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Japanese SCSI Adapters

SCSI adapter by Hiroshi Yamashita (old version)

16-bit SCSI Adapters w/o Cache
   Short SCSI A/16 (SIP Terminators)
   Short SCSI A/16 (DIP Terminator)
   2/3 Length SCSI/A (50-pin Header + Card Edge)
32-bit SCSI Adapters w/ Cache
   Short SCSI A/32 with Cache (SIP Terminators)
   Short SCSI A/32 with Cache (DIP Terminator)
   2/3 Length SCSI with Cache (50-pin Header)
   Long SCSI A/32 with Cache and 2.5" HD
SCSI Investigation

Content by Tatsuo "Sandy" Sunagawa and Tomáš "Major Tom" Slavotínek.

16-bit SCSI Adapters w/o Cache

16-bit busmaster SCSI adapters based around the SCSI Adapter/A ("Tribble") architecture. The main difference is the smaller form factor of the Japanese adapters.

Later SCSI A/16 adapters replace the AIC-6250EL and 15F7917 pair with the 84F8324 SCSI bus controller.

Short SCSI A/16 (SIP Terminators)

P/N 07G3169

Short version of uncached SCSI /A with AIC6250EL and old SCSI microcode set.
Long uncached SCSI /A was equipped in PS/55 5570 (analogous to 8580 25 MHz).
I think this short card was an option for 5530-U/V but I'm not sure.

The serial diagnostic port is wired to the external SCSI connector. Specifically, pin 58 - GND, pin 59 - RXD, pin 60 - TXD. The port can be used to access the Serial Console.

Short SCSI A/16 (DIP Terminator)

P/N 35G2976 |
P/N 66G1080, FCC ID ANOTPS |

U8 Intel 80C32GB - 10 MHz microcontroller as busmaster CPU.
RN1 Resistor pack (term.) - Bourns 4120R-003 221/331 - Dual Terminator 220 Ω / 330 Ω
RT1 Polyfuse - Littelfuse 100 HG9K

Pads for 6-pin diag. header; From left to right, the pinout is: CHR, ITS, BRN, TXD, RXD, GND. The port can be used to access the Serial Console.

This adapter was sold worldwide with some PS/2 machines.

The short card (with microcode dated 1993 and later) can handle drives >1GB.

The BIOS (92F2244 and 92F2245) is the same as used on the "later" cached SCSI Adapter so it can support IML drives up to 3.94GB.

2/3 Length SCSI/A (50-pin Header)

P/N 79F1140 |

U1 SCSI microcode 84F8233 - M5M27C256AFP-15 32Kx8 OTP ROM (socketed SOIC/SOP-28)
U2,3 SCSI BIOS Even/Odd 64F4376/64F4377 M5M27C256AFP-15 32Kx8 OTP ROM (socketed SOIC/SOP-28)

2/3 Length uncached SCSI for 5560-W0. This one has 2 internal connectors, one is 50-pin flat ribbon cable connector and the other is 50-pin edge card connector.

Together with the cached P/N 95F4488 these are probably the only MCA SCSI adapters from IBM that have the standard 50-pin internal header. Both used in various 5560 machines plugged into one of the 2/3 length slots.

The serial diagnostic port is wired to the external SCSI connector. Specifically, pin 58 - GND, pin 59 - RXD, pin 60 - TXD. The port can be used to access the Serial Console.

32-bit SCSI Adapters w/ Cache

32-bit busmaster SCSI adapters based around the SCSI Adapter w/ Cache ("Spock" & "Spock Prime") architecture. The main difference is the smaller form factor of the Japanese adapters.

Later SCSI A/32 adapters replace the AIC-6250EL and 15F7917 pair with the 84F8324 SCSI bus controller.

Short SCSI A/32 with Cache (SIP Terminators)

P/N 07G3063 | |

Pads for a 7-pin diagnostic SMD connector; From left to right, the pinout is: +5, ITS, BRIN, CHRST, TXD, RXD, GND. The port can be used to access the Serial Console.

Short SCSI A/32 with Cache (DIP Terminator)

P/N 35G2818 |

This is the Latest SCSI A/32, probably an option for 5551-Rxx. Basically this adapter is capable to handle drive >1G. Unfortunately most of PS/55s (except 9595 and 8595-J) can't handle IML drive larger than 1G with this adapter due to BIOS issue. 8595-Jxx (1S1P planar with Type 3 50 MHz complex) with this adapter can handle HD over 1 GB as IML drive. SCSI ID for IML drive is not restricted to #6 for this combination.

Pads for a 7-pin diagnostic SMD connector; From left to right, the pinout is: +5, ITS, BRIN, CHRST, TXD, RXD, GND. The port can be used to access the Serial Console.

