OS/2 vs DOS/Windows vs Linux re: Interrupts

OS/2 vs DOS/Windows vs Linux re: Interrupts

Post by Simon Galt » Fri, 17 Feb 1995 10:28:00



Very quick question:

A lot of people have told me how much better interrupt handling is in
Linux over OS/2 or DOS/Windows.  As I have not yet made up my mind as to
which OS to stick with, I'm hoping that someone can enlighten me here!

                                Thanks,
                                        Simon
--
||| | || || *New* Generic Sig                            \|/ ____ \|/

||| | || ||                                              /_( \__/ )_\

|| 01416 || Information Technology Dept, Sheridan College, Oakville, ON, Canada

 
 
 

OS/2 vs DOS/Windows vs Linux re: Interrupts

Post by forsy.. » Fri, 17 Feb 1995 15:55:01



>A lot of people have told me how much better interrupt handling is in
>Linux over OS/2 or DOS/Windows.

What do you mean "interrupt handling"?

Depending on what you mean, DOS could actually be "better".

---------------------------------------------------------------------------


 
 
 

OS/2 vs DOS/Windows vs Linux re: Interrupts

Post by Doug DeJul » Mon, 20 Feb 1995 06:09:33




>Very quick question:

>A lot of people have told me how much better interrupt handling is in
>Linux over OS/2 or DOS/Windows.  As I have not yet made up my mind as to
>which OS to stick with, I'm hoping that someone can enlighten me here!

Well, DOS spends a lot of its time in real mode, and thus uses the
real mode interrupt dispatch mechanism and real mode interrupt
handling code.  Linux is a full 32-bit OS, and so will use the
capabilities of the 386 to its fullest, even when servicing hardware
interrupts.

Does anyone know what Windows-95 is going to do in this regard?  My
suspicion is that they're going to use 16-bit real-mode ISRs, and the
protected mode ISRs (for when Windows is in protected mode) will
switch to real mode and call the real mode ISR.  I also assume OS/2
does this correctly (ie. has full protected mode ISRs for hardware
interrupts).
--



 
 
 

OS/2 vs DOS/Windows vs Linux re: Interrupts

Post by Larry Hastin » Mon, 20 Feb 1995 18:01:00



>Does anyone know what Windows-95 is going to do in this regard?  My
>suspicion is that they're going to use 16-bit real-mode ISRs, and the
>protected mode ISRs (for when Windows is in protected mode) will
>switch to real mode and call the real mode ISR.  I also assume OS/2
>does this correctly (ie. has full protected mode ISRs for hardware
>interrupts).

Actually, you have it exactly backwards WRT Windows 95.  The ISRs are
uniformly written in protected mode (with the exception of a dozen or
so MS-DOS function calls off of INT21), and when 16-bit programs call
them, they get trapped and thrown upstairs into 32-bit-land.  In fact,
I think the holy trinity of Windows 95, OS/2 Warp, and Windows NT all
handle interrupts in this way (although the latter two don't bother
with the legacy code).

In fact, it's this wunderbar replacement of MS-DOS services that makes
Windows 95 so much nicer than Windows 3.1.  You can format a floppy
in the background without degrading your background modem download or
making your foreground interactive window sluggish.  The file I/O is
all 32-bit local-blocking I/O, the serial port is handled with a
streamlined 32-bit driver; it's all sleek 32-bit code now, and the
system has finally achieved a certain peppy synergy.

I know, I know, people have been doing this for years with their
UNIX / NextStep / Amiga / OS/2 / * chew toy, but for millions
of Windows 3.1 users upgrading directly to Windows 95 it'll be
welcome relief.

--

"MELROSE!  I'm SORRY!"
<a href="http://www.veryComputer.com/~funkster">My WWW homepage</a>

 
 
 

OS/2 vs DOS/Windows vs Linux re: Interrupts

Post by Doug DeJul » Thu, 23 Feb 1995 08:51:02


Quote:>Actually, you have it exactly backwards WRT Windows 95.  The ISRs are
>uniformly written in protected mode (with the exception of a dozen or
>so MS-DOS function calls off of INT21), and when 16-bit programs call
>them, they get trapped and thrown upstairs into 32-bit-land.

YAY!  Microsoft does something right.  I can't wait to get my hands on
this.  When does the open beta program start?

(And no, I wouldn't be satisfied with OS/2 or Windows-NT -- I've got
Linux as a 32-bit OS; I need something better for running DOS games,
not software I actually do *work* on, and it's gotta be compatible
with MS-DOS all the way down to the side effects of bugs.  When I
heard that the sound on the DOS version of DOOM didn't work 100%
correctly under OS/2, I lost all interest in OS/2 forevermore.)
--