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From: mrh@camcon.co.uk (Mark Hughes)
Newsgroups: comp.sys.ibm.pc
Subject: DesqView 386 vs VM/386 comparisson
Message-ID: <3425@titan.camcon.co.uk>
Date: 31 Jul 89 15:49:47 GMT
Organization: Cambridge Consultants Ltd., Cambridge, UK
Lines: 85


This is a summary of replies to the following posting of about ten days ago.
Many thanks to those who replied, in particular to Larry Hastings who
took a lot of trouble to provide a structured critique of both products.

<Please mail me with any comments you have on likes/dislikes/problems of
<
<	Quarterdeck's	DesqView 386
<and	IGC's		VM/386
<
<Comparative information is of particular interest.

I received only four replies, but they have enabled me to decide on DesqView
386 (DV) for my own purposes, although VM/386 (VM) is not to be ruled out. The
replies were:-

	1 from a very pleased VM user with no direct experience of DV.
	1 from an equally pleased DV user with no experience of VM.
	1 from an extremely dissatisfied (ex) DV user.
	1 from LH above with experience of VM in beta test form, and who is
	currently an enthusiastic user of DV.

There was one very positive comment about support from IGC (VM/386) and one
very negative comment about support from Quarterdeck (DesqView 386).

The dissatisfied (ex) DV user had a lot of installation problems, failed to
get DV to work with his Logitech hi-res bus mouse, and got no help from
Quarterdeck.

Remember that this is only a summary. If you are seriously trying to decide
between these products maybe you ought to read the postings in full.  Send me
your email address if you want a copy.

Differences between DesqView 386 and VM/386
-------------------------------------------
DesqView 386 is really just ordinary DV with an extra program, QEMM, which
allows DV to treat exTENded memory as exPANded memory. (DV only understands the
latter.) As such DV swaps programs between the DOS RAM partition and higher
memory, rather than creating virtual machines. VM understands 386 exTENded
memory and makes use of it to create virtual machine's. Hence these two
programs use fundamentally different approaches to achieve the same basic
end: Multiple copies of DOS and DOS based programs running concurrently on
a single PC (single user).

DV's approach has the disadvantage of using more memory than VM, (amount
disputed: 50k to 114k) but has the advantage that all hardware devices are
available to all DV tasks. VM will use less memory, but with some exceptions
(keyboard, screen, disk drives and possibly printer) hardware devices
are available to only one virtual machine at a time. Hardware devices such
as COM1 (etc) are allocated to a specific virtual machine at start up, and
must be manually re-allocated if you want access to them from a (program
running on a) different virtual machine.

Apparently the beta test version of VM had an "abominable disk-access overhead"
compared to DV. This may well have been improved.

DV allows tasks to "co-exist" within windows on a single screen, or to have
their own full screen. VM provides only the latter.

DV allows you to control how much processor time (how many slices per second)
is allocated to the foreground task and how much to any background tasks. VM
allows greater control enabling you to control the fineness of the time
slicing and to adjust how many slices each program receives per second
individually.

Summary ends.

I cannot vouch for the accuracy of any information in this posting and
report it with minimal interpretation in good faith. If any feature
mentioned is important to your purchase decision, check it out yourself
directly with the relevant manufacturer.

I'd still be interested to hear comments on the comments by the way, so
if I've made an error or you know something important that I haven't mentioned
let's hear about it - don't mail me this time though, please post a follow up.

------------------- <mrh@camcon.co.uk>  or  <...!mcvax!ukc!idec!camcon!mrh>
|   Mark Hughes   | Tel: +44 (0) 223 420024   Cambridge Consultants Ltd. 
|(Compware . CCL) | Tlx: 931 211 0193 (KZ G)  The Science Park, Milton Road,
------------------- BT Gold: 72:MAG70076      Cambridge UK. (Own opinions etc.)
-- 
------------------- <mrh@camcon.co.uk>  or  <...!mcvax!ukc!idec!camcon!mrh>
|   Mark Hughes   | Tel: +44 (0) 223 420024   Cambridge Consultants Ltd. 
|(Compware . CCL) | Tlx: 931 211 0193 (KZ G)  The Science Park, Milton Road,
------------------- BT Gold: 72:MAG70076      Cambridge UK. (Own opinions etc.)