Difference between revisions of "RM02/03 disk drive"

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m (Jnc moved page RM02 disk drive to RM02/03 disk drive: Better naming system)
m (→‎External links: +RM02/03 Disk Subsystem User's Guide; new cats)
 
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The '''RM02''' was a 67MB [[MASSBUS]] [[disk]] [[pack]] [[drive]], 806 KB/s transfers, 42.5 ms average access time, 6 ms [[track]]-to-track [[seek]] time, 2400 rpm
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{{Infobox Disk drive
 +
| name = RM02/RM03
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| manufacturer = [[Digital Equipment Corporation]]
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| controller = [[RH10 MASSBUS controller|RH10]] ([[PDP-10]])<br>[[RH20 MASSBUS controller|RH20]] ([[KL10]])<br>[[RH11 MASSBUS controller|RH11]] ([[UNIBUS]])<br>[[RH70 MASSBUS controller|RH70]] ([[PDP-11/70]])<br>[[RH780 Massbus Adapter|RH780]] ([[VAX-11/780]])<br>[[RH750 Massbus Adapter|RH750]] ([[VAX-11/750]])
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| capacity = 67 Mbytes
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| transfer rate = 2.48 μsec/word (RM02/16-bit)<br>2.79 μsec/word (RM02/18-bit)<br>1.65 μsec/word (RM03/16-bit)<br>1.86 μsec/word (RM03/18-bit)<br>
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| average access time = 42.5 msec (RM02)<br>38.3 msec (RM03)
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| rpm = 2400 (RM02)<br>3600 (RM03)
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| revolution time = 25.9 msec (RM02)<br>17.3 msec (RM03)
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| one track seek = 6 msec
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| average seek = 30 msec
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| maximum seek = 55 msec
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| surfaces = 6 (5 data, 1 servo)
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| tracks = 823<!-- (nominally 400 plus 6 spares; many systems used all 406, as reliability was high) -->
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| sectors = 30 (18-bit words)<br>32 (16-bit words)
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| words per sector = 256
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<!-- | tracks per inch = 100 -->
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<!-- | density = 2200 bpi (maximum) -->
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| recording method = [[Modified Frequency Modulation|MFM]]
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| physical size = 21-5/8?" W x 39" H x 33" L
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| weight = 430 pounds
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<!-- | power consumption = 660 VA per phase (running); 3300 VA per phase(starting) -->
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}}
  
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{{stub}}
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The '''RM02''' and '''RM03''' were [[MASSBUS]] large [[removable-pack disk]]s. They were effectively identical, except that the RM03 rotated faster (3600 RPM, versus 2400 RPM for the RM02). The RM02 provided 806 KB/s transfers; the RM03 was 1200 KB/s transfers.
  
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[[Category: MASSBUS Devices]]
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Both supported both 15-bit and 18-bit [[word]]s; user data is protected by a 32-bit [[error-correcting code|ECC]] per [[sector]]. RM0x drives are dual-ported, allowing any drive to be attached to two different controllers. Generally a maximum of 8 drives were supported per [[device controller]].
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[[Category: DEC Disk Drives]]
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 +
They both used 5-[[platter]] RM03P (type 9877) [[pack]]s; neither side of the top and bottom platters were used, however - they were only there for protection. Of the other 6 surfaces, one was read-only,  pre-recorded by the manufacturer with servo information; the drive had the capability of seeking to a 200 μinch offset under command, to allow the attempted recovery of otherwise-unreadable data.
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==Registers==
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As usual with MASSBUS devices, most device-specific [[register]]s are actually in the device; the MASSBUS interface to the host computer only contains generic registers. In the RM02/03, the host's MASSBUS [[device controller]] contains a small number of registers (5 in the [[RH11 MASSBUS controller||RH11]]), and the drive contains 16. They are:
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{| class="wikitable"
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! Name !! MASSBUS Address !! Function
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|-
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| RMCS1 Control || 00 || Function code, GO
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|-
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| RMDA Desired Sector/Track Address || 05
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|-
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| RMDS Drive Status || 01 || Non-error status
 +
|-
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| RMER1 Error 1 || 02
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|-
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| RMAS Attention Summary || 04 || One bit per drive
 +
|-
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| RMLA Look-Ahead || 07 || Current sector
 +
|-
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| RMMR1 Maintenance 1 || 03
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|-
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| RMDT Drive Type || 06
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|-
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| RMSN Serial Number || 10 || Low 4 digts
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|-
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| RMOF Offset || 11 || 1 bit head offset
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|-
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| RMDC Desired Cylinder || 12 || For seek
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|-
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| RMHR Holding || 13 || Unused; zeros
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|-
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| RMMR2 Maintenance 2 || 14
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|-
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| RMER2 Error 2 || 15
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|-
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| RMEC1 ECC Position || 16
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|-
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| RMEC2 ECC Pattern || 17
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|}
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{{semi-stub}}
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==External links==
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* [http://www.bitsavers.org/pdf/dec/disc/rm03/ RM02/03 Documents]
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** [http://www.bitsavers.org/pdf/dec/disc/rm03/EK-RM023-TD-001_RM02_03_Tech_May78.pdf RM02/03 Adapter Technical Description Manual]
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** [http://bitsavers.org/pdf/dec/disc/rm05/RM05_Handbook.pdf RM02/03/05 handbook]
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* [https://manx-docs.org/collections/antonio/arc-db/EK-RM02-UG-002.pdf RM02/03 Disk Subsystem User's Guide] (EK-RM02-UG-002)
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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 Removable-pack Disks]]

