
What was the role of MS-DOS in Windows 95? (2007) - luu
https://blogs.msdn.microsoft.com/oldnewthing/20071224-00/?p=24063
======
userbinator
Much has been written on the system call interface in NT (INT 2E, later
SYSENTER), but there is surprisingly little documented about the 9x system
call interface. So I disassembled its kernel32.dll and looked at where the
function calls went... they all eventually end up at a far call: "call far
[BFFC9734]" with EAX containing what looks like the syscall number, arranged
by major/minor code --- and some of the numbers look suspiciously like the
same as for the original DOS INT21 services.

BFFC9734 seems to be the "magic address" for this.(Googling "BFFC9734" yields
results, but surprisingly, not "BFFC9734h", "0BFFC9734h", or "0xBFFC9734".)

Here are some more references to that I found, if you're curious:

[http://xaknotdie.org/TopDevice/5/articles/z0mb009.htm](http://xaknotdie.org/TopDevice/5/articles/z0mb009.htm)
(Russian)

[http://andrewl.dreamhosters.com/site_z0mbie/ntoskrnl.txt](http://andrewl.dreamhosters.com/site_z0mbie/ntoskrnl.txt)
(English version of above)

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bluedino
It was a bit of a technical achievement that Windows 95 managed to continue
working at all when people buggered it up with 16-bit Windows drivers, DOS
drivers, and old DOS programs like SMARTDRV

~~~
ebbv
It often _wouldn 't_ keep working. Win95/98/Me installs would regularly start
throwing BSOD or just performing terribly and have to be reinstalled from
scratch.

~~~
userbinator
I actually ran a dualboot of 98SE/XP up until around 2004 or so when I
gradually transitioned to XP completely, and 98SE was pretty stable --- as
others have mentioned, it lacks full memory protection so it really depends on
what applications you use; I was never one to install/uninstall lots of apps
"just to try them out", and stuck with old/stable versions of what I needed to
use, so perhaps that has much to do with it.

~~~
krylon
I have a mid-90s ThinkPad with Windows 95 and Office 95 sitting on my shelf. I
cannot do anything with it, because the battery is long gone, it has no
floppy, no CD-ROM, no network. But every once in a while I turn that thing on.
Still runs like a charm, and the performance is good, too, for its age. (It
better be - it's one of those butterfly notebooks, those must have been pretty
expensive way back when...)

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uabstraction
FWIW, I work in a machine shop with many CNC machine HMIs running on Windows
95, 98, NT, and 2000. Somehow, beyond all expectations, they just keep on
working.

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ASipos
If you want a full answer, check out Schulman's Unauthorized Windows 95 and
its sorta-sequel, Pietrek's Windows 95 System Programming Secrets.

It's a sprawling exploration of the insides of this OS with the goal of
answering precisely this question.

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csours
Reinstalling Windows:
[https://www.youtube.com/watch?v=dQuDk3z25Ko](https://www.youtube.com/watch?v=dQuDk3z25Ko)

Sung to the tune of When I'm Cleaning Windows:
[https://www.youtube.com/watch?v=sfmAeijj5cM](https://www.youtube.com/watch?v=sfmAeijj5cM)

~~~
Senji
Did you know you can BSOD Win10 as a host os running VirtualBox when you're
installing Win98se as a guest-os.

During the install(from an iso) it manages to bsod(kernel panic) the host OS
itself.

A workaround for me was copying the files from the iso to a vhd and runing the
setup from a "harddrive" inside the vm instead of emulated cdrom.

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johansch
I kind of dislike the attitude Raymond is showing here, to be honest.

Microsoft did a very poor job of disclosing these very relevant (at the time)
facts to programmers back then. I guess they still hadn't really understood
the power of having a well-documented/readily available platform.

I know that I was hunting for information on this particular topic - just
having gotten dial-up Internet access for the first time in the spring of
1995.

(But hey, there were still a shining light compared to Creative Labs :) )

~~~
hesdeadjim
It had to have been purely defensive to avoid people building even more
assumptions on top of what was already a convoluted mess.

~~~
johansch
Yeah, it's quite easy to imagine that their marketing and PR teams overrode
the technical documentation team on this matter.

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yuhong
When I was discussing the OS/2 2.0 fiasco, I liked to mention how Win9x's
dependence on DOS allowed Caldera to continue to sue MS.

