RA82 disk drive: Difference between revisions
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[[ | {{Infobox Disk drive | ||
| name = RA82 | |||
| manufacturer = [[Digital Equipment Corporation|DEC]] | |||
<!-- | year introduced = 198x --> | |||
| controller = [[Standard Disk Interconnect#SDI Family of DSA Products|all SDI controllers]] | |||
| capacity = 622 Mbytes (formatted)<br>855 Mbytes (un-formatted) | |||
| transfer rate = 2.4 Mbytes/sec | |||
| average access time = 32.3 msec | |||
| rpm = 3600 | |||
| revolution time = 8.3 msec | |||
| one track seek = 6 msec | |||
| average seek = 24 msec | |||
| maximum seek = 38 msec | |||
| surfaces = 7 data, 1 data/servo (shared) | |||
| number of heads = 15 data,<br>1 servo (read-only) | |||
| tracks = 1423 (usable, per head)<br>1435 (total, per head) | |||
| sectors = 57 (usable)<br>58 (total) | |||
| bytes per sector = 512 | |||
| tracks per inch = 1063 | |||
| density = 12,545 | |||
| recording method = [[Modified Frequency Modulation|MFM]] | |||
| start time = 50 secs (max) | |||
| stop time = 20 secs (max) | |||
| physical size = 26cm x 44cm x 67cm | |||
| weight = 172 lbs | |||
| power consumption = 560 watts (idle) | |||
}} | |||
[[Image:ra82.jpg|thumb|200px|left|RA82s]] | |||
[[Category: | The '''RA82 disk drive''' is a [[Standard Disk Interconnect]] [[non-removable-media disk]] drive from [[Digital Equipment Corporation|DEC]]. It is member of the [[Digital Storage Architecture]]. A physically large drive (14-inch platters, in a heavy enclosure 10.5" x 16" x 36"), its capacity was 622 Mbytes. | ||
It had two heads per surface; not rotationally opposed (to halve maximum access time), but two on each arm; there thus 2,846 usable tracks on each data surface. It was internally operated by a pair of [[microprocessor]]s, which used 32-bit burst [[error-correcting code|ECC]] to invisibly repair simple data errors. An [[EIA RS-232 serial line interface|RS232]] port was provided for [[diagnostic]] purposes. | |||
The RA82 can also be connected in a dual-[[hardware port|port]] arrangement, permitting its use by two [[device controller|controllers]]. | |||
{{semi-stub}} | |||
==External links== | |||
* [http://bitsavers.org/pdf/dec/disc/ra82/ ra82] - documentation at [[Bitsavers]] | |||
** [http://bitsavers.org/pdf/dec/brochures/DEC-RA-FamilyOfWinchesterDiskDrives.pdf RA Family Of Winchester Disk Drives] - brochure | |||
* [http://wwcm.synology.me/pdf/EK-ORA82-UG-001%20RA82%20Disk%20Drive%20User%20Guide.pdf RA82 Disk Drive User Guide] (EK-0RA82-UG-001) | |||
[[Category: SDI Disk Drives]] | |||
[[Category: DEC Non-removable-media Disks]] | |||
Latest revision as of 01:12, 31 August 2023
| RA82 | |
| Manufacturer: | DEC |
|---|---|
| Drive Controller(s): | all SDI controllers |
| Capacity: | 622 Mbytes (formatted) 855 Mbytes (un-formatted) |
| Transfer Rate: | 2.4 Mbytes/sec |
| Average Access Time: | 32.3 msec |
| Revolutions per Minute: | 3600 |
| 1/2 Revolution Time: | 8.3 msec |
| One Track Seek Time: | 6 msec |
| Average Seek Time: | 24 msec |
| Maximum Seek Time: | 38 msec |
| Total Surfaces: | 7 data, 1 data/servo (shared) |
| Number of Heads: | 15 data, 1 servo (read-only) |
| Tracks per Surface: | 1423 (usable, per head) 1435 (total, per head) |
| Sectors per Track: | 57 (usable) 58 (total) |
| Bytes per Sector: | 512 |
| Tracks per Inch: | 1063 |
| Density: | 12,545 |
| Recording Method: | MFM |
| Start Time: | 50 secs (max) |
| Stop Time: | 20 secs (max) |
| Physical Size: | 26cm x 44cm x 67cm |
| Weight: | 172 lbs |
| Power Consumption: | 560 watts (idle) |
The RA82 disk drive is a Standard Disk Interconnect non-removable-media disk drive from DEC. It is member of the Digital Storage Architecture. A physically large drive (14-inch platters, in a heavy enclosure 10.5" x 16" x 36"), its capacity was 622 Mbytes.
It had two heads per surface; not rotationally opposed (to halve maximum access time), but two on each arm; there thus 2,846 usable tracks on each data surface. It was internally operated by a pair of microprocessors, which used 32-bit burst ECC to invisibly repair simple data errors. An RS232 port was provided for diagnostic purposes.
The RA82 can also be connected in a dual-port arrangement, permitting its use by two controllers.
External links
- ra82 - documentation at Bitsavers
- RA Family Of Winchester Disk Drives - brochure
- RA82 Disk Drive User Guide (EK-0RA82-UG-001)
