[Simh] Fwd: Making tape/disk images

[Michael Richter]

Oops.  Sent this to Tim only instead of list.

---------- Forwarded message ----------
From: Michael Richter <ttmrichter at gmail.com>
Date: 5 May 2010 21:45
Subject: Re: [Simh] Making tape/disk images
To: "Shoppa, Tim" <tshoppa at wmata.com>


On 5 May 2010 20:59, Shoppa, Tim <tshoppa at wmata.com> wrote:

> Al writes:
> > On 5/3/10 12:30 PM, Tim Newsham wrote:
> >> the code that reads tape images in simh can also
> >> read from a directory instead of a tape image.
> >
>
> >and create what type of on-tape directory structure?
>
> >tape image code knows of nothing above tape blocks and
> >file marks.
>
> Al hits the issue exactly on the head.
>
> If SIMH only had to emulate one operating system, with one OS/application
> tape format, then I think the concept of a "virtual filesystem tape image"
> would be OK.
>
> But SIMH is used with dozens of OS's, with hundreds of different tape
> formats. Seems like things spin out of control to support them all inside
> SIMH.
>
> Now, tools that can manipulate files and load them into tape and disk
> images in OS-specific formats, or go the other way and extract files from
> tape and disk images, has a long tradition. Going back to at least the
> 1970's. My gut feeling is to extend this tradition, not abandon it.
>

Would it not be possible to make a general-purpose tape archive system that
has mid-end plugins for the OS-specific formats and back-end plug-ins for
the simulated physical formats?  This way a single tool with a single
command line could be made that allows things like (example command lines
only):

   - simtar --create --file=myfile.tap --file-system=RSTS9
   --tape-format=SIMH ./*
   - simtar --extract --file=myfile.tcp --file-system=VMS --tape-format=TPC

Unless someone can see any reason why this is intrinsically impossible, I
wouldn't mind taking a crack at such a program written in some scripting
language for proof of concept (and maybe even final form -- I don't see any
particular advantage to writing something like this in C since performance
won't be a huge issue).  Since I'm screwing around with RSTS right now my
first version would be for RSTS, naturally.  I could then pop the code up
somewhere for others to hack onto for other formats.  As new emulators get
attached, new operating systems get resurrected, etc. the program could be
expanded with plug-ins.

-- 
"Perhaps people don't believe this, but throughout all of the discussions of
entering China our focus has really been what's best for the Chinese people.
It's not been about our revenue or profit or whatnot."
--Sergey Brin, demonstrating the emptiness of the "don't be evil" mantra.



-- 
"Perhaps people don't believe this, but throughout all of the discussions of
entering China our focus has really been what's best for the Chinese people.
It's not been about our revenue or profit or whatnot."
--Sergey Brin, demonstrating the emptiness of the "don't be evil" mantra.
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