I once fried the F1 fuse when I attached a Rancho's Single/Differential converter. Really got shocked because that was the only one "> 1 GB capable card" I had back then. I trolled around parts shops in Akihabara and got a similar type of tiny chip named "Poly switch". Electrical specification was a bit different but with the chip my card revived.

2/3 Length SCSI with Cache (50-pin Header)

P/N 95F4488 | |

This adapter is an earlier version of SCSI A/32 and was equipped in 5561-W1x/W2x models. SCSI microcode set is 64F4356/57 and it can't handle drive > 1 GB as ID6.

Together with the uncached P/N 79F1140 these are probably the only MCA SCSI adapters from IBM that have the standard 50-pin internal header. Both used in various 5560 machines plugged into one of the 2/3 length slots.

The serial diagnostic port is wired to the external SCSI connector. Specifically, pin 58 - GND, pin 59 - RXD, pin 60 - TXD. The port can be used to access the Serial Console. It's also available on the three internal test points located above the 50-pin SCSI header. Specifically, TP1 - RXD, TP2 - GND, TP3 - TXD.

Long SCSI A/32 with Cache and 2.5" HD

P/N 35G3785

All chips on the PCB are same with short SCSI A/32 with cache P/N 35G2818 with Yellow DIP Terminator. Just the parts are reallocated on the PCB.

2.5" SCSI HD is mounted on the adapter. The drive is set to ID #6. The stock HD is WDS280 (80 MB).

SCSI Investigation

I'm not sure if I'm correct or totally wrong about the following info. I tested and experienced by myself thus I wrote. I can't explain my experience logically 'cause I can't read BIOS or don't have sufficient documentation about PS/55's SCSI feature.

It is told that PS/55's BIOS lacks, unfortunately, support for over 1 GB IML drive. Even if we use 92F2244/92F2245 SCSI BIOS and 10G4890 microcode, PS/55s such as 5580, 5560 and 5551-N can not accept IML drive larger than 1G capacity. Server models like 9595 (Type 4), 8595 (Type 3) and 9585 are capable to run drives > 1 GB as IML and they are basically same with pure PS/2. In another word, BIOS ROM in Japanese localized processor complexes (and planar) are not sufficient to take drives > 1 GB as it's IML drive even though we use SCSI adapters with enhanced SCSI code. We have such nice cards over here but it's true. It's ridiculous and sad.

Group A Adapters – not capable to handle > 1 GB IML and/or boot drive

Group B Adapters – capable to handle > 1 GB IML and/or boot drive

* Not capable to handle partition > 1 GB as a boot drive. Ed. Huh? But the title says "capable".

Flat package. Don't know correct term for the ROM. It's a flat, SOJ type ROM (write-one-time).

Example:

5580-Y with Type A Upgrade complexes (DX2-66), HD; Seagate ST42400N. Can't make system partition on the Seagate even with an adapter listed under Group B. The Seagate drive IDed as 6 off from 35G2818 can't be recognized as valid drive for IML.

If I use a smaller drive with ID=6 and make system partition on it, then change boot order to Seagate 2G in one partition as C, then system works. Here, if I change SCSI /A to listed under Group A, system stops upon booting with error message "Missing Operating System". If I change older type of SCSI /A to newer one again such as 35G2818 or 07G3063, every thing works fine.

If I change Type A Upgrade to Type 3, the Seagate drive off from 35G2818 and 6451280 (both in Group B) works fine as like as usual PS/2 with Type 3 platform. Also I can give SCSI ID other than 6 to ST42400N.

Conclusion (If I'm correct):

1. Pure PS/55s don't contain SCSI code in their BIOS or lack some important code relating SCSI. Server models (5580 and 5560) may handle drives larger than 1 GB if BIOS ROM could be replaced. IBM Japan had not ever released such BIOS ROMs nor reference diskettes.
2. SCSI adapters listed in group A can not handle drive larger than 1 GB for IML purpose. Also it can't boot OS even IML drive is smaller than 1 GB and boot order is changed to another drive larger than 1 GB in which OS is installed.
3. SCSI Adapters listed in group B can handle drive larger than 1 GB for IML purpose only when it is used with PS/2 complexes including PS/55 Type 3. In this case SCSI ID for IML drive is not limited to ID 6. With Japanese Type 1/2 and dx2-66 upgrades, SCSI adapters in group B on 5580/5560 can't do it.
4. As a matter of fact, 5551-N can not handle drives larger than 1 GB as an IML drive even though it has 92F2246/2247 microcode set on the planar.

Why Big Blue Japan deleted SCSI code from machine BIOS?