Difference between revisions of "RM02/03 disk drive"

From Computer History Wiki
Jump to: navigation, search
(Add more info)
(+pack info)
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 ??" L
+
| physical size = 33" W x 39" H x 21-5/8?" 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) -->
 
}}
 
}}
  
The '''RM02''' and '''RM03''' were [[MASSBUS]] multi-[[platter]] large  moving-[[head]] [[disk]] [[pack]] [[drive]]s. They were effectively identical, except that the RM03 rotated faster (3600 RPM, versus 2400 RPM for the RM02). Both supported both 15-bit and 18-bit [[word]]s; user data is protected by a 32-bit [[error-correcting code|ECC]] per [[sector]].
+
The '''RM02''' and '''RM03''' were [[MASSBUS]] multi-[[platter]] large  moving-[[head]] [[disk]] [[pack]] [[drive]]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.
  
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]].
  
The RM02 provided 806 KB/s transfers; the RM03 had 1200 KB/s transfer.
+
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.
  
 
{{semi-stub}}
 
{{semi-stub}}

Revision as of 14:52, 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: 33" W x 39" H x 21-5/8?" 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 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.