COMMAND
DESCRIPTION
All
commands executed by the HDC are summarized in the table be-
low. Fields of the command block not specified are don't cares. Fol-
lowing this summary is a generalized description of the commands.
Table 5-6. Command Summary
Command
Class
LUN
LADD
IntJ
Control
Possible
Description
Opcod
Num
(21)
BCNT
Options
Emr
Codes
Read Drive Status
00
0-1 RDS
Restore
to
TKO 01 0-1
06,
RDS
Request Status
03
0-1
Last
Oper.
Check Trk Fmt
05
0-1
L
R
RDE. RDS, IDA
Format Track
06
0-1
L
B
S IDA
Read Drive
08
0-1
L
B
R, S RDE, RDS, IDA
Write Drive
OA
0-1
L
B
R, S 15,
19,
RDS, IDA
Seek
OB
0-1
L
RDS, IDA
Set
Drive Param.
OC
0-1 20,32
Change Command OF 20.32
Block
Address1
Read Drive Long
E5
0-1
L
B
R, S RDE, RDS, IDA
Write Drive Long E6 0-1
L
B
R, S 15,
19,
RDS, IDA
lnit Unit 1 CC
1
20.32
R
=
0
RetnesIECC enable S
=
0
Set
correchon span
to
5
bits
=
1 RetnesIECC disabled
=
1
Set
correchon span
to
1
1
bits
L
=
Logical Sector Address
B
=
Block or sector count required
Read Drive
Status (RDS)
=
02,03,04,20,32
Illegal Disk Access (IDA)
=
20.21.22.32
ReadSedor Error (RDE)
=
11,12,13,14,15
Read Drive Status (Class
Action
0,
Opcode
0)
Read the drive's status and determine if drive is ready. For Hard disk
drives supporting buffered seeks this command
is
useful for deter-
mining the first drive to reach
its
target track. The command will be
aborted, if the drive status read
is
incorrect.
Possible Error Codes
No error, invalid command, seek in progress, drive not ready, write
fault. DMA error.
Restore (Class
0,
Opcode
1)
Action
To Next Page
Loading...
