PA-RISC SCSI Storage
Overview
HP 9000 workstations and servers mostly used industry-standard SCSI storage devices and controllers. There was a wide range of versions of the SCSI bus specification implemented in a variety of controller chips since the 1980s.
The table lists some of the variants of SCSI found in PA-RISC computers.
| SCSI | Spec | Clock | Width | Data rate max |
Devices max |
Signals note* |
Length max |
Connector |
|---|---|---|---|---|---|---|---|---|
| Narrow SCSI | SCSI-1 | 5 MHz | 8-bit | 5 MB/s | 7 | SE | 6m | 50-pin |
| Fast-Narrow SCSI | SCSI-2 | 10 MHz | 8-bit | 10 MB/s | 7 | SE HVD |
3m 25m |
50-pin |
| Fast-Wide SCSI | SCSI-2 | 10 MHz | 16-bit | 20 MB/s | 15 | SE HVD |
3m 25m |
68-pin |
| Ultra-Narrow SCSI | SCSI-3 | 20 MHz | 8-bit | 20 MB/s | 7 | SE LVD HVD |
1.5m 12m 25m |
50-pin |
| Ultra-Wide SCSI | SCSI-3 | 20 MHz | 16-bit | 40 MB/s | 15 | SE LVD HVD |
1.5m 12m 25m |
68-pin |
| Ultra2-Wide SCSI | SPI-2 | 40 MHz | 16-bit | 80 MB/s | 15 | LVD | 12m | 68-pin |
| Ultra160 SCSI | SPI-5 | 40 MHz | 16-bit | 160 MB/s | 15 | LVD | 12m | 68-pin |
| Ultra320 SCSI | SPI-5 | 80 MHz | 16-bit | 320 MB/s | 15 | LVD | 12m | 68-pin |
* SCSI used different electrical interfaces for devices and cabling. SE is Single-Ended, HVD is High-Voltage-Differential and LVD is Low-Voltage-Differential. HVD devices and controllers must not be mixed with SE or LVD.
Controllers
HP 9000 workstations and servers from HP used common industry-standards SCSI controllers for drives and storage. These chips were often integrated into HP mainboards or implemented on plug-in cards for GSC and PCI buses.
| Chipset | Speed | Width | Data rate | Bus |
|---|---|---|---|---|
| NCR 53C700 | Narrow | 5 MB/s | GSC, HP-PB | |
| NCR 53C710 | Fast | Narrow | 10 MB/s | GSC, EISA |
| NCR 53C720 | Fast | Wide | 20 MB/s | GSC, PCI, HP-PB |
| Symbios 53C875 | Ultra | Wide | 40 MB/s | PCI |
| LSI 53C896 | Ultra2 | Wide | 80 MB/s | PCI |
HP Adapters
HP produced custom SCSI adapters boards for its PA-RISC computers, using third-party SCSI chips for different SCSI and host system buses.
| Part | Bus | Chip | SCSI | Signals | Boot | HP-UX |
|---|---|---|---|---|---|---|
| A2679A | EISA | 53C710 | Fast-Narrow | SE | no | 9.0-11i/32-bit |
| 25525A | EISA | 53C710 | Fast-Narrow | HVD | 8.05-10.20 | |
| 25525B | EISA | 53C710 | Fast-Narrow | HVD | 8.05-11.0/32-bit | |
| A2874-66005 | GSC | 53C720 | Fast-Wide | HVD | yes | 9.05/11.0 |
| A2969A | HSC | 53C720 | Fast-Wide | HVD | yes | 10.01-11i |
| A3644A | HSC | 53C720 | Fast-Wide | HVD | 10.20-11i | |
| A4107A | GSC | 53C720 | Fast-Wide | HVD | 9.05-11i/32-bit | |
| A4268A | GSC-M | 53C720 | Fast-Wide | HVD | yes | 9.05-11.0/32-bit |
| 27251A | HP-PB | |||||
| 28655A | HP-PB | 53C710 | Fast-Narrow | SE | yes | 10.01-11i |
| 28696A | HP-PB | 53C720 | Fast-Wide | HVD | yes | 10.01-11i |
| A4800A | PCI | 53C720 | Fast-Wide | HVD | yes | 10.2-11i |
| A4974A | PCI | 53C875 | Ultra-Wide | SE | yes | 10.20-11.0 |
| A4976A | PCI | 53C720 | Fast-Wide | HVD | yes | 10.20-11.0 |
| A4999A | PCI | 53C896 | Ultra2-Wide | LVD | yes | 10.20-11.0 |
| A5159A | PCI | 53C720 | Fast-Wide | HVD | yes | 10.20-11i |