals are powered by three separate standard power connectors and can connect to the SCSI bus through the SCSI cable that goes to the front panel for termination. The other hard drives are powered from the SCSI distribution board as shown on the left.

SCSI Distribution Board Jumper Pin Detail


HARDWARE CONFIGURATION

Simple Case

This is how the board is shipped. The SCSI 1 cable is connected to the disk controller and any of the SCSI connectors (D1 to D11) can be used to connect a SCSI peripheral. In this mode, there is a limit of seven SCSI devices.

SCSI Distribution Board in Pass-Through Mode

Advanced Case

In the more advanced case, two jumper blocks on the back of the SCSI Distribution board must be moved to the closed position. By closing the SCSI bus at the TSJ connector, the SCSI distribution board is terminating the SCSI bus and linking it to the peripherals D1-D4. This allows the SCSI distribution board to make a further connection at the SCSI bus from a second SCSI Controller which will drive peripherals D5-D8 and D9-D11.

SCSI Distribution Board in Terminate  Mode

Whether an OEM decides to go with the first or the second implementation will be based on their application and their customers' needs.

Xpress/LX Deskside

The Xpress/LX Deskside Mainstream server is designed as a medium-sized server, as compared to the Deskside/MX Premium chassis. The Mainstream server allows for a smaller number of 3½" disk drives while still maintaining the capability to utilize up to 384 MB of system memory and a Pentium processor module. The chassis allows two IDE hard disks and up to seven SCSI peripherals. Intel Engineering goals in designing this chassis were very similar to those used in designing the Xpress Premium Deskside/MX server chassis.

The Mainstream server chassis allows four internal 3½" SCSI hard disks which can be snapped into place for easy access, while providing three half-height 5¼" accessible peripheral bays for back up and other devices (e.g.; CD ROM, DAT drives, tape drives, floppy drives).

The SCSI cable on the Deskside/LX is routed from the disk controller, past the disk drives, and ending at the accessible devices. Power to the peripherals is provided by two power cables which are routed close to the drives for easy access.

Xpress/LX Deskside Drive Power Cabling


Installing A RAID System

The Xpress/LX Deskside server is well suited for software and hardware implementations of RAID.  There are many software solutions on the market based on standard hard disk controllers such as the Adaptec 1740 or the DPT 2012B. These high performance EISA controllers provide reasonable performance which can be used with many vendors' software to achieve disk drive redundancy. Appendix A includes a list of software vendors.

Higher performance is available through the Intel XRAID4 disk controller, which can be used with only one of its two SCSI channels active. Like the Xpress/MX Deskside Premium Server, EISA bus master disk controllers normally are installed in either slot 7 or 8 to make cable routing easier and to be recognized as logical bus masters 1 or 2.


questions

Why allow for up to 11 SCSI peripherals in the Xpress/MX Deskside Server when the SCSI bus can only support seven peripherals on a single controller?

The Xpress/MX Deskside chassis is designed to allow for over 12 GB of easily removable and installable hard drive storage plus backup peripheral devices. This requires more than seven SCSI devices. An analysis of the SCSI bus reveals the bus will be saturated if four or five high-speed SCSI devices are driven at full speed by the host controller and the Intel Xpress CPU module. This would create an unacceptable bottleneck in a high-end server. Intel Engineering designed the SCSI distribution board hardware to allow for two high performance controllers (or one with two channels) and allow for a maximum of 14 SCSI peripherals (11 internal devices and three external devices).

Why did we not allow for 5¼" full-height hard drive storage?

The cost of 3½" drives have dropped below the cost of 5¼" drives in capacities up to (and soon including) 1 GB. It is true, for at least this year, that if you require a single expensive, very high capacity (1.6 GB to 3.0 GB) disk drive, 5¼" normally is the main solution. However, such a solution is extremely inefficient and risky. It's inefficient because  the disk controller can only transfer data in and out of the drive through a single interface. The risk is that no matter how reliable disk drives become, as capacities increase, so does the risk of losing some data.


