🚀 go-pugleaf

                         
The following article is from the June 1988 issue of Silicon
Valley Rainbow, the newsletter of the Silicon Valley DEC PC Users
Group.  I thought it so informative as to demand a broader
audience.  It is posted here with the consent of the author and
the editor of the newsletter.
   
Michael E. Macmillan
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A glance inside Rainbow Windows
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By Len Berk
Toronto, Ontario, PC group

     There's good news for Rainbow users: A version of
MS-Windows for the Rainbow exists, and some of us have had
the chance to try it out.

     I've been playing with a copy for about a month, and I'm
happy to report that it does most of what it's supposed to. 
I'll give some details of what it doesn't do shortly.  But
what it does do, above all, is permit a Rainbow to run a
number of current, hitherto unusable, applications.

     MS-Windows is not an application but rather an extension
to DOS.  First conceived at Microsoft early in 1983, it was
designed, in part, to solve the problem of software
incompatibilities among MS-DOS computers, and to provide
multitasking under MS-DOS.

     It does this by providing application programs with all
the hardware interface services they presumably could ever
want and then prohibiting them from laying a finger on the
hardware itself.  The result is that, under Windows,
incompatibility is no more: Any program that runs under
Windows on the IBM PC will run under Windows on the Rainbow.

     Since late 1985, when Windows for the IBM first became
available, perhaps a couple of dozen applications have
appeared commercially, ranging from desk-top publishing and
presentation graphics to ``hypertext'' and artificial
intelligence expert systems.

     And most of what I've tried so far behaves on my Rainbow
just as it does on a comparably equipped IBM PC.

     In fact, the basic implementation of Windows on the
Rainbow is so similar to that on the IBM PC that any
generally available Windows instruction manual will serve as
a guide.  A description of Windows can be found in Nancy
Andrews'  Windows  from Microsoft Press.  To
follow her account, you need to keep in mind that on the
Rainbow Compose Character functions as ALT, and Control-
Escape functions as Escape, the general purpose cancel
command on the PC.

     Because Windows is an environment for running
applications, the main questions are which ones it runs and
how well? so I've been trying everything I could get my hands
on.

     I've tried all of the desk-top applications included in
the Windows retail package, a bunch of public domain demos
and utilities, the font, bit map, and dialogue-box editors
included with the Windows Software Development Kit, and two
major commercial packages: Windows Draw and Pagemaker.  Most
run without a hitch.

     The reason that not all do is that the current
implementation of Windows for the Rainbow is incomplete. 
Like MS-DOS, Windows comprises some code that's machine
specific and some that's not.

     The machine specific code resides in device drivers for
the computer's peripherals: keyboard, serial ports, mouse,
sound generator, and so on.  Of these, the communications
port driver turns out to be inoperable -- it crashes the
machine -- and the mouse driver has not been installed, so
programs that perform serial communications or require a
mouse won't work.

     Among the standard Windows desk-top applications, the
terminal emulator doesn't run, nor does the print spooler, 
for reasons that I haven't yet figured out.  And Pagemaker,
which does run, won't actually do page layout because all the
movement functions require a mouse.

     There are three more limitations:  The first is speed. 
It's a commonplace by now that Windows runs slowly on 8088
machines, and the Rainbow is no exception.

     Programs like Pagemaker or Draw can sometimes take a
minute or more to load and display a complex image, and some
common operations in Draw and Paint, like drawing a bounding
box, become tedious if you attempt them with the image
displayed in actual rather than reduced scale.

     The second limitation is that the version of Windows
running on the Rainbow, 1.03, was superceded last fall by
version 2.0.  The changes have been sufficient to prevent a
couple of applications written expressly for 2.0 from running
under 1.03.  These are Windows Write 2.0 (earlier versions
do run on the Rainbow) and Microsoft Excel.  In other cases,
the changes make access to the 2.0 applications' menus
cumbersome.

     Third, and perhaps least significant, the screen
drivers are monochrome;  I don't have a color monitor, but
I've been told that the screen display comes up as shade of
blue on white.

     But if the limitations of the present version are real,
its benefits are equally so.  The screen and keyboard
handling are excellent.  And the printer implementation is,
except for the spooler, complete.  All the applications I've
tried will print handsomely on the LA50 or LA75, Pagemaker
included.  I haven't tried hooking up a laser printer.

     That means that applications like Draw and Paint, for
which the mouse is recommended but optional and which do not
access the communications port, perform on the Rainbow
precisely as they were designed.

     And how many Windows applications are like Draw and
Paint?  I've only tried a few, of course, but only Pagemaker
broke the rule established in Microsoft's Windows Style Guide
that every function be accessible to a machine that lacks a
mouse.  I suspect that, at this stage of the game, most
Windows applications conform.

     There is hope, moreover, of lifting some, perhaps all,
of the present version's limitations.  The prospect of
Suitable Solutions' 286 board means that Windows's sluggish
performance on the Rainbow can soon be remedied.  I'm told a
Rainbow implementation of Windows 1.03 complete with mouse
already exists.

     And from what I've learned about the innards of Windows
and the policies of Microsoft regarding Windows-related
development, I suspect we can have, if we want it, a
completely functional and current version of Windows for
general distribution, DEC's official posture of indifference
notwithstanding.  That would mean, I believe, a greatly
extended useful life for the Rainbow.

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