Filter
Top Products
A-13
A
Before formatting a Winchester disk, the MVME147 SCSI firmware sends a
mode select command for drive geometry parameters (page 4) to the
controller. Below is the command descriptor block for the mode select
command:
Mode Select Command CDB
4. Alternate tracks per volume is taken from the attach
packets alternate cylinders to reserve field (byte offset $1F
for "old" attach ($08), or offset $29 for "new" ATTACH
($78)) multiplied by the number of heads (to convert to
tracks).
5. The number of sectors per track, logical sectors per track,
the attach packet (byte offset $0C) plus spare sectors per
zone (byte offset $1E) if zone = track bit 11 byte offset $10 =
1
6. Bytes per sector is taken from the attach packet byte offset
$1C.
7. Interleave is taken from the format packet byte offset $0E.
8. Track skew factor field is left as the default value as
returned from the mode sense command.
9. Cylinder skew factor field is left as the default value as
returned from the mode sense command.
10. Drive type field bits HSEC bit are set if the hard-sectored
media (bit 8) is set in the attach packet attribute word byte
offset $10. Otherwise, the SSEC bit is set. Other bits in this
field are set to 0.
11. This field is left as the default value as returned from the
mode sense command.
BYTE OFFSET
VALUE COMMENTS
0 15 Command code
1 10 LUN = 0, PF = 1, SP = 0
200Reserved
300Reserved
4 (Note) Parameter list length
5 00 Control byte: no link, no flag