Eric said:
>I assume that Desqview is also closely linked to some
>high end version of EMM386, probably QEMM386. Both the
>QEMM386 and Desqview were quite complex - and non-free.
 AFAIK, Desqview would run even in a 8088. It did 
swap processes and their contexts into and out from 
DOS (low) memory at intervals, probably by trapping 
the timer interrupt.
 Of course, if such 8088 did not have EMS hardware, 
swapping would be to disk, hence very slow.
 It also had to trap INT 13, INT 10 and perhaps more,
to make sure a process would not write screen nor 
disk spaces belonging to others.
 
>Drivers and compatibility would indeed be a problem with
>a multitasking DOS, but on the other hand, you can still
>let a single tasking kernel with single tasking drivers
>serve multiple tasks, as long as you have a wrapper which
>makes sure that all kernel calls arrive nicely one after
>another. 
 Extended DOS apps, which need PM and apps which directly 
access hardware were also problems, and interprocess
communication an even worse one. As Eric said, DV was 
quite complex, but, even so, it used only 200kB (not MB)
of RAM.

> I think some old SuSE Linux versions, 5.x or 6.x, came
> with some X server for DOS.
 There is a shareware port of X for DOS, XAPPEAL, which 
can be found at Simtelnet under the heading
../pub/simtelnet/msdos/xwindows/
 The company which made it is long since dead, but its
author is not. 
 I was not able to run it in my 486 computer but I am not 
a programmer nor wanted to spend a lot of time to find out 
what was wrong.

Regards
 JAS


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