Latest revision as of 16:08, 15 August 2023


RM02/RM03
Manufacturer: Digital Equipment Corporation
Drive Controller(s): RH10 (PDP-10)
RH20 (KL10)
RH11 (UNIBUS)
RH70 (PDP-11/70)
RH780 (VAX-11/780)
RH750 (VAX-11/750)
Capacity: 67 Mbytes
Transfer Rate: 2.48 μsec/word (RM02/16-bit)
2.79 μsec/word (RM02/18-bit)
1.65 μsec/word (RM03/16-bit)
1.86 μsec/word (RM03/18-bit)
Average Access Time: 42.5 msec (RM02)
38.3 msec (RM03)
Revolutions per Minute: 2400 (RM02)
3600 (RM03)
1/2 Revolution Time: 25.9 msec (RM02)
17.3 msec (RM03)
One Track Seek Time: 6 msec
Average Seek Time: 30 msec
Maximum Seek Time: 55 msec
Total Surfaces: 6 (5 data, 1 servo)
Tracks per Surface: 823
Sectors per Track: 30 (18-bit words)
32 (16-bit words)
Words per Sector: 256
Recording Method: MFM
Physical Size: 21-5/8?" W x 39" H x 33" L
Weight: 430 pounds


The RM02 and RM03 were MASSBUS large removable-pack disks. They were effectively identical, except that the RM03 rotated faster (3600 RPM, versus 2400 RPM for the RM02). The RM02 provided 806 KB/s transfers; the RM03 was 1200 KB/s transfers.

Both supported both 15-bit and 18-bit words; user data is protected by a 32-bit ECC per sector. RM0x drives are dual-ported, allowing any drive to be attached to two different controllers. Generally a maximum of 8 drives were supported per device controller.

They both used 5-platter RM03P (type 9877) packs; neither side of the top and bottom platters were used, however - they were only there for protection. Of the other 6 surfaces, one was read-only, pre-recorded by the manufacturer with servo information; the drive had the capability of seeking to a 200 μinch offset under command, to allow the attempted recovery of otherwise-unreadable data.

Registers

As usual with MASSBUS devices, most device-specific registers are actually in the device; the MASSBUS interface to the host computer only contains generic registers. In the RM02/03, the host's MASSBUS device controller contains a small number of registers (5 in the |RH11), and the drive contains 16. They are:

Name MASSBUS Address Function
RMCS1 Control 00 Function code, GO
RMDA Desired Sector/Track Address 05
RMDS Drive Status 01 Non-error status
RMER1 Error 1 02
RMAS Attention Summary 04 One bit per drive
RMLA Look-Ahead 07 Current sector
RMMR1 Maintenance 1 03
RMDT Drive Type 06
RMSN Serial Number 10 Low 4 digts
RMOF Offset 11 1 bit head offset
RMDC Desired Cylinder 12 For seek
RMHR Holding 13 Unused; zeros
RMMR2 Maintenance 2 14
RMER2 Error 2 15
RMEC1 ECC Position 16
RMEC2 ECC Pattern 17

External links

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