As I get ready to restart the Sigma project, I've gone back through the
Sigma disk specs. My notes are attached. The current simulation module
is not accurate, most notably in the way it allows controller/disk
pairings that didn't exist in real life.
Comments are welcome.
/Bob
Notes for the Sigma Disk Controllers
Two patterns of disk controllers - "10 byte" sense controllers and "16 byte"
sense controllers
All disks have 1024B (256W) sectors
model units/cylinders/heads/sectors type
7240/7242 8 / 203 (3 spare) / 20 / 6 10 byte
7260/7261 15 / 203 (3 spare) / 20 / 11 16 byte
7265/7266 15 / 411 (7 spare) / 20 / 11 16 byte
7270/7271 8 / 406 (6 spare) / 20 / 6 10 byte
7275/7276 15 / 411 (7 spare) / 19 / 11 16 byte
T3281/T3282 15 / 815 / 19 / 11 16 byte
T3281/T3283 15 / 815 / 19 / 17 16 byte
T3281/T3286 15 / 555 / 30 / 17 (16?) 16 byte
T3281/T3286F 15 / 555 / 60 / 17 (16?) 16 byte
T3281/T3288 15 / 822 / 5 / 17 16 byte
header format 7240 726X/727X/T3281
bytes 0-3 flaw / 0 / C / H flaw / 0'CH / C / H
bytes 4-7 S / alt C / alt H / 0 S / alt CH / alt CL'alt
H / 0
sense status 7240/7270
bytes 0-3 0'CH / C / H / S most recent address
bytes 4-7 M'CS / diag / diag / diag seek intr + current
sector
bytes 8-11 stat / stat
726X/7275
bytes 0-3 W'0'CH / C / H / S W = write protect, most
recent address
bytes 4-7 M'R'CS / cnf / stat / 0 M = modifier, R =
reserve/release mode
bytes 8-11 stat / stat / modi / fiers
bytes 12-15 check / bytes / 0'dh / dl 14-15 = difference
sense byte 5-6
7240,7270
0-15 header parity check bytes
726X, 7275, T3281
0 1 for dual access
1-3 device type
5 = 7261
6 = 7266
7 = 7276, T3286
4-7 device physical addr (cable position)
0 device fault
1 write fault
2 loss of on cylinder
3 offset polarity
4 airflow loss
5 parity error on device ID byte
6 spindle speed fault
7 positioning servo faulT
sense byte 7
7240, 7270 726X, 7275 T3281
0-7 LSB of difference 0 physical address
(unique)
sense bytes 8-9
7240, 7270 726X, 7275, T3281
0 data parity error check write error
1 check write error data check error
2 sector verif error IOP parity error
3 head verif error data overrun
4 cylinder verif error head addr incr err
5 sec addr !=0 @ hdr wr arm in motion err
6 diff sent to device order parity err
7 sector sel to device test mode err
0 ctrl sel to device seek transfer err
1 head sel to device device unavailable
2 cyl sel sent to device head addr ver err
3 seek forward set sector addr ver err
4 read gate to device cyl addr ver err
5 write/erase to device 726X, 7275: 0
T3281: ctrl overtemp
6 read cyl sel to device channel addr err
7 7240: not used missing on sect
7270: MSB of diff
sense bytes 10+
10-11 modifier bits
12-13 check bytes
14 0'diff high
15 diff low (absolute value)
operations 7240 726X
7270 7275
T3281
01 write x x
02 read 2 x x
03 seek x x
04 sense x x
05 check-write x x
07 reserve x
09 header write x x
0A header read x x
0F condition rls intr x
12 read 1 x x
13 select test mode x x
17 release x
1F condition rls intr x
23 release x
33 restore x x
83 seek with interrupt x x
B3 restore with interrupt x
TIO, SIO, HIO status
all
0 interrupt pending
1-2 device state
00 = ready
01 = not operational
10 = reserved
11 = busy
3 1 (automatic)
4 unusual end
5-6 controller state
00 = ready
01,10 = n/a
11 = busy
7 0
TDV status
7240, 7270 726X,7275 T3281
0 data overrun 0 error corrected
1 flaw mark flaw mark flaw mark
2 sector unavailable programming err programming err
3 0 write prot err write prot err
4 header verif error IOP parity err IOP parity err
5 on cylinder operational err operational err
6 seek timeout error verification err verification err
7 header parity error header parity err header parity err
AIO status
7240, 7270 726X, 7275, T3281
0 data overrun data overrun
1 0 attn int ack
2 0 rls int ack
3 0 0
4 on sector interrupt on sector intr
5 on cylinder 0
6 seek timeout error seek timeout error
7 0 0
operational status byte (SIO, HIO, TIO, TDV)
all
8 incorrect lnt
9 xmit data error
10 xmit memory err
11 mem addr err
12 IOP memory err
13 IOP ctrl err
14 IOP halt
15 0
operational status byte (AIO)
all
8 incorrect lnt
9 xmit data error
10 zero byte cnt intr
11 channel end intr
12 unusual end intr
13-15 0
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