RS03/04 disk drive
From Computer History Wiki
| RS03/RS04 | |
| Manufacturer: | Digital Equipment Corporation |
|---|---|
| Drive Controller(s): | RH11 (UNIBUS), RH70, RH10 |
| Capacity: | 512KB (RS03), 1024KB (RS04) |
| Transfer Rate: | 2 μsec/byte (RS03), μ1 sec/byte (RS04) |
| Average Access Time: | 8.5 msec (60Hz), 10.2 msec (50Hz) |
| Revolutions per Minute: | 3600 (60Hz) |
| Media: | 16" diameter nickel-cobalt plated surface |
| Total Surfaces: | 1 (RS03), 2 (RS04) |
| Tracks per Surface: | 64 |
| Sectors per Track: | 64 |
| Words per Sector: | 128 bytes (RS03), 256 bytes (RS04) |
| Density: | xxx bpi (maximum) |
| Recording Method: | MFM |
| Physical Size: | 15-3/4" (high), 19" (width) |
| Weight: | xxx lbs |
| Power Consumption: | 13A (starting), 4A (operating) |
The RS03 and RS04 disk drives were MASSBUS fixed-platter fixed-head disk drives. Their basic format was 18-bit words (for use in PDP-10 and PDP-15 machines), but they couldbe used in PDP-11s, where they simply ignored two bits.
The RS04 doubled the capacity (and bit rate) of the RS03 by recording on both sides of the platter; alternate bits in each word came from alternate sides.
They could store up to 512KB of data in 128 byte blocks (RS03), or 1024KB of data in 256 byte blocks (RS04). They used xx fixed read/write heads for data, and yy heads to read timing/address tracks (in two duplicated sets of 3, for reliability; switch-over from one set to another was manual).
