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5 Programmed Disc I/O Device Simulations
The simulator provides these disc interfaces and their associated peripherals:
•
12557A Cartridge Disc Interface
•
13210A Disc Drive Interface
•
12565A Disc Interface
•
12606B Disc Memory Interface
•
12610B Drum Memory Interface
•
12821A Disc Interface
•
13175D Disc Controller Interface
5.1 12557A Cartridge Disc Interface with Four 2870 Drives,
13210A Disc Drive Interface with Four 7900 Drives
The 12557A Cartridge Disc Interface connects from one to four HP 2870A (2.5 MB) disc drives to the HP computer
family. The 13210A Disc Drive Interface connects from one to four HP 7900A (5.0 MB) disc drives. Both interfaces
consist of two Printed Circuit Assemblies installed in adjacent I/O slots. The Data PCA is assigned the higher-
priority (lower numbered) select code, and the Control PCA is assigned the lower-priority select code. The DPD
and DPC devices simulate these PCAs.
Attaching a disc image file to a unit simulates inserting a disc pack into a drive:
ATTACH {-R} DPCn <image-filename>
Adding the
–R
(read-only) switch is equivalent to setting the drive’s Upper and Lower Data Protect switches to the
On
position.
If the host operating system returns an error when reading or writing a disc image file, the simulator will report the
error to the simulation console, e.g.:
HP 2100 simulator DP disc I/O error: No space left on device
...and the simulation will stop with an
I/O Error
message. No error recovery is attempted.
A drive’s unit number is not set explicitly. Instead, the drive unit number is derived from the simulation unit number.
For example, unit DPC0 responds to drive select number 0. Changing the drive select jumpers on a mounted drive
is simulated by detaching and reattaching the disc image file to the corresponding simulation unit.
Device and unit options include configuring the interface and drive type, protection and format status, and the ability
to set drives ready or not-ready. The command forms are:
SET DPC <device-option>
SET DPCn <unit-option>
