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the algorithm, sketched for review. Nitpicks ? (Miscellaneous)

posted by cm(R) Homepage E-mail, Düsseldorf, Germany, 17.12.2009, 16:19

> being programmers, our first step has to be step zero, right ?

If you get your interface right you can translate between user numbers and developer numbers at one point :-P

> [...] this step is to please CM [...]
> Use Int 2F/1000. -> AX=0 or 1, OK for us to continue; else bail out.

A. The Int2F installation check doesn't return ax, it only returns al.

B. If it returns al = 01h then something strange is going on as well. Better to abort.

C. Int2F.1000 is not reliable. If you really want to please me you have to use a reliable installation check. (Hint: In front of the SDA, and seems NOT to be documented explicitly in RBIL.)

> CS from IOSYS share hooks (0070:0092),

You mean from DATA:0092.

> IF this routine entry is NOT in the HMA, GOTO step 3 below.

Make sure to add the offset*16 and segment for this check. An overflow (CY) means it's in the HMA. As you probably know MS-DOS 7 doesn't use segment FFFFh to address it's DOS code segment in the HMA. (FF39h here.)

> -4. TEST and SET Ninho's bit in the MTI. This establishes the fix proper
> (and could be applied permanently to the IO.SYS file, if desired). If the
> bit was set already, put a message (notice, rather than an error).

This notice might annoy those who patched their kernel file. Might just leave it out, or at least display it on the same line as the program name.

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l

 

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