Channels
   The Cheetah has two channels. Each channel is controlled by an NCR53C720. The header J1 is Channel 1. It usually is attached to an internal array, but with the addition of a side card, it can controll an external array. The second channel uses J2 OR the external port, J9. This is still one channel, so one can use either the internal port, OR the external port. Do NOT try to use both J2 and J9 at once. 

Notes:
NVSRAM is a Benchmarq 28 pin 8Kx8  bq4010YMA-200, Spec sheet
  Another equivalent is a Dallas DS1225Y-200, spec sheet

NVSRAM Functions
  Each NV SRAM has a self–contained lithium energy source and control circuitry which constantly monitors VCC for an out–of–tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent data corruption. 

Cable Parts
   The mini C68 for the Channel edgecard connectors is the Molex 71660i, part# 15-92-3068, called a half pitch Centronics, or a VESA Media Connector. Suprise! AMP makes a similar part (mini-C68) AMP Part 1-557089-2 Any cable with a .025 pitch, 28 to 30 AWG will work with either connector. 

A Better Cable Hack?
Allen Brandt wrote: 
> A small, shotty attempt to get something uploaded concerning the PS/2. HERE

My Take on it:
   I am starting to have neurons fire. Actually, Allen provided the push. Al went and slit the conductors for better flexibility (in pairs). 
   Could you slit the flat cable up towards the controller and get the very flexible cable bundle of the IBM original? The black sheathing is available from Jameco for about $1 a foot. Well worth it, IMHO. (Start the slit with an X-Acto and use the reverse of the blade to finish parting the conductors???) 
   The sheathing is Techflex Cable Sleave, looks to be the 3/8" size. Sold in a 25' spool. Part #162157, Product # CCPT2X per spool $14.95  Techflex is HERE
What kind of signal degredation might occur? Each signal pair hopefully cancels it's noise out. 
   If the Brandt manuever can be done from the top drive connector to the adapter, it might be a close match to the real thing 

LED For Cheetah
   BUT if you take an LED off of J6, pin 1 and 2, it will light when the drives are accessed. Just run a lead up to between the LED blocks in the display panel. Watch the polarity. If the LED doesn't light, switch the header around. You do not need a resistor for this. 
   I tried this, but the LED didn't have enough umph. Pretty dim through the LED Panel. Maybe some sort of a drive circuit? 
  Just had a thought- twist the existing HD LED out of the Op Panel and put the LED that is connected to J6 in there.... 

Possible Cyrix-Cheetah Incompatibility?
Tim Clarke
Hi gang, 
      just thought that I'd better warn you. After checking out the Cyrix 5x86 at 4x clocking (in Type-1 non-SOD w/cache) my PassPlay RAID adapter seems to have been "duffed up". I only get a part of the BIOS v1.05 initialisation/installation message and the machine hangs (with *any* CPU) at CP:96. Looks as though the Flash ROM has been partially overwritten (just a guess). 

Configuration Utility version 2.31 consists out of two disks: 
FWSR Option Disk, #1 ver. 2.31
FWSR Option Disk, #2 ver. 2.31
Readme for FWSR Option Disks

Not sure if this fits- 
RAID Supplemental Diskette Version 2.0    And the Readme.txt RAIDSEND is a utility that provides an OS/2 ONLY command-line interface for performing various tasks on a IBM F/W Streaming RAID Adapter/A, the IBM SCSI-2 F/W PCI-Bus RAID Adapter, and the Mylex PL adapter for the IBM PC Server 704. 

CAUTION!!!
   The Passplay and the Cheetah differ in the microcode, which *may not* be interchanged. The Passplay (FWR) adapter uses a microcode-level 1.6x through 1.99, the Cheetah (FWSR) uses 2.xx levels. If you flash the one adapter with the code from the other you end up in non-functional adapters. 

FWSR Flash BIOS 2.21   For RAID controller WITH external port! 
FWSR Flash BIOS Readme

Cheetah in a Server 500

Setting the CD Rom ID in a Server 500
  I think I saw a patch somewhere to "fix" a CD on the FWSR under NT.

From Rich Nagle
  Following repeated failures of NT 4 Server setup to recognize the CD Rom connected to the passthrough connector on the top backplane, I noticed that the CD Rom was showing up as one SCSI ID# higher than it was when I checked it under the RAID Utility View Configuration.
  After checking the SCSI ID jumper on the backplane (set to LO for IDs 0 thru 5 on the backplane), a sudden flash of inspiration occured- I set the CD Rom to ID 5, went back under the RAID Utilities, and the CD Rom was now ID6. I then deleted, then recreated the array. Now when I ran NT Setup the CD Rom was recognized automatically. 

