Re: how did Microsoft break away from OS/2?

MMI <mmi@xxxxxxxxxxxxx> wrote:

Leauki wrote:
"How come? "Subsystem in NT sense" is basically nothing else than API
router between application interface and kernel interface/drivers. From
this point of view, OS/2 VDM is also a subsystem, since it routes
MS-DOS
calls into OS/2 calls. The only difference is that in NT, no
application, even Win32, at least well-behaved, sees the kernel
interface, whereas in OS/2, native OS/2 applications see the kernel
interface. But DOS or Win16 application pretty much work in a
"subsystem
in the NT sense". "


"From this point of view" should include the "only difference" you
list. Taking into account the difference, "from this point of view",
OS/2 VDM is NOT a subsystem (and neither is NT's DOS emulator). Whether
applications can see the kernel interface or not is a major difference.

Well, but then DOS application can't see OS/2 kernel interface, can it?

No. But they run in a VM.

NT's native API is undocumented and not used, except by subsystems. All
applications use one the subsystems (Win32, OS/2, or Interix in Windows
2000). None of the applications have direct access to the kernel. That
makes Windows NT less compatible but it adds stability.

Windows-in-Windows and the rest of the DOS emulator are part of the
Win32 subsystem.

I got confused a bit here - sometimes, even the MS materials refer to
this thing called "NTVDM" as "MS-DOS subsystem" - I thought it was done
the similar way to other subsystems - however I found a bit of
information somewhere at Microsoft that described NTVDM as Win32
application. I stand corrected.

NTVDM (and WoW) is a part of the Win32 subsystem. The Win32 subsystem is
indeed a little all-powerful, or so it seems. In reality Win32 has two
special things going for it.

It is the only mandatory subsystem (meaning that you can use NT without
he other API subsystems but not without the Win32 subsystem) and it is
the only subsystem that has access to the screen (meaning that the other
subsystems must use Win32-provided VIO/terminal windows or a Win32-based
X server.

A common solution to the first problem is to ignore it (since enough
operating systems without Win32 exist). The second problem is usually
solved by installing Cygwin and a Cygwin-compatible X server
(essentially a Win32 X server).




--
Andrew J. Brehm
Marx Brothers Fan
PowerPC/Macintosh User
Supporter of Chicken Sandwiches
.

Relevant Pages

  • Re: how did Microsoft break away from OS/2?
    ... "Subsystem in NT sense" is basically nothing else than API ... router between application interface and kernel interface/drivers. ... calls into OS/2 calls. ...
    (comp.os.os2.advocacy)
  • Re: how did Microsoft break away from OS/2?
    ... router between application interface and kernel interface/drivers. ... this point of view, OS/2 VDM is also a subsystem, since it routes ... calls into OS/2 calls. ...
    (comp.os.os2.advocacy)
  • Re: how did Microsoft break away from OS/2?
    ... subsystem was removed in Windows XP. ... OS/2 has nothing like that. ... NT is what NT used to also run DOS programs. ...
    (comp.os.os2.advocacy)
  • Re: OS/2 subsystem in Windows NT
    ... I think Apple's Yellow Box was implemented as a subsystem. ... But then, hey, I don't want to solve all the daily Windows issues to run OS/2 apps. ... that OS/2 subsystem is Microsoft - having exclusive access to NT codebase and 16bit OS/2 codebase. ...
    (comp.os.os2.advocacy)
  • Re: Confused about which way to go
    ... First versions of NT was supposed to run OS/2, posix and Win32 ... Every subsystem eventualy called native NT API. ... posix and OS/2 subsystems become absolete. ...
    (borland.public.delphi.non-technical)