HP 9836C Technical Computer

A high end workstation computer from HP in the early 1980s primarily for use with CAD and instrument control using the integrated HP-IB (GP-IB/IEEE-488) interface.

Floppy Disk Drives
The internal floppy drives are standard Shugart interface compatible drives, the example I have used Tandon TM200-2A drives, but some units shipped with drives made by Magnetic Peripherals Inc and Control Data as well.

Both of the drives are jumpered at  and   on U1E as described in the Tandon Manual. A Termination pack is also installed by default in U2F.

Double Density 5.25" disks used in the system are formatted with a LIF filesystem using 33 tracks, 16 sectors per track, and 256 bytes per sector for a total capacity of approximately 270KiB. The LIF filesystem measures usage in blocks, these disks have a total block size of 1056.

To decode flux data from a raw image of an internal 5.25" disk, you can use the following diskdef to properly decode it disk hp.lif.40dd     cyls = 33    heads = 2    tracks * ibm.mfm         id = 0         interleave = 1         secs = 16        bps = 256    end end

Note that sector's are 0 indexed requiring id = 0

2023-06

 * Original video cable failed and was replaced with standard male-male DA-15 cable with straight pinout.
 * Computer was originally acquired with a HP 98629A Resource Management Card which was replaced with a HP 98622 GPIO Card since this system will likely never be used with others for the foreseeable future.
 * Floppy drives were disassembled and dry cleaned to remove dust

Archived Media

 * HP BASIC 4.0 on 5.25" Floppy disks

Video Appearances

 * 1981 CAD Monster - HP Series 200 9836C

Related Devices

 * HP 9122C Dual 1.44MB Floppy Drive
 * HP Series 200 Backplane Cards

External Projects and Software

 * : HP Series 200 Emulator
 * : HP-IB external drive host emulation software:
 * : LIF filesystem browser and tools
 * : LIF filesystem browser and tools