Linux on FWSR
From Peter
>> Is anyone running linux on one of these machines?

Not on machines with the IBM Raid controller with the old 2.43 firmware. No Linux driver available

The IBM Fast/Wide Streaming Raid Adapter PCI as used in the Server 320/520 MCA-PCI versions is derived from the Mylex DAC960PL - it only has 128K Flash ROM (one 28F010 chip) but a second open socket. Firmware 3.x requires 256K Flash. I'd tried to plug in a second 28F010 ... but I think the old software contained in that chip confused the adapter a bit ... it behaved a little "strange" (long boot time etc.)

What I do not have is an Eprommer that is capable to write the Flash-ROMs of the 28Fxxxx series or I could a) write a spare 2.4x Flash (to keep for the "worst case") and b) clear the 28F010 ROMs I pulled from some old boards. Else I would stuff in a blank ROM in the second socket, have the old 2.xx in the first and run a firmware update 3.x from the DAC960PL on that adapter.

The machines with the older RAID-adapters ("Passplay" and "Cheetah") based on MCA technology are out of the discussion anyway. They are based on the DAC960M technology basically but an older draft of that concept. They use some of the chips of the -M and early -Px adapters (PL / PD) and they are developed by Mylex - but the firmware 3.x is PCI-specific, not MCA. So you can practically forget about using them under Linux since the driver is *particularly* written for the 3.x firmware level.

LVD on Cheetah
>What kind of drives does the RAID take? Is F/W DIFFERENTIAL SCSI the right kind? Or are LVD (low voltage differential) different and it needs them instead? I've never dealt with RAID before.

 From Peter
 Remember the  "Cheetah"-Adapter's "Real Trade Name" ?  IBM Fast/Wide Streaming Raid Adapter /A.
   It it an ordinary F/W indended for single-ended SCSI devices. It does however take U/W LVD drives, because these are downward-compatible to single-ended, which the old "high-voltage differential" are *not*. 
      If you get - for example - a set of U/W "Low Voltage Differential" (LVD) IBM DDRS 4.5 or 9.1GB drives then they will nicely run with the Cheetah. I have some of them in "Starship" - my Server 520 attached to the Fast/Wide RAID Adapter PCI. No problem. You can even mix them
 with "ordinary" F/W or U/W drives. Same for the Cheetah and even the older Passplay.

Interrupt Level
   Set the interrupt level for the adapter.
    <"Level E">, A, B

BIOS Base Address
   BIOS base address. Each adapter must have a unique address range. 
    <"C0000-0C1FFF">, C2000-0C3FFF, C4000-0C5FFF, C6000-0C7FFF, C8000-0C9FFF, CA000-0CBFFF, CC000-0CDFFF, CE000-0CFFFF, D0000-0D1FFF, D2000-0D3FFF, D4000-0D5FFF, D6000-0D7FFF, D8000-0D9FFF, DA000-0DBFFF, DC000-0DDFFF, DE000-0DFFFF

I/O Address
   I/O address. Each adapter must have a unique address range.
    <"1C00-1C1F">, 3C00-3C1F, 5C00-5C1F, 7C00-7C1F, 9C00-9C1F, BC00-BC1F, DC00-DC1F, FC00-FC1F

DMA Arbitration Level
   DMA channel the adapter will use to transfer data.
   <"Level 8">, 9, A, B, C, D, E, 1, 3, 5, 6, 7

Tower Configuration
   How many towers of seven drives will be presented to the user. Any messages regarding drive status are always presented in terms of bays in the tower. When each channel of the Streaming-RAID Adapter/A is connected to a different tower select the '2 Towers' Configuration and when both channels are connected to one single tower select the '1 Tower'
Configuration.
   <"2 Towers">, 1 Tower

Data Parity Exception Handling Support
   Enable or disable the Micro Channel data parity generation
NOTE: System must support this option.
   < "Enabled ">, Disabled

Micro Channel Streaming
   Eenable or disable the Microchannel streaming. NOTE: If the system does not support this then this option will NOT be available.
   <"Enabled ">, Disabled
 
INT 13 Support
   This provides limited support for BIOS INT 13 function calls and is required if boot devices are connected to Streaming-RAID Adapter/A.
NOTE: If the system does not support this (eg. not a T1 upgrade-66 or any T4 complex) then this option will NOT be available.
   < "Disabled">, Enabled