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HPCONVERT(1) General Commands Manual HPCONVERT(1)


hpconvert - convert HP disk image between SIMH and HPDrive formats


hpconvert FILE


HPDrive is a free program written by Ansgar Kueckes that uses a PC and a GPIB card to emulate a variety of vintage Hewlett-Packard disc and tape drives that interface to computers via the HP-IB.

hpconvert converts an HP disc image from SIMH to HPDrive format or vice-versa. This permits interchanging images between the two programs.

SIMH writes and reads disc images in little-endian format, regardless of the byte order of the host. In addition, SIMH accesses images for the the 7905 and 7906 drives in platter order (i.e., all tracks on heads 0 and 1, followed by all tracks on heads 2 and 3) to improve locality of access. It accesses images for the 7920, 7925, and all CS/80 drives in cylinder order.

HPDrive writes and reads images in big-endian format, regardless of the byte order of the host, and accesses all images in cylinder order.

This program swaps each pair of bytes in the disc image. In addition, if the image is precisely the size of a 7905 or 7906 drive (15,151,104 or 20,201,472 bytes, respectively), the access order is restructured from platter to cylinder, or vice-versa.

Note that SIMH does not currently create full-size disc images unless the last sector on the drive is written. Therefore, it is recommended that new images be initialized using the RTE FORMT or SWTCH programs to ensure that the image files are of the correct size for this program and HPDrive.

This program creates a scratch file to store the converted image. Only when conversion is complete is the original file deleted and the scratch file renamed to the original file's name. Running the program twice on the same file will return the file to its original configuration.

To decide the mode used in a 7905 or 7906 image, the program examines the OS signature at the start of the file and compares it against a list of known operating systems. If the OS signature is not recognized, the program terminates without altering the file. Signature checking is not performed on images other than those for the 7905 and 7906; those images are byte-swapped unconditionally.

Signatures for these operating systems and compatible 7905/06 drives are recognized:

HP 1000 RTE-IVB: 7906H ICD
HP 1000 RTE-6/VM: 7906H ICD
HP 3000 MPE: 7905A/7906A MAC

The signatures are contained in the first four words at the start of each disc image. In hex representation, they are:

MPE MAC: 5359 5354 454D 2044 ("SYSTEM D")

These represent the start of the boot extension for RTE and the start of the system disc label for MPE. The boot extension machine instructions are:


62000         LDA   EQU 062000B
72000         STA   EQU 072000B
01200         O0    EQU HSTRT-1400B
02600 063555  HSTRT ABS LDA+HHIGH-O0   (word 1)
02601 003300            CMA,CCE        (word 2)
02602 073553        ABS STA+HRCNT-O0   (word 3)
02603 005500            ERB            (word 4)
02753 000000  HRCNT NOP
02755 077377  NW#DS OCT 77377
02755         HHIGH EQU NW#DS


      062000  LDA   EQU 062000B
      072000  STA   EQU 072000B
      000000R O0    EQU HSTRT-1400B
01400 063555  HSTRT ABS LDA+HHIGH-O0   (word 1)
01401 003300            CMA,CCE        (word 2)
01402 073553        ABS STA+HRCNT-O0   (word 3)
01403 005500            ERB            (word 4)
01553 000000  HRCNT NOP
01555 077377  NW#DS OCT 77377
      001555R HHIGH EQU NW#DS

And the disc label is:

MPE MAC and CS/80

00000 051531  LABEL ASC 6,SYSTEM DISC  (word 1)
00001 051524                           (word 2)
00002 042515                           (word 3)
00003 020104                           (word 4)
00004 044523
00005 041440

2017-10-15 simtools