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Appendix
A
HP 9895A Disc Memory Command Set
Introduction
The following description of the
HP
9895A Flexible Disc Memory command set is HP-IB
rather than CPU oriented. It is given in terms of operations (mainly bytes sent) over the
HP-IB. Since this level is common to any interface to the 9895A, it is machine independent.
A basic knowledge of the HP-IB operation including primary commands, secondary com-
mands, and parallel poll operation is assumed. An
HP
publication "Condensed Description
of the Hewlett-Packard Interface Bus", Part No. 59401-90030, is available for background
information. HP-IB is an implementation of IEEE Standard #488-1978.
Bus Controller
Controller
Unit
Flexible Disc, Disc or Diskette
HP
Format
IBM Format
Physical Track Number
Logical Track Number
Head
Track
Cylinder
Sector
Host System
As used in the manual, is the current HP-IB controller in
charge of the HP-IB.
The 9895A disc controller hardware or firmware.
One of up to four drives connected to the controller.
The coated mylar media used to record data on by the
9895A.
The double-density, single- or double-sided,
HP
standard
recording format.
The single-sided IBM standard recording format.
The track number relative to the outer-most track on the
disc.
The track number recorded on the disc at a physical track.
Logical track numbers mayor may not be the same as the
physical track number.
One of the two sets of read, write and erase elements used
to record data in the unit.
The area defined by a cylinder and head address.
The recording area accessible by the two heads without
moving the head actuator.
The smallest block of data that can be read or written from
the disc.
The system which contains the bus controller.
A-I
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