[Simh] Tape conversion issues

[Timothe Litt]

On 03-May-15 12:42, Cory Smelosky wrote:
>
> An SC-40 with a DLT-7000 tape drive hanging off it, using a (Probably
> heavily modified) TOPS-10.
>
Ah. Non-DEC hardware all around.
>
> Hmmmm.  I wonder why the SC-40 running this TOPS-10 build is using
> high-density mode then?
>
Probably because the SC hardware and TOPS-10 patches added support for
it.  It does pack data more densely.
(2 words in 9 frames rather than 1 word in 5.)

> I've heard that there's some sort of command to change the tape
> format, any ideas?
>
On a modified OS on non-DEC hardware?  No.
> If I have time later today, I'll write a conversion utility to convert a
>> tape image from high-density to core dump mode.  I suspect this will
>> solve your problem - but in any case, it should be generally useful.
>>
>
> Thanks, yes - that should help.
>
Pre-release on github, just for you.  I just posted an announcement.
>> Can you provide a (preferably small) sample tape so that I can verify
>> this analysis?
>>
>
> Sadly, it's >300M (explains the high-density mode, now that I think
> about it) and I must control its spread so I'll send it to you off-list.
>
I don't accept mail bombs.  If you e-mail something that large, it will
be rejected by my mailer.

You can test the conversion, or just do a backup of a small file (say,
10 blocks).  That's all that's required to know if it works.

If necessary, I can provide a dropbox on my server, but I don't think
it's necessary.   The math says it's probably high-density.

It's possible that SC implemented a DIFFERENT high-density mode; in that
case if you can scare up documentation on what they did, it's pretty
easy to add a mode to tape36 (the converter.)




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