Difference between revisions of "RM80 Disk Drive"

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[[Image:rm80.jpg|thumb|200px|right|RM80]]
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{{Infobox Disk drive
121 MB with [[MASSBUS]] interface, 1200 KB/s, 33.3 ms average access, 25 ms average seek, 6 ms track-to-track seek time, 3600 rpm
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| name = RM80
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| manufacturer = [[Digital Equipment Corporation|DEC]]
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| year introduced = October, 1980
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| controller = [[RH11 MASSBUS controller|RH11]], [[RH70 MASSBUS controller|RH70]], [[RH10 MASSBUS controller|RH10]], [[RH20 MASSBUS controller|RH20]], [[RH780 Massbus Adapter|RH780]], [[RH750 Massbus Adapter|RH750]]
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| capacity = 124 Mbytes
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| transfer rate = 1.2 Mbytes/sec
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| average access time = 33.3 msec
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| rpm = 3600
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| revolution time = 8.3 msec
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| one track seek = 6 msec
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| average seek = 25 msec
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| maximum seek = 50 msec
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| surfaces = 7 data, 1 servo
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| number of heads = 14 data,<br>1 servo (read-only)
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| tracks = 561 (18-bit word mode)<br>559 (16-bit word mode)
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| sectors = 30 (18-bit word mode)<br>31 (useable; 16-bit word mode)
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| words per sector = 256 (16-bit word mode)
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| tracks per inch = 478
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| density = 6339 (max; inner track)
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| recording method = [[Modified Frequency Modulation|MFM]]
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| start time = 20 secs (avg);<br>40 secs (max)
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| stop time = 9 secs (avg);<br>13 secs (max)
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| physical size = 26cm x 44cm x 67cm
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| weight = 135 lbs (approx)
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| power consumption = 575 watts
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}}
  
[[Category:DEC Disk Drives]]
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[[Image:rm80.jpg|thumb|200px|left|RM80]]
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The '''RM80 Disk Drive''' was a [[MASSBUS]] [[non-removable-media disk]] from [[Digital Equipment Corporation|DEC]]; it held 124 MB. It was apparently the MASSBUS version of the [[R80 Disk Drive]]; it could support either 16- or 18-bit words. It was internally operated by a [[microprocessor]] which used 32-bit burst [[error-correcting code|ECC]] to invisibly repair simple data errors.
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It had two heads per surface; not rotationally opposed (to halve maximum access time), but two on each arm; there were thus 1,122 usable tracks on each data surface (in 18-bit word mode; 4 tracks were reserved for maintenance purposes in 16-bit mode). 1 sector per track was reserved for bad block replacement in 16-bit word mode, out of 32 total.
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The RM80 can also be connected in a dual-[[hardware port|port]] arrangement, permitting its use by two [[device controller|controllers]].
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==Further reading==
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* ''RM80 Disk Drive Technical Description Manual'' (EP-0RM80-TD-001) - not available online, but in microfiche
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* ''RM80 Disk Drive Service Manual'' (EP-0RM80-SV-001) - not available online, but in microfiche
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==External links==
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* [https://manx-docs.org/collections/antonio/arc-db/RM80_Disk_Drive_Service_Manual_Preliminary.pdf RM80 Disk Drive Service Manual]
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* [http://www.bitsavers.org/pdf/dec/disc/rm05/EK-RMADA-TD-001_Oct80.pdf RM MASSBUS Adapter Technical Description Manual] (EK-RMADA-TD-001)
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[[Category: MASSBUS Disk Drives]]
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[[Category: DEC Non-removable-media Disks]]

Latest revision as of 16:23, 18 August 2023


RM80
Manufacturer: DEC
Year Introduced: October, 1980
Drive Controller(s): RH11, RH70, RH10, RH20, RH780, RH750
Capacity: 124 Mbytes
Transfer Rate: 1.2 Mbytes/sec
Average Access Time: 33.3 msec
Revolutions per Minute: 3600
1/2 Revolution Time: 8.3 msec
One Track Seek Time: 6 msec
Average Seek Time: 25 msec
Maximum Seek Time: 50 msec
Total Surfaces: 7 data, 1 servo
Number of Heads: 14 data,
1 servo (read-only)
Tracks per Surface: 561 (18-bit word mode)
559 (16-bit word mode)
Sectors per Track: 30 (18-bit word mode)
31 (useable; 16-bit word mode)
Words per Sector: 256 (16-bit word mode)
Tracks per Inch: 478
Density: 6339 (max; inner track)
Recording Method: MFM
Start Time: 20 secs (avg);
40 secs (max)
Stop Time: 9 secs (avg);
13 secs (max)
Physical Size: 26cm x 44cm x 67cm
Weight: 135 lbs (approx)
Power Consumption: 575 watts


RM80

The RM80 Disk Drive was a MASSBUS non-removable-media disk from DEC; it held 124 MB. It was apparently the MASSBUS version of the R80 Disk Drive; it could support either 16- or 18-bit words. It was internally operated by a microprocessor which used 32-bit burst ECC to invisibly repair simple data errors.

It had two heads per surface; not rotationally opposed (to halve maximum access time), but two on each arm; there were thus 1,122 usable tracks on each data surface (in 18-bit word mode; 4 tracks were reserved for maintenance purposes in 16-bit mode). 1 sector per track was reserved for bad block replacement in 16-bit word mode, out of 32 total.

The RM80 can also be connected in a dual-port arrangement, permitting its use by two controllers.

Further reading

  • RM80 Disk Drive Technical Description Manual (EP-0RM80-TD-001) - not available online, but in microfiche
  • RM80 Disk Drive Service Manual (EP-0RM80-SV-001) - not available online, but in microfiche

External links