76
The Disc Interface state contains these registers:
Name
Size
Radix
Description
CWR
16
8
Control word register
SWR
16
8
Status word register
IDR
16
8
Input data register
FCNT
5
10
FIFO fill count
FIFO [0:15]
20
8
Data FIFO
ACPT
4
2
Bus acceptor units bitmap
LSTN
4
2
Bus listener units bitmap
TALK
4
2
Bus talker unit bitmap
PPR
8
2
Parallel poll response bitmap
BUSCTL
8
2
HP-IB control lines
CTL
1
2
Interface control
FLG
1
2
Interface flag
FBF
1
2
Interface flag buffer
SRQ
1
2
Interface DCPC service request
EDT
1
2
End of data transfer flag
EOR
1
2
End of record flag
BUFFER [0:137]
16
8
Sector buffer
DSJ [0:3]
2
10
Controller Device-Specified Jump, drives 0-3
ISTATE [0:3]
4
10
Interface state, drives 0-3
ICMD [0:3]
4
10
Interface command, drives 0-3
5.5 13175D Disc Controller Interface with Eight 7905/7906/7920/7925 Drives
The HP 13175D Disc Controller Interface connects 7905A (15 MB), 7906A (20 MB), 7920A (50 MB), and 7925A
(120 MB) disc drives to the HP 1000. The subsystem consists of the interface, a 13037D Multiple Access
Controller (MAC), and from one to eight MAC drives. The subsystem uses DCPC to achieve a 937.5 KB/second
transfer rate to the CPU.
The disc controller connects from one to eight disc drives to interfaces installed in from one to eight CPUs. The
drives use a common command set and present data to the controller synchronously at a 468.75 kiloword per
second (2.133 microseconds per word) data rate.
The disc interface is used to connect the HP 1000 CPU to the 13037’s device controller. While the controller
supports multiple-CPU systems in hardware, the simulator does not provide this capability.
Attaching a disc image file to a unit simulates inserting a disc pack into a drive:
ATTACH {-R} DSn <image-filename>
Adding the
–R
(read-only) switch is equivalent to setting the drive’s Disc Protect or Read Only switch to the
On
position.
If the host operating system returns an error when seeking, reading, or writing a disc image file, the simulator will
report the error to the simulation console, e.g.:
HP 2100 simulator disc library I/O error: No space left on device