> On Feb 9, 2017, at 8:39 PM, Paul Koning <[email protected]> wrote:
>
> Gents,
>
> I'm looking at a set of RSTS V7 magtape images (a release kit) which have an
> odd format that gives SIMH fits.
>
> In the container formats I'm used to, each tape block image is preceded and
> followed by the data length as a 4-byte value. In SIMH that's rounded up to
> even, in E11 format it's not, but apart from that this is how things work.
>
> The V7 tape images don't match that format. It looks like each block
> contains not just the data but also 2 more bytes, and the data length value
> represents that extra 2 bytes. So the tape label is 16 bytes, not 14, and
> the data blocks are 514 bytes, not 512.
>
> Does this ring any bells? Where do those extra bytes come from? Can SIMH be
> told to deal with this or does it require a repair program to fix the format?
I wrote a simple program to strip off those two bytes everywhere, and the
result was a set of V7 kit tapes that work nicely. Trying to remember how to
do a V7 installation with no docs was interesting...
paul
