SSA Adapters

@8F97.ADF IBM SSA RAID Adapter

195-236 IBM SSA 4-Port Adapter for RISC System/6000
195-298 IBM SSA 4-Port Adapter Enhancements and Related Features for RISC System/6000

SA33-3270-02 Micro Channel SSA RAID Adapters Technical Reference (PDF)
SA33-3272-02 SSA Adapters User’s Guide and Maintenance Information (PDF)
SC23-1782-00 IBM Enhanced SSA 4-Port Adapter User's Guide and Reference (PDF)

SA33-3270-02 Micro Channel SSA RAID Adapters Technical Reference (BOO)
SA33-3272-02 SSA Adapters: User's Guide and Maintenance Information (BOO)
S31H-8612-01 SSA Adapters: Technical Reference (BOO)
SG24-5750-00 Understanding SSA Subsystems in Your Environment (BOO)

IBM SSA Adapter Documentation Page (archived)

SSA Adapter Overview
SSA Port Header Pinout
SSA 9-Pin Mini-Ports
SSA Unitized Connector
Fibre-Optic Extender
PCI vs MCA Drivers

Note: This page describes the different IBM pSeries SSA adapters.

SSA Adapter Overview

FC ID FRU Name Bus Max / loop Name
6214 4-D   SSA Adapter MCA 2 Mayflower
6215 4-N   SSA Enhanced RAID Adapter
Multi-Initiator RAID/EL Adapter
PCI 4 (R-5)
8 (R-0)
Campbell 2
6216 4-G 89H5667 SSA Enhanced Adapter MCA 8 Mayflower 2
6217 4-I 96H9883 SSA 4-Port RAID Adapter MCA 1 Sarratoga
6218 4-J   SSA RAID Adapter PCI 1 Beaulieu
6219 4-M   SSA Enhanced RAID Adapter [P]
Multi-Initiator RAID/EL Adapter
MCA 4 (R-5)
8 (R-0)
6225 4-P   Advanced SerialRAID Adapter PCI 2 (R-5)
8 (R-0)
Santa Cruz
6230 4-P   Advanced SerialRAID Plus Adapter PCI 2 (R-5)
8 (R-0)
Santa Cruz

Note: All MCA adapters use devices.mca.8f97.*, does this mean that they are all similar?

Notes: The 6215 and 6219 adapters appear to be essentially identical other than the fact that the 6215 is PCI and the 6219 is MCA (they both take the same microcode and appear to have identical functionality).

Availability of TMSSA support may depend on what version of microcode is on the adapter (the 6215 and 6219 adapters require at least level 1801).

The Advanced SerialRAID Adapters (6225 and 6230) are capable of 40 MB/sec per direction per loop. The other adapters are capable of 20 MB/sec per direction per loop.

Many of the values in the above table assume that the adapter has sufficiently current microcode.

The Advanced SerialRAID Plus Adapter Planning Guide states:

"The Advanced SerialRAID Plus Adapter has code above level 7600. The Advanced SerialRAID Adapter had code below 7600 and that adapter can be converted to support the additional functions by downloading code above level 7600."

i.e. the adapters are identical if they have sufficiently recent microcode. This would seem to explain why the 6225 and the 6230 both are type 4-P.

J2, J6 - Internal SSA Connectors

The adapter card has 2 internal SSA connectors and 4 external connectors. This allows one of the 2 dual-port SSA nodes to be connected either internally or externally to the system unit. The internal connectors are 2 x 3 pin SSA connectors.

Ports B1 and B2 have both internal and external connectors. The marking also indicates that ports A1 and A2 are paired, that is, they are connected to the same SSA loop interface chip. Similarly, ports B1 and B2 are paired.

+5 V power is available on the connector to power an external optical extender.

SSA Port Header Pinout

Thanks to David Ress for finding this after I lost the reference... Pin 1 is marked on the outside of the header on the PCB.

