RA70 disk drive
From Computer History Wiki
| RA70 | |
| Manufacturer: | DEC |
|---|---|
| Drive Controller(s): | all SDI controllers |
| Capacity: | 280 Mbytes (formatted) 350 Mbytes (unformatted) |
| Transfer Rate: | 1.4 Mbytes/sec |
| Average Access Time: | 27 msec |
| Revolutions per Minute: | 4000 |
| 1/2 Revolution Time: | 7.5 msec |
| Average Seek Time: | 19.5 msec |
| Total Surfaces: | 11 data, 1 servo |
| Number of Heads: | 11 data, 1 servo |
| Tracks per Surface: | 1507 |
| Sectors per Track: | 34 |
| Bytes per Sector: | 512 |
| Tracks per Inch: | 1355 |
| Density: | 22,437 |
| Start Time: | 59 secs (avg) |
| Stop Time: | 15 secs (avg) |
| Physical Size: | 9cm x 14.6cm x 22.4cm |
| Weight: | 10.5 lbs |
| Power Consumption: | 264 watts (idle) |
The RA70 disk drive is a Standard Disk Interconnect non-removable-media disk drive from DEC. Unlike all the other RA-series drives, it is a compact width - 5.25 inches wide. It has no internal power supply; it gets its power from the host system, or its SA7x enclosure.
Its capacity was 280 Mbytes (formatted). It was internally operated by a microprocessor which used 32-bit burst ECC to invisibly repair simple data errors.
Further reading
- RA70 Disk Drive Technical Description Manual (EK–ORA70–TD) - not available online
- RA7x Disk Drive Service Manual (EK–ORA7X-SM) - not available online
External links
- RA Family Of Winchester Disk Drives - brochure
- RA7x/SA7x Pocket Reference Guide (EK–RSA7X–PG–002)
