Stuff that is relevant, but chaotic... (fits, doesn't it?)
Create and Maintain your Array
Array technology, features, classifications(FWSR)
RAID Message Table
Hotswap bays for 95A
   Removing side panel from 3 bay cage
   Closeups of microswitches

There is NO external port on the Passplay!

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

NVSRAM Function
  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.
  Don't ask if you can get this cable for $9.99! I have priced out the black sheathing, twist 'n loose 68 wire cable, and the molex connectors. If you bought the cable by the 100' reel (if you can get it shorter, tell me) and the sheathing the same way, the parts alone cost upwards of $50 for a replica of the original FW RAID cable. Can't run with the big dogs if you are whining with the pups.
   No, I do NOT have a pile of them in my closet! No, I do NOT know where to get them at $5 each. No, I do NOT know how to make a replica for $10. It's your data. If you want to cobble a cheap cable up, I suggest buying SCSI-III flat cable from Dalco and crimping on the needed Molex/AMP connectors. But don't blame me if you loose something.

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 theadapter, it might be a close match to the real thing

IML/Boot Limits of Passplays
   The Passplay was introduced for use with non-Flash systems. However, the Passplay does NOT support Int13 or IML. You either have to boot from a floppy or from an IBM IML capable SCSI adapter. A telling sign is the Type 5 form factor card cutouts in the case are on Slots 2-4. A Type 3 form factor SCSI Adapter has to be installed in Slot 1 to support Type 1 and Type 2 complexes that do NOT have the enhanced BIOS.

HD LED Doesn't Work
>Is i a fact that the HD LED does not work on a 9595A with a PassPlay RaidAdp.?
   The fixed disk light is non-functional with both the Server 95 A "Passplay" and Streaming-RAID "Cheetah" MCA RAID adapter.  I suspect this is also the case with other OEM'ed Mylex RAID adapters.

Cyrix/Non-SOD 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).

From Peter
   Having a large cache is only half the truth. Bigger cache means more damage if the controller chokes and cannot write data back to the drives. Large caches on Raid controllers make sense only if they are battery-backed  (Ed. I have seen battery-backed 72 pin SIMMs) and if there is a mechanism that allowes to remove the cache (with the data), replace the adapter, plug back the cache and restart the system to that point where the operation was stopped and write the cache data down to the drives and maintain the integrity of the data / array. 
   The older Raid-controllers (Server-95 Raid "Passplay", Fast/Wide Streaming Raid /A "Cheetah" and Fast/Wide Raid PCI "DAC960") don't have battery backed cache. Even 4MB of cache memory contains a large number of "data-stripes" (usually 8K blocks).
   These data-stripes will be lost if the machine powers down for any reason, or the controller fails, or the operating system hangs. Recalculate how many sectors fit in 4MB - and the higher the number of missing sectors the lower the chance that the Raid-Utility will be able to restore the missing data.

Cache Size Depends On
a) Overall drive data-throughput (buffering x accesses while drives are in *mechanically* causes delay / dead zone / recalibration)
b) Data-stripe size (8K normally - 64K under WinNT might give better results)
c) Operating system (WinNT and OS/2 are very "swap active")
d) Structure of the RAID itself (Raid-5 uses the cache much more than Raid-1 ... because the mirroring is imminently fast with buffering the data).
e) Nature of the data blocks. Consequently high internal redundancy of the data will cause higher "hit rates" within the cache than permanent data-streaming with new data, which void the cached data and only "pass through".

   Like on all caches there is a limit where enlarging the cache any further makes no sense. And I think this limit is at around 4MB on a 5 drives Raid-5 system running under OS/2 or WinNT. The content-redundancy of the data is mostly not given - so the cache is mostly used to buffer the Raid data-overhead between the drives (during reading / writing / synchronizing the Raid structure) - on the transfer between drive-subsystem and processor the cache does not play a major role.
   A larger cache here costs only money and bears the above mentioned risks to render the entire array useless if something crashes. 

Cache Size and Diminishing Returns
From "Mark"
   Generally speaking, increasing the amount of cache will always improve performance. The performance gain will be more for sequential access type applications than for random access type applications. Typically increasing the cache from 2 to 4MB will see a bigger % gain than 4 to 16 MB and that will see a bigger % gain than 16 to 32 MB and so on.

IBM or Generic SIMMs?
   They are 30-pin standard industrial ("generic") SIMMs. Since the original concept allowed 4x1MB, 4x4MB and even 4 x 16MB cache Simms they *must* be generic, because IBM only coded the 256K, 512K and 1MB modules. The 4MB and 16MB are not on IBM's list.

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.

NOTE:All systems, except the 95-466, 95-560, 95 A-466, 95 A-560 and 9585-0Kx, require that the standard SCSI adapter or system board resident SCSI controller remain connected to the IML and/or boot hard file.

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. (See the README coming with the 1.99-level microcode update for the Server 95 RAID adapter)

SR Flash BIOS ver. 1.61 Only for RAID controller WITHOUT an external port on it!
SR Flash BIOS ver. 1.62  Only for RAID controller WITHOUT an external port on it!
SR Flash BIOS ver. 1.63  Only for RAID controller WITHOUT an external port on it!
SR Flash BIOS ver. 1.99  Only for RAID controller WITHOUT an external port on it!
Readme for raid199a.exe (Server 95A RAID Flash disk version 1.99)
Server 95 Array RAID API Module (Non-ASPI)

Passplay Code Releases
From Hakan Gadler
   By the way, why did they jump from version >1.6 something to 1.99? 

From Peter
   IBM "unified" the version numbers for the BIOS and the microcode a bit. Or - to be precise - the return codes. The later Passplay codes ran along with the same RAIDADM software that was used by the "Cheetah" and contained some better infos and other tweaks for performance / safety reasons.

1.60
   The initial code worked only with the early Passplay board releases.

1.61
   Official shipping code at the time the systems were widely available 1.61 had some bugs with drives other than IBM 1.0GB (particularly with the Maxtor MXT-540S in the "small" array configuration).

1.62
   Contained information used by the 90MHz upgrade board - it is mandantory if your 95A uses the "big" platform. (Ed. P90 complex?)

1.63
   The Passplay sometimes set drives into "DDD" (Dead) state when they failed to come on ready in a very, very short period of time after power on. 1.63 should fix problems with the DFHS 2GB drives (later microcodes - successor of the 0664) and the "dead drive" symptom.  As far as I recall IBM recommended to use this code in all machines that have more than 3 drives installed and the Pentium platforms (My guess: problems with the power supply and signalling problems caused by DC-ripples). From 1.63 on you could use the same RAIDADM and the later ServerGuide Raid Manager for both adapters. Previous versions seemed to have delivered slightly odd codes that caused confusion.

1.99
   IBM announced the code "out of blue sky" and I wondered why, because the Passplay was already discontinued at that time. The 1.99 codes contained some fixes for "other systems" than the 95A. It was the last code announced for the Passplay.

Complex BIOS Requirements
   There are however some dependencies between the Raid-adapter microcode and that of the complex. You should not run the Raid with a complex BIOS below 03. The BIOS 10 has been announced to fix Y2K problems with OS/2 AFAIK. If you flash the complex to10 and keep the old Raid microcode you might run into problems. It should be 1.63 at least - especially if you have the P90 platform, which appears to the Raid microcode as Server 500 with the differing backplane layout - the return codes to the RAIDADM then might not reflect the "real" position of the drives on the backplane. 

LVD on Passplay
>What kind of drives does the RAID take? Is FAST/WIDE 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 Fast / Wide 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.