This (courtesy of google) might give you a starting point.

Perhaps the easiest way would be to 'obtain' a tape (perhaps from whomever you are preparing this for?) formatted to the correct requirements and see if you can read it! Then, if you can, try and emulate it.

From my memory of the late durassic period when I was last involved in playing with IBM standard tape drives, writing a "tape mark" was a single (ioctl?) call to the device. Hopefully your drive has a similar, compatible facility.

<oozing sympathy>Poor Monk</oozing>
Someone has really dropped you in it here haven't they? I hope you didn't smile an nod to this job before it landed on your desk.

Knowing next to nothing about IBM OS, I would suggest you arm yourself with documentation about.

• IBM OS
• the application used to generate the tapes
• the whole EBCDIC ASCII ball of mud

Some things that will trip you up like variable block sizes/record lengths you have already discovered. Getting OT now but your question might have generated more responses if you explained a little more about the environment you are working on the tapes in.

Do you hate Talking to Magnetic Tapes too?

dd does convert asscii to ebcdic but it does NOT write the IBM OS standard label. Also later I need to read EBCDIC tapes created on a IBM mainframe that have variable lenght records. dd seems to completely ignore files on the tape where written like that.


Plankton: 1% Evil, 99% Hot Gas.

Unfortunately, I don't even know what that means :) I just threw it in as a suggestion -- instead of writing a converting module, one can just use dd.