TU58 dump tool on Linux?

[Eric Smith]

On Wed, Jun 10, 2020 at 3:30 PM John Forecast via cctalk <
cctalk at classiccmp.org> wrote:

> You could try my “fsio” utility  from the SIMH simtools repository:
>         <https://github.com/simh/simtools/converters/fsio>

I originally wrote it to read/write SIMH disk images in various formats
> (including RT11). I’ve
> never tried it with a tape drive but if it looks like a block device it
> should work.
>

I get a 404 when I click on that link. I think you may have meant:
    https://github.com/simh/simtools/tree/master/converters/fsio
That looks like it would be useful to me for a lot of other things, but
probably not for reading from actual TU58 drives.

A real TU58 drive hooked up to a system running Linux does not look
anything like a block device. Linux has no idea what it is; it's just
something hooked up to a serial port. To read tape blocks, it would be up
to a user space program to send the TU58 the right MRSP commands and
interpret the responses.

There are a number of programs that solve the opposite problem, and make a
PC pretend to be a TU58, but those don't help when what you want to do is
talk to an actual TU58. I haven't seen a program for that. Perhaps some
code from the NetBSD kernel could be useful, but I'm guessing that dealing
with that would be more trouble than just writing a new program.

There are some undocumented MRSP commands, but the documented commands
should be sufficient to read a tape.