Pin Signal Pin Signal
1 Line Out+ 6 Line Out-
2 Ground 5 Ground
3 Line In- 4 Line In+

J14 Exploration

Dave Ress tips back his miner's helmet and says:
   I checked the SSA adapter I have, and it has the solder pads for a 6-pin port, but that is all. Looking at the A side and numbering the solder pads from left to right, I find:

Pad 1 - GND
Pad 2 - Pin 5 of U7
Pad 3 - Pin 4 of U7
Pad 4 - Pin 3 of U7
Pad 5 - Pin 6 of U7
Pad 6 - +5 V

Looking at the SCC2691AC1A28 datasheet and application note we learn that U7 is a UART, so the PS/2 port is really a serial port as the pins of U7 are mapped as:

Pin 3 - RxD
Pin 4 - TxD
Pin 5 - MPO => multi-purpose output (clock pulse?)
Pin 6 - MPI => multi-purpose input (clock pulse?)

Beyond that, I have no idea where the U7 chip interfaces to. I tried to map D0-7, but no luck there.

SSA 9-Pin Mini-Ports

SSA connectors are 9-pin high-density shielded ITT-Canon Micro MDSM connectors.

Pin Signal Pin Signal
1 Ground 6 Line Out+
2 Line Out- 7 Reserved/NC
3 Ground 8 +5 V
4 Line In- 9 Line In+
5 Ground

The serial ports conform to SSA, Level 1. Each port operates at 20MB/sec full duplex, using point-to-point copper cables up to 25 meters long.

SSA Drive Connectors

David Ress started diddling and said:
   I took one of my SSA drives carriers apart this morning. It originally went into a 7133.

I did this for two reasons: first, I have always wondered how to connect an internal SSA drive up to the B1 and B2 internal connectors. Second, if the SSA adapter has just a six pin ribbon connector, I was curious what the physical connector looked like on the SSA drive.

In looking at the SSA drive carrier, the first thought was "what in the world?", as the SSA drive carrier has a EURO 72-Pin style connector (think mini-Nubus). 72-pin connector to support a 6 pin ribbon connector? But, as it turns out, 32 of the pins are no-connect.

Further disassembling the SSA drive carrier revealed a IBM DFHC 4.5GB drive, made in 1996. Note: the SSA drive carrier has a label that says assembled on 23 Feb 2000, I guess IBM had many units left over.

In removing the DFHC I learned that the connector is very unusual, unlike anything I have seen before. I guess I was hoping to see a SCSI-2 connector as SSA is a superset of the SCSI-2 protocol, but that was very much wishful thinking on my part.

SSA Unitized Connector

SSA Unitized Connector

SSA Port on Unitized Connector

Option Port on Unitized Connector

Power Port on Unitized Connector

Carrier Connector

4x32 female contact, BERG HPC connector, part number 99F9429. Ed. There seems to be different models with different carrier interfaces (at least for the 4-G adapter). YMMV.

Fibre-Optic Extender

A fibre-optic extender is available to connect an industry-standard fiber optic cable within an SSA loop when that loop is used with a 7133 SSA Disk Subsystem. With a fibre-optic extender attached at each node, the distance between them can be up to 2.4 km. The maximum sustainable data-transfer rate in a single direction on an SSA link is approximately 18 MB/s. Extending the link with a fiber optic cable results in no degradation of this data-transfer rate for lengths up to 200 meters, and a gradual reduction in the achievable data-transfer rate beyond this distance. This data-transfer rate reduction generally has no effect on SSA subsystem performance for most applications.

PCI vs MCA Drivers

> Dave, are the PCI and MCA variants of the SSA adapter close enough for the PCI drivers to work?

From my experiences in developing various drivers for MCA adapters under NT, I will answer "no."  This is due to the different way drivers scan their expansion buses for adapters. PCI drivers scan completely different from the way MCA drivers do. Some drivers, like the one I am working on with Ryan A., are written smart enough to scan multiple buses (in this case, it scans ISA, EISA, MCA, and PCI), but I have found that to be extremely rare.

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