These ROM images in Intel binary format are from an early 7081 (Serial Number 180) with 2564 ROMS.

The ROMS had been updated during the instruments life, and are the largest ROM image set I have seen
for these meters.   In IC412 (the highest addressed ROM) the bulk of the content stops at 0FB9, there
is then a largeish area of all x'FF' with more code/data starting at 1C00, and ending at 1EAD, and
finally starting at 1FD8, there is the string:

"VDD BSW  8 De 86  8 50"

followed by some more binary data to the high 1FFF address. The string looks awfully like a compile
date and time.   All the other ROM sets I have seen for the earthy processer have '84 dates.

The CRC16 checksums are:
 
 IC430	3238
 IC415	C5C0
 IC414	1260 
 IC413	B958
 IC412	ED50

The ROM on my floating logic board is also a 2564 and has also been updated.

The CRC16 checksum is:

 IC803	8900

Most of the data in this ROM stops at 11ED, except that at the end, starting at 1FDA, is the string:

"VAF BSW 13 Fe 84 11 07"

followed by some more binary data to the high 1FFF address.

The dates and content of the ROM images from two other 7081s fitted with 2764s for this ROM appear
to be the same, though the string reads: "VBA BSW 13 Fe 84 11 07".

Apart from that the only difference is in the first byte of the ROM image:

Comparing IC803.bin and 7081-51.BIN...
Compare error at OFFSET 0
file1 = 174
file2 = 178
Compare error at OFFSET 1FDB
file1 = 65
file2 = 66
Compare error at OFFSET 1FDC
file1 = 70
file2 = 65
Compare more files (Y/N) ? n

Likely the first byte is an 8-bit value to make the 8-bit additive checksum come out with a value of
zero, as the difference in value of four matches up with the differences in the other two bytes that
differ.


Dave Partridge
david.partridge@dsl.pipex.com