Difference between revisions of "RM02/03 disk drive"

From Computer History Wiki
Jump to: navigation, search
(+pack info)
(+Registers)
Line 18: Line 18:
 
<!-- | density = 2200 bpi (maximum) -->
 
<!-- | density = 2200 bpi (maximum) -->
 
| recording method = [[Modified Frequency Modulation|MFM]]
 
| recording method = [[Modified Frequency Modulation|MFM]]
−
| physical size = 33" W x 39" H x 21-5/8?" L
+
| physical size = 21-5/8?" W x 39" H x 33" L
 
| weight = 430 pounds
 
| weight = 430 pounds
 
<!-- | power consumption = 660 VA per phase (running); 3300 VA per phase(starting) -->
 
<!-- | power consumption = 660 VA per phase (running); 3300 VA per phase(starting) -->
Line 27: Line 27:
 
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]].
 
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]].
  
−
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 sides, 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.
+
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 [[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:
 +
 
 +
{| class="wikitable"
 +
! 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
 +
|}
  
 
{{semi-stub}}
 
{{semi-stub}}

Revision as of 17:02, 4 November 2020


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 multi-platter large moving-head disk pack drives. 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
Retrieved from "https://gunkies.org/w/index.php?title=RM02/03_disk_drive&oldid=22722"