XRAID4 Configuration

BIOS

EISA Configuration

Disk Array Configuration Utility


BIOS

The BIOS on the XRAID4 provides access to the drives in the array by intercepting INT13 and includes a single threaded interface for access to the first two drives. This allows other operating systems (i.e.; UNIX or Novell) to load the appropriate device drivers from the hard disks in the array. The XRAID4 BIOS presents a system drive to the host as a large disk with 32 sectors per track and 128 heads per cylinder. A maximum DOS limit of 2 GBs is supported without the use of any device drivers. Any disk access beyond the first 2 GB of each drive requires loading the appropriate driver. The BIOS can (and is recommended to) be shadowed for operation under MS-DOS. Shadowing improves disk I/O speed under DOS, but is not relevant under UNIX or Novell, since these operating systems use their own 32-bit, protected mode drivers to achieve optimum multi-threaded performance. The BIOS is shadowed by the EISA Configuration Utility. However, shadowing should be disabled if upgrading the XRAID4 Flash BIOS. It is important to realize that the BIOS operates in real mode. Protected/Virtual mode environments (such as MS-Windows) are not supported without the appropriate device driver.

Related Topics:

XRAID4 BIOS Startup Sequence


XRAID4 BIOS Startup Sequence

The XRAID4 BIOS is executed after the Xpress Deskside system has finished its POST and has scanned the EISA Bus for other add-in card BIOS code. The Xpress baseboard passes control to the XRAID4 BIOS which will execute its own POST before passing control back to the baseboard. The BIOS checks to see if any devices are connected through the SCSI Bus. Failure of any already configured SCSI device to report will cause the XRAID4 to display a failure message on the screen.


EISA Configuration

The XRAID4 is configured into the Xpress Deskside system through the EISA Configuration Utility (ECU). This program configures the disk controller and checks for I/O and addressing conflicts. To execute the ECU, you must first copy the XRAID4 configuration file (!XRAID960.CFG) from the utilities diskette to your system ECU diskette. The ECU will automatically detect the XRAID4 disk controller in the Xpress server. Selecting the XRAID4 configuration will display the following screen of options.

You can now select each of the options and modify the appropriate settings:


Disk Array Configuration Utility

The Intel XRAID4 disk controller can have many SCSI hard disks attached to it at any one time. These devices can be arranged in an unlimited number of logical configurations. A DOS-based program (DAC960CF.EXE) is used to configure the array for use by MS-DOS, Novell or the SCO UNIX operating systems. The DAC960CF.EXE program must be executed to:

•	Format the drives in the array

•	Configure one or more physical packs

•	Configure one or more system drives, their corresponding RAID level and cache policies

•	Initialize system drives

Once these procedures are completed, the disk array is ready for use by the operating system. This program, like the ECU, is executed from DOS and stores the final disk array configuration in the XRAID4's Flash memory device.

The XRAID4 program can be used with a mouse. The first step in setting up the disk array is to choose the option FRESH CONFIGURATION. The next screen will allow you to define an array using up to seven drives per SCSI channel. The screen will automatically highlight the active drives. The RAID Level, cache policy (write back or write through) and the size of the system drive should be selected. The DAC960CF program has the following options on startup:

Menu Option	Action
Automatic Configuration	Create RAID 5 Configuration quickly
New Configuration	Create New Configurations
View/Update Configuration	View/Add Installed Configurations
Initialize System Drive	Perform RAID Formatting on drives
System Drive Consistency	Check redundant info. for correctness
Rebuild Device	Re-create Redundant RAID Information
Exit	Terminate Program
Once the disk array configuration has been saved, the system drive must be initialized. The initialization takes the form of writing the ECC data on all drives in the pack. The main menu also provides the ability to view and update the configuration after the array has been in use. Once this operation has been completed, the disk array is ready for use. The last option allows the reconstruction of a failed drive by recreating redundant data on the replaced unit. This option can also be used to check for any inconsistencies in data held on the drives in the disk array. However, detection of an inconsistency is usually fatal and means the loss of data. The most common failure type would be errors in the operating system or the loss of power to the Xpress Deskside system during a write update.

