ST11950 and ST12550 Installation Guide, Rev. D 15
Characteristics ST12550N/ND ST12550W/WD
Interface Fast SCSI-21Fast & Wide SCSI-21
Multi-seg. cache 1,024 Kbytes 1,024 Kbytes (W)
512 Kbytes (WD)
Capacity
Unformatted 2,572 Mbytes 2,572 Mbytes
Formatted22,139 Mbytes 2,139 Mbytes
Recording
Cylinders (user) 2,707 2,707
Heads 19 19
Avg sectors/track 81 (51h) 81 (51h)
Avg bytes/track 49,768 49,768
Modulation RLL 1,7 code RLL 1,7 code
SCSI rate
Max burst transfer 10 Mbytes/sec 20 Mbytes/sec
Seek time3
Average read 8.0 msec 8.0 msec
Average write 9.0 msec 9.0 msec
Disc rotation
RPM 7,200 7,200
Average latency 4.17 msec 4.17 msec
1Can also be operated according to SCSI-1 protocol.
2Standard factory units are formatted as follows:
512 data bytes per sector, 9 spare sectors per cylinder
1 cylinder at the inner track reserved for spares
3Not including on-board controller overhead.