!Re: Nuke Redmond!

From: allisonp <allisonp_at_world.std.com>
Date: Fri Apr 7 20:04:23 2000

>> the same, with a few notable exceptions where the concept don't match
>> (MS-DOS for example does not have an IOBYTE).
>
>What of those things internal would you have had them leave out in order to
>be more different from CP/M, which was a VERY popular OS at the time,
>without removing its functionality. Since the features to which you refer
>are internal, I assume you have precice citations of common source code,
>right? They're certainly not obvious to me in my role as a fairly frequent
>user.


The features he refers to are the calls to the BDOS to do things like
File_OPEN,
FILE_CLOSE, FILE DELETE..... and so on.

>Since there is only one segment in CP/M, I guess you've got 'em there. Of
>course it really doesn't matter what the location is, does it? I guess any
>OS that load a register and then calls a specific location is a copy of
>CP/M, right?


Not really, CPM loaded to a specific segment but apps could use any and all
to the then 8086 1mb limit.

>> You can also terminate a program by calling location 0000h (again, in a
>> COM program). In CP/M this causes a warm reset (similar functionality).
>>
>It's like saying a FORD is a copy of a Dusenberg because they both use
>wheels.


This was a feature unique to CPM and DOS as many others loc(0) was
either reset (hard), ROM, unused or reserved.

>The mapping of one register set into the other is not an accident. Ask
>Intel about that! I'm told that CP/M-86 is considerably more than a
>translation of CP/M-80. Now you suggest that the roots of MS-DOS are
>entirely in CP/M? They may have common roots, as they reflect the then


CPM-86 was not entirely 8080 code lofted, that would never ru without help.
Also there was a loader change implemented, boot loads a file system aware
loader that finds cpm.sys. This was not the 8080 way.

As far as register usage, that is an artifact of PLM used to write the
V1.3/1.4
and later versions of CPM80. With that convention established it was kept
to keep applications that called the BDOS compatable.

>I've heard that, too. Does that mean that anyone who writes a program to
do
>what he's seen another program do is making a copy? You're not even sure
he
>actually saw and read the source code. How many programmers do you know
>who'd simply copy someone else's work in a case like this? Everybody wants
>to leave his own mark.


DOS 1.0 had COPYRIGHT Digital Research INC inside! There was a quiet
copyright battle that forced DOS 2.0 (buggiest thing in the world!). This
is not
fiction and it was documented.

>Buying something that shortens your burden is kind-of like buying an
>integrated circuit rather than making the thing yourself starting with a
>wheelbarrow of sand. The fact that Microsoft knew that IBM had gone to
>Kildall probably told them what they wanted was sort-f like CP/M.


They didn't care only that there would be apps for it to run like Visicalc!

Allison
Received on Fri Apr 07 2000 - 20:04:23 BST