Related Topics:

Detailed XRAID Configuration for Installation in a Novell Server

Detailed XRAID Configuration Guidelines for Installation in an OS/2 (2.1) Lotus Notes or OS/2 Application Server

Detailed XRAID Configuration Guidelines for Installation in a OS/2 (2.0) DEC PATHWORKS  cc:Mail Server

Detailed XRAID Configuration Guidelines for Installation in a SCO UNIX Server

Detailed XRAID Configuration Guidelines for Installation in a Banyan Server

Detailed XRAID Configuration for Installation in a UnixWare Server

Detailed XRAID Configuration Guidelines for Installation in a Microsoft Windows NT Server


Detailed XRAID Configuration for Installation in a Novell Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0CC000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.

NetWare Driver Installation

These are the minimum steps are to be performed:

1.  Copy the contents of the DAC960 Disk Array NetWare 3.x and 4.x Drivers diskette to the directory on the C: drive where the NetWare operating systems files reside.

2.  Load SERVER.EXE.

3.  Load DAC960.DSK from the appropriate directory on the C: drive.  (Example - LOAD C:\NETWARE\DAC960.DSK)

4.  It is recommended not to define a Netware boot partition greater then 2048MB.

These steps will enable NetWare to use the XRAID4 board.  There are other NetWare utilities available on the DAC960 Disk Array NetWare 3.x and 4.x Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.


Detailed XRAID Configuration Guidelines for Installation in an OS/2 (2.1) Lotus Notes or OS/2 Application Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0C8000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.

The cache setting should be set to Write-Back for better performance. This is done using the XRAID utility.

OS/2 Driver Installation

1.  Copy contents of DAC960 Disk Array IBM OS/2 2.x Drivers diskette to thje OS2 subdirectory where the operating system files reside.

2.  Change the BASEDEV line in the CONFIG.SYS file.

3.  It is recommended not to define an OS/2 boot partition greater then 2046MB.

These steps will enable IBM OS/2 2.1 or 2.11 to use the XRAID4 board.  There are other OS/2 utilities available on the DAC960 Disk Array OS/2 Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.


Detailed XRAID Configuration Guidelines for Installation in a OS/2 (2.0) DEC PATHWORKS  cc:Mail Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0C8000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.

We recommended configuration for arrays is to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using four physical drives.  The arrays should ideally be configured with drives that are all the same size (e.g., 540MB drives or 1.2GB).  It is also highly recommended to install an additional drive to be used as a hot spare.  This drive must be the same size as a single drive in the array.  The cache setting should be set to Write-Back for better performance, but only when a UPS is supplying a battery reserve.

OS/2 Driver Installation

1.  Copy contents of DAC960 Disk Array IBM OS/2 2.x Drivers diskette to thje OS2 subdirectory where the operating system files reside.

2.  Change the BASEDEV line in the CONFIG.SYS file.

3.  It is recommended not to define an OS/2 boot partition greater then 2046MB.

These steps will enable IBM OS/2 2.0 to use the XRAID4 board.  There are other OS/2 utilities available on the DAC960 Disk Array OS/2 Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.


Detailed XRAID Configuration Guidelines for Installation in a SCO UNIX Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0CC000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.  The CD-ROM is recommended to be on the same SCSI channel as the bootable system drives.  Normally the LUN is ID#5.  If a tape drive is required this must be located as ID#2.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.  The cache setting should be set to Write-Back for better performance. This is done using the XRAID utility.

SCO Unix Driver Installation

1.  At "Boot:  " prompt, type "link" to install the XRAID driver package.  The package name to be added is dac960.

2.  Insert the SCO UNIX Driver diskette for the XRAID card when prompted.  You will likely be asked to insert the N1 and N2 SCO diskettes.

3.  The SCO UNIX system will extract and link the dac960/XRAID driver onto the system hard drives.

4.  It is recommended not to define a SCO UNIX boot partition greater then 2048MB.

These steps will enable SCO UNIX V.4.3, V.4.3MPX, ODT 2.0, or ODT 3.0 to use the XRAID4 board.  There are other SCO UNIX utilities available on the DAC960 Disk Array SCO UNIX Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.


