IBM CMS dumpfile idiocy

[Chuck Guzis]

On 12/15/2015 07:37 AM, Dave Wade wrote:

> The files are in the same format as on disk. The system just copies
> them back to disk. What size are the blocks as I have a "C" utility
> that will read the older smaller block size files. You can always
> download Hercules and VM/370 ....

Jim, Dave, Peter, Harry et al.:

Thanks for your responses.  The customer says that the tape was made 
during the 1970s on an S/370 system.  He doesn't care about the 
binaries; he'd just like the source code files translated in ASCII. 
That makes the job quite a bit easier.

The general format of the tape looks like this:

34 x 4101 bytes
1 x 2581 bytes
1 x 87 bytes
1 x 177 bytes
1 x 87 bytes
39 x 4101 bytes
1 x 3515 bytes
1 x 87 bytes
39 x 4101 bytes
1 x 3775 bytes
1 x 87 bytes
62 x 4101 bytes
1 x 1013 bytes
1 x 87 bytes
1 x 1125 bytes
1 x 87 bytes
...
(2 x file mark)

The 87 byte records appear to be the metadata; each block has a 
2-character type prefix.  I'll have to sit down and suss the rest out, 
but the 87 byte records appear to contain the file metadata.  The 
content of much of it does appear to be card images--I recognized the 
first logical record as the travel table from the "Adventure" game, so I 
expect that complete source is there.

If anyone gets a lightning strike about this, I can check it out.

Thanks again,
Chuck