Xenix running DOS applications on 80286

[John Gayman]

In article <4718 at xenna.Encore.COM>, paradis at pinocchio.encore.com (Jim Paradis) writes:
> I own an 80286-based PeeCee clone, and I would like to put up a
> version of Un*x on it that will also run DOS applications.  Most
> 
> 	(1) Anybody have any experiences with Microport Xenix
> 	and/or Dos Merge on the 286?

    First off, Microport's product is Unix, not Xenix. :-)  Thier port
  is System V, release 2 on the 286. The DosMerge does basically work
  but it suffers from some restrictions. If your DOS tasks are going
  to involve heavy serial I/O, then you might have problems. What the
  provide you is a virtual console for DOS. At the command line you can
  type "dos" and you'll get the prompt. It will *not* multitask DOS.
  When in DOS, your Unix applications continue to run. When you exit DOS,
  your DOS task will suspend itself. This is the first major difference
  in the 386 Merge stuff. It can run multiple DOS sessions and they run
  concurrently with Unix. For Merge, plan to have a *minimum* of 1.5MB
  of RAM with ~3MB being recommended.

> While I'm at it, here's another question:  I notice that Microport
> offers both two-user and unlimited-user versions of their systems,
> with significant price differences between the two... could someone
> tell me how they enforce the two-user limit?

    The kernel only allows two logins. So if you have two people logged
in and a third tries, he/she will get a "system busy, try later" or 
something to that effect. These limitations are hard-coded into the 
kernel.

> Finally, does anybody know of a mail-order house that sells Microport
> products cheap?  To paraphrase the Speedy Muffler commercial, "I'm NOT
> going to pay a LOT for this kernel!!!" 8-)

    I seem to recall a place called Programmers Connection that advertises
in Byte magazine. Thier prices looked slightly lower than getting it
directly from uport.


						John



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