Detailed XRAID Configuration Guidelines for Installation in a Banyan Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0CC000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.  The cache setting should be set to Write-Back for better performance. This is done using the XRAID utility.

Banyan Driver Installation

Banyan drivers are not shipped with the XRAID4 board... they are found in Banyan 5.53 (and higher version.  They are fully documented in the Banyan reference material.


Detailed XRAID Configuration for Installation in a UnixWare Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0CC000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 15 (Edge)

Hardware Configuration Information

The recommended slot is 7, but the interrupt must be IRQ15.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.

Novell UnixWare Driver Installation

1.  At "Boot:  " prompt, type "link" to install the XRAID driver package.  The package name to be added is dac960.

2.  Insert the UnixWare Driver diskette for the XRAID card when prompted.  You will likely be asked to insert the N1 and N2 UnixWare diskettes.

3.  The UnixWare system will extract and link the dac960/XRAID driver onto the system hard drives.

4.  It is recommended not to define a UnixWare boot partition greater then 2048MB.

These steps will enable UnixWare 1.0 and 1.1 to use the XRAID4 board.  There are other UnixWare utilities available on the DAC960 Disk Array UnixWare Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.


Detailed XRAID Configuration Guidelines for Installation in a Microsoft Windows NT Server

ECU Configuration Information

Slot 7 DAC960 RAID Controller Card

BIOS (16k) Base Address	0CC000H - Default

DAC960 disk spin-up options	2 disks started every 6 seconds

DAC960 SCSI Channel 0 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 0 tag-queuing	Enable tag-queuing - Default

DAC960 SCSI Channel 1 transfer-rate	Synchronous, 10 mega-transfer per sec.(Fast) - Default

DAC960 SCSI Channel 1 tag-queuing	Enable tag-queuing - Default

DAC960 Interrupt	Interrupt 11 (Edge) - Default

Hardware Configuration Information

The recommended slot is 7.  The recommended interrupt is 11.  We recommend using both channels on the XRAID board and the Xpress SCSI distribution board.  This requires setting the terminators on the SCSI distribution board for pass through.  Drives should be configured for staggered spin-up.  This is done usually by setting a jumper on the drive or in the ECU as noted above.  This will ensure that the drives do not over-tax the power supply during the power-up cycle.  The CD-ROM is recommended to be on the same SCSI channel as the bootable system drives.  Normally the LUN is ID#5.  If a tape drive is required this must be located as ID#2.

We recommend configuration for arrays to use a RAID 1 SYS volume using two physical drives, and a RAID 5 DATA using five physical drives.  The arrays should ideally be configured with drives that are all the same size for example all 540MB drives or 1.2GB drives.  It is also recommended to install an additional drive to be used as a hot spare.  This drive is required to be the same size as a single drive in the array.  The cache setting should be set to Write-Back for better performance. This is done using the XRAID utility.

Windows NT 3.1 Installation

1.  When installing NT for the first time, select "Custom Setup" and choose "S" for configuring other channels.  Otherwise, go into "Windows NT Setup" icon and add the XRAID driver.

2.  Choose "other" and install the XRAID driver diskette for Windows NT.

3.  It is recommended not to define a Windows NT 3.1 boot partition greater then 2048MB.

These steps will enable Microsoft Windows NT 3.1 to use the XRAID4 board.  There are other Windows NT 3.1 utilities available on the DAC960 Disk Array Netware/OS2/NT Drivers diskette are described in the XRAID4 manual.  Please refer to the manual for more details.  To install Windows NT 3.5 with a XRAID4 in the Xpress/MX system, use the driver on the Microsoft Windows NT 3.5 CD-ROM.


