RL01/02 disk drive

RL01
Manufacturer:	Digital Equipment Corporation
Drive Controller(s):	RL11 (UNIBUS)
Capacity:	5.2 Mbytes (formatted)
Transfer Rate:	512 Kbytes/sec 3.9 usec/word (peak)
Average Access Time:	67.5 msec
Revolutions per Minute:	2400
1/2 Revolution Time:	12.5 msec
One Track Seek Time:	15 msec
Average Seek Time:	55 msec
Maximum Seek Time:	100 msec
Head Switching Time:	8 msec (maximum)
Total Surfaces:	2
Tracks per Surface:	256
Sectors per Track:	40
Words per Sector:	128
Tracks per Inch:	125
Density:	3725 bpi (maximum)
Recording Method:	Modified Frequency Modulation (MFM)
Start Time:	40 seconds
Stop Time:	30 seconds
Physical Size:	19" W x 10-1/2" H x 25" L
Weight:	55 pounds
Power Consumption:	160W (running); 550 VA (starting)

An RL01

The RL01 is a 5MiB, single platter, removable pack disk drive introduced in 1976 by Digital Equipment Corporation. It used an IBM 5440 type pack, as used on the IBM System/3.

To keep the heads properly aligned on the tracks, it used a servo system driven by servo data written on the pack (along with sector headers) at the factory; packs cannnot be low-level re-formatted in the field.

RL01 drive

Early versions of the drive included a set of brushes that swing out over the platter on start-up; these were deleted in later versions.

The QBUS controllers are the RLV11 and RLV12, the latter being the Q22 version.

The RL02 is a higher density version, with twice as many tracks.