🚀 go-pugleaf

In article <9348@sbcs.sunysb.edu> altman@sbstaff2.cs.sunysb.edu (Jeff Altman) writes:
>In article <21454@boulder.Colorado.EDU> wallwey@snoopy.Colorado.EDU (WALLWEY DEAN WILLIAM) writes:
>>Another big question---When Win3.0 goes into protected mode, does it
>>stay there? I'm not talking about the 386 mode or the real mode, but the
>>inbetween mode. It this why you cannot even run behaved programs-like
>>command.com-in a window in the protoected mode.  
>
>I am not sure.  I think so.  But I have yet to read any documentation
>on the Memory handling of Standard Mode.

Standard mode will traverse (reflect) between real and protect mode in order
to use any DOS or BIOS services.  OS/2 can stay in protect mode on a 286
only because all of the services provided by the BIOS and DOS are contained
in device drivers and the like which are written expressly for protect mode 
operation.

Windows 286 protect mode switches modes quite often for interrupts including
timer and hardisk.  If you notice you aren't running as fast as a friends
286 then you probably have an older model 286 machine which doesn't provide
a quick mechanism for switching between modes.

Newer model PS/2's switch VERY quickly compared to an original AT.

Any 386 machine will usually run standard mode much faster than a 286 because
of the processors ability to switch modes itself in software and the
fact that some device driver (video, etc) code will use 386 code
if you have a 386 processor.

----
Glenn Steffler			gpsteffler@sunee.uwaterloo.edu
<Commodore Amiga 3000 - Amiga DOS 2.0 - multimedia defined>