Glossary of Terms

Actuator

Array

Asynchronous Event Notification

Availability

Auto Detection

Auto Reconstruction

Auto Recovery

Bad Block Table

Bandwidth

Cache Flush

Channel

Consistency Check:

Command Queuing:

Concurrent Reconstruction:

Data Availability:

Data Reliability:

Disconnect:

ECC:

Enhanced Error Recovery:

Error Logging:

Fault Resistant:

High I/O Rate:

Hot Spare:

JBOD:

LUN:

Mirroring:

MTBDL:

MTBF:

MTDA:

MTTDL:

MTTF:

Multiple Rank:

Overlapped Seeks:

Parity:

Partial Drive Failure:

Partial Rank Support:

RAID:

RAID 0:

RAID 1:

RAID 2:

RAID 3:

RAID 4:

RAID 5:

RAID 6:

Rank:

Rebuild:

Recovery:

SCSI Drive:

SLED:

Spindle Synchronization:

Striping:


Actuator

The mechanism that moves the read/write head in a disk drive.


Array

Any group of disk drives in a system.


Asynchronous Event Notification

This allows the disk controller and the host to communicate without having to wait for each other to finish the previous task.


Availability

The ability to access data even after a disk drive failure without disrupting any applications.


Auto Detection

The ability to automatically detect a replaced failed disk drive and reconstruct its data.


Auto Reconstruction

The ability to reconstruct the data automatically after the drive's replacement.


Auto Recovery

Reconstructing data without user intervention, once a failure has been detected.


Bad Block Table

An area of disk reserved for keeping information on failed sectors on disk.


Bandwidth

The amount of data transferred during a set period of time.


Cache Flush

The act of writing all the data in the cache to the disk.


Channel

A direct path to a set of disk drives.


Consistency Check:

Checking drives with a shared parity drive to see if their XOR-ed data matches.


Command Queuing:

Issuing multiple commands and letting the controller execute them out of sequence.


Concurrent Reconstruction:

Reconstructing data of a failed drive while running an application.


Data Availability:

The ability to access data when needed.


Data Reliability:

The ability of a computer to operate and deliver data without failure over a period of time.


Disconnect:

Freeing the SCSI bus while a drive is seeking and reconnecting when the drive is ready to transfer data.


ECC:

Error Correction Code.


Enhanced Error Recovery:

The ability to keep track of partial failures during the lifetime of a unit and analyze it to find early failures.


Error Logging:

The ability to store errors between service periods.


Fault Resistant:

The ability to keep functioning after a single failure.


High I/O Rate:

High I/O rate applications request small lengths of data frequently every second.


Hot Spare:

A spare disk drive that is kept operational in the system, in case a unit fails. After the failure, the spare unit replaces the failed unit.


JBOD:

Just a Bunch Of Drives, a combination of drives on a controller.


LUN:

Logical Unit Number.


Mirroring:

A technique where the data on each drive is duplicated on a mirrored drive.


MTBDL:

Mean Time Between Data Loss


MTBF:

Mean Time Between Failure.


MTDA:

Mean Time of Data Availability.


MTTDL:

Mean Time To Data Loss.


MTTF:

Mean Time To Failure.


Multiple Rank:

The ability to support multiple groups/ranks of drives.


Overlapped Seeks:

Issuing multiple actuator movement requests before any single one has finished.


Parity:

The data that is used to detect/correct single bit failures.


Partial Drive Failure:

Failure of a single sector on a drive.


Partial Rank Support:

The ability to support certain RAID modes.


RAID:

Redundant Arrays of Inexpensive Disks.


RAID 0:

Data Striping without Parity.


RAID 1:

Disk Mirroring.


RAID 2:

Parallel Array with Hamming code.


RAID 3:

Parallel Disk Array.


RAID 4:

Data striping with a dedicated parity disk.


RAID 5:

Data striping with a parity distributed across all the disks of the array.


RAID 6:

Mirrored striped disks.  A combination of RAID-1 and RAID-5.


Rank:

A group of disk drives viewed as one drive.


Rebuild:

To reconstruct the data in a replaced disk.


Recovery:

Reconstructing the user's data from the remaining drives in an array after a drive failure.


SCSI Drive:

A disk drive conforming to the Small Computer System Interface.


SLED:

Single Large Expensive Disk.


Spindle Synchronization:

The ability to synchronize the disk drive's rotation, so that all drives respond to a data request simultaneously.


Striping:

The ability to use multiple drives simultaneously and use them all as one logical unit.