HP 85 ASCII ART

HP 85 ASCII ART DEMO

Technical Documentation

I needed to create quite a bit of stuff to make this working:

1. HP-85 program to interface with the tape: HP-85 program to read from HP 7970 Tape

2. Hardware for generating HP-IB parity on the fly: FPGA HP-IB Parity Generator

3. ASCII art files: ASCII Art Text Files

4. Program to generate the SIMH tape from ASCII pictures: bin2simh

5. Resulting SIMH tape file: ascii2.tap

6. DOS utility to write to a SCSI 9-track tape (written by John Wilson): DOS "ST" SCSI Tape Drive Utility

7. DOS utility to read from a SCSI 9-track tape (written by Chuck Guzis): DOS "STP2TAP" SCSI Tape Drive Utility

Procedure and software to write the physical tape

Unfortunately you can't write to the HP 7970 tape drive from the HP 85. That's because the 85 cannot keep up with providing data fast enough to the tape, and you'll get a timing error. So instead, the physical magnetic tape used in this demo was written using another SCSI tape drive, my HP 88780B (also known as the HP 7980), as shown in this video (reproduced below).

I used a DOS machine with a SCSI card to connect to the HP 88780, and ran the DOS "ST" utility written by John Wilson . The command to used to write the above SIMH .tap file to the physical tape was (my tape SCSI address was 5):

st -f scsi5: iput ascii2.tap

Similarly, to read the file back, use

sst -f scsi5: iget dump.tap

Or you can use Chuck Guzis' STP2TAP utility above, which can read back, but not write. In this case the command is:

stp2tap dump.tap

Video of the HP 8870 Tape used to write the physical tape for the demo

Video of the repair of the HP 2631G used in this demo

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