IML/Boot Limits of Passplays

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.

Cheetah LED
   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.

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. The bigger the cache the bigger the damage if the controller chokes and cannot write back the data to the drives. Large caches on Raid controllers make only sense if they are battery-backed 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. You should be aware of the fact that 4MB of cache memory contain a large number of "data-stripes" (usually 8K blocks).
   These will inadvertantly get lost if the machine powers down by what reason, when the controller gets defective 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.

On the other hand: the size of the cache depends on
a) the overall data-throughput of the drives (buffering x accesses while the drives are in *mechanically* causes delay / dead zone / recalibration)
b) the size of the data-stripes (8K normally - 64K under WinNT might give better results)
c) the operating system (WinNT and OS/2 are very "swap active")
d) the 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) the 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. 

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.

CAUTION!!!
   The only thing they differ is the microcode, which *may not* be interchanged. The SR95 adapter uses a microcode-level 1.6x and (latest) 1.99, the 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)

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.

SCSI-2 RAID Controller  "Passplay" FRU 92F0335
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)

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

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. From 1.63 on you could use the same RAIDADM and the later ServerGuide Raid Manager for both adapters ... the previous versions seemed to have delivered slightly odd codes
that confused mainly.

   The Passplay was known for some misbehaviour to set drives into "DDD" (Dead) state when they failed to come on ready in a very, very short period of time after power on. This had beed fixed with the 1.63 code for most drives. The 1.99 codes contained some fixes for "other systems" than the 95A. It was the last code announced for the Passplay.

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

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

1.62 contained informations used by the 90MHz upgrade board - it is mandantory if your 95A uses the "big" platform. 

1.63 finally 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).

Then IBM announced the 1.99 code "out of blue sky" and I wondered why, because the Passplay was already discontinued at that time.
   There are however some dependencies between the Raid-adapter microcode and that of the processor board. You should not run the Raid with a codelevel below 3 for the processor platform. The last codelevel 10 has been announced to fix Y2K problems with OS/2 AFAIK. If you flash the processor platform to 10 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. 

There is NO external port on the Passplay!

Notes:
   The 28 pin 8Kx8 NVSRAM is a Benchmarq, bq4010YMA-200, Spec sheet
Cable Parts of note: 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.

Slots Passplay will Fit
  The Passplay is an RS6000 form factor card (it's big). There are cutouts in 8595, 9595, and 95A cases that will allow the edge of the card at the bracket end to fit. Thanks to Dennis Smith, I was turned on to them.
   Slots 2, 3, and 4 have these cutouts- The 8595s do not have a cushion in them, the 95As do.

IBM or Generic SIMMs?
   The 30-pin Simms should be standard industrial ("generic") parts. Since the original concept allowed to go for 4 x 1, 4 x 4 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 their list.
 

SCSI type	SCSI-2 Fast/Wide
SCSI bus path / speed	16 bit / 20 MB/sec
I/O bus path / speed	32 bit / 40 MB/sec streaming
I/O features	Streaming data transfer
	Address parity and data parity
RAID levels	RAID 0, 1,  Hybrid 1, 5
	4 ind (A, B, C, D)  / 8 logical arrays
Tagged Command Queuing	Yes
Processor	i960 at 25 MHz
Size	Type 5 (only fits Model 85 or 95)
Channels	Two (both internal)
Connectors	Two internal only
Devices supported	7 devices per adapter
Cache std / max	4 MB / 64 MB (with parity)
Cache method	4 sockets for 30 pin 80ns SIMMs
Cache configurations	4 16 or 64 MB only
Cache write policy	Write-through or write-back
Available / withdrawn date	N/A (Nov 1993 for Servers)

SCSI-2 Fast/Wide Streaming RAID Adapter/A  "Cheetah" FRU 06H3059
                                                                                                  Sidecard FRU 06H3060
194-170 19940517 IBM SCSI-2 Fast/Wide Streaming-RAID Adapter/A
FWSR Features
FWSR Flash BIOS 2.21
FWSR Flash BIOS Readme

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

J1 Channel 1 68 pin edgecard J2 Channel 2 68 pin edgecard J3 Not connected. Or used. J4 DASD Status Connector J5 DASD Status Connector J6 Possible serial port. Unused.

J9 Channel 2 external port. Y1 50 MHz Oscillator Y2 40MHz Oscillator F1 Channel 2 PTC resistor F2 Channel 1 PTC resistor

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

Function of the NVSRAM
  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.

 Problem Isolation Aids : The system is an 8640, 8641, 8642 or 3518 with one or more hot swap backplanes installed.
Fix :
    Check the Backplane Address Jumper:
 1. Shutdown the operating system
 2. Power off the server.
 3. Verify the Backplane Address Jumper configuration:
       a. For ALL 8640 and 8641 backplanes: Jumpers should NOT be present on the pins for Bank0, Bank1, or Bank2 on any backplane. Refer to Figure 1. The PC Server 520 (8641) may have shipped with a backplane address jumper installed; it should be removed.
       b. For 8642 and 3518 backplanes: Each backplane MUST have a unique address. A jumper should be present on the pins for Bank0, Bank1, OR Bank2 depending on the backplane's location within the server or expansion enclosure. Refer to Figure 1 and Table 1 below to determine the correct jumper setting for an 8642 or 3518 backplane:

 Figure 1

                                       Backside of Backplane
                    .------------------------------------------------------------.
                    |           -----                                     -----  |
                    |           |   |                                     |   |  |
                    |           | S |                                     | S |  |
                    |.. Bank2   | C |                                     | C |  |
                    |.. Bank1   | S |                                     | S |  |
                    |.. Bank0   | I |                                     | I |  |
                    |           |   |                                     |   |  |
                    |           -----                                     -----  |
                    --------------------------------------------------------------

Table 1

Jumper Position	Backplane Location
Bank0	Bank C
Bank1	Bank D
Bank2	Bank E

Note :
    The documentation in the Server 520 User's Handbook, part number 62H7096, page 177 is incorrect. Backplane address jumpers should NOT be installed on any Server 520 backplanes.

Cheetah in a Server 500

SCSI ID Jumper
      If two backplanes are connected to the same adapter, one backplane must be set to high and the other one to low.

SCSI ROM Address ID Jumper Setting	Description
HI=High	Assigns SCSI IDs 8 to D to the  backplane
LO=Low	Assigns SCSI IDs 0 to 5 to the backplane

ROM Address Jumper Setting

 Notes
     a. If more than one backplane is installed in the computer, each backplane must have a different ROM address setting.
   b. Do not install a ROM address jumper on backplanes installed in PC Server 320 computers.
 c. To identify the location for the backplane jumper, see 'Hot-Swap Backplane (FRU No. 06H8388)´.

Jumper Position	Description
C	Address for a backplane installed in Bank C
D	Address for a backplane installed in Bank D
E	Address for a backplane installed in Bank E

Termination (Hot-Swap Back Plane)
  The hot-swap back plane is automatically terminated. Drives connected to the hot-swap back plane should not be terminated.