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Re: OS2200 MFD question

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On 2025-01-12 1:49 p.m., lewiscole wrote:

> Well, I could be wrong, but I suspect that the Exec won't allow a user
> to arbitrarily look at anything on disk using a IOW$ or any other I/O
> related ER.
> 

 From looking at an admittedly old version of MFD, this is exactly how 
it reads the MFD. It uses ER IOW$, reads sector 0 to get the pointer to 
the MFD and starts to read certain parts of the MFD into a temporary file.

> Regardless of the reason, I'm pointing out that you may be violating the
> terms of your licensing agreement which COULD (at the very least) lead
> the Company to not renewing your PS2200 license if they wanted to.
> That may not be a problem for you, but if you're interested in continue
> to play around with it, it's a risk you should be aware of.
> 

I guess that depends on how you define some of the terms. I have not 
reverse engineered anything. I have not decompiled anything. I have not 
disassembled anything.  I have certainly not tried to execute any OS2200 
code outside of PS2200. I wouldn't want to get into a legal argument 
with Unisys so perhaps I will desist from satisfying my curiosity in 
this matter.

>>> Unfortunately, Univac/Sperry Univac/Sperry/Unisys (USUSU) has had a long
>>> standing habit of making such old manuals disappear and so I suspect
>>> that it will be virtually impossible for you to find such a manual.
>>
>> Very true. I have an old version of the Data Structures manual and there
>> is a lot of stuff in there that isn't in the new one. There are problems
>> with even the old manual though. First, it assumes a level of knowledge
>> of Exec internals that I simply don't have. [...]
> 
> The Exec is a proprietary product and I doubt that the Company is going
> to release its source, and the Company clearly doesn't want users to
> find out how things work internally on their own.

I can't argue with that. If I were trying to make an emulator to run 
OS2200 I can see where they would be upset. But that is not my goal and 
like I said I don't need any conflict with Unisys' legal team so ...

> 
> Well, I could be wrong, but I suspect that the Exec's file system isn't
> something that is going to change much without a very good reason.
> 

Some things like using TDATE$ format dates need to change.

> It could be a coincidence, but I can't help but feel that there's a
> possible correlation between your having to subtract 18 (i.e. 2 * 9) in
> order to get your addresses to work out.
> It's just a thought.
> 

I've wondered about the same thing myself but have been unable to come 
up with any logical reason for it.


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OS2200 MFD question Stephen Boyd <sboydlns@gmail.com> - 2025-01-11 09:29 -0500
  Re: OS2200 MFD question l_cole@juno.com (lewiscole) - 2025-01-11 20:06 +0000
    Re: OS2200 MFD question Stephen Boyd <sboydlns@gmail.com> - 2025-01-12 10:22 -0500
      Re: OS2200 MFD question l_cole@juno.com (lewiscole) - 2025-01-12 18:49 +0000
        Re: OS2200 MFD question R Daneel Olivaw <Danny@hyperspace.vogon.gov> - 2025-01-13 08:41 +0100
        Re: OS2200 MFD question Stephen Boyd <sboydlns@gmail.com> - 2025-01-13 10:02 -0500
          Re: OS2200 MFD question l_cole@juno.com (lewiscole) - 2025-01-15 02:04 +0000
            Re: OS2200 MFD question David W Schroth <davidschroth@harrietmanor.com> - 2025-01-31 22:34 -0600
              Re: OS2200 MFD question l_cole@juno.com (lewiscole) - 2025-02-02 20:50 +0000
                Re: OS2200 MFD question David W Schroth <davidschroth@harrietmanor.com> - 2025-02-02 20:23 -0600
          Re: OS2200 MFD question David W Schroth <davidschroth@harrietmanor.com> - 2025-01-31 22:30 -0600
            Re: OS2200 MFD question Stephen Boyd <sboydlns@gmail.com> - 2025-02-01 10:21 -0500

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