Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mandrill!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Why clone the PS/2?
Summary: PS/2 hardware is better; why not clone it?
Message-ID: <1180@neoucom.UUCP>
Date: 16 May 88 13:14:12 GMT
References: <8685@eleazar.Dartmouth.EDU> <5823@well.UUCP> <10600@steinmetz.ge.com> <1642@looking.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 59


I felt that there really wasn't much reason to clone the PS/2s
until we got an IBM PS/2 model 80 in our testing lab.  We also have
a Compaq 386.

I was quite pleasantly surprised by the relative quality
construction of the model 80 compared to the other IBM branded PCs.
I never did like the original PCs and XTs.  Even the new PS/2 30
and 50s seem like consumer grade fare.  I would be reluctant to
purchase a model 50 or 60 now that IBM has leaked there intent to
realease P-9 and 80386 based machines in the latter part of 1988
and in 1989.  There are lots of Asian imports that are better deals
than the models 25 and 30, unless one needs to have VGA graphics.

The microchannel bus really is a significant technical advancement
over the orignal PC bus and should provide 5 to 10 years of
expansion potential.  Most significant is the inate ability to
handle distributed processors.  The bus is also electrically
superior to the PC bus and should make it easier for vendors to
design high performance peripheral devices.  One qualitative test
in our standard battery of trails and tribulations is to see if a
49 MHz cordless phone can be operated in the vicintiy of a given
machine.  The model 80 is the only machine that we've tested that
shows virtually no RF leakage.  We were even able to place the
phone base unit directly on the cabinet of the model 80.

Western Digital's chipset looks like it will be nice.  One
advantage is that WD's DMA channels are fully asynchonous and can
operate up to full system clock speed.  IBM's current microchannel
implemtation according to Mini Microsystems has a DMA speed limit
of 10 MHz, thus in the model 80, DMA occurs at 1/2 the system clock
(8 MHz or 10 MHz for the newer model 80).

Even more desirable than the microchannel (for the moment) is the
manufacturing trend that IBM has set with the new machines.  The
highly modular design makes servicing a snap, and will ultimately
lower costs in that department.  Since one of the things I do here
is fix machines, I like this.  ... quite a contrast to Compaq and
AT&T which appear to have been designed to be difficult to service
:-).  It is also much easier for the end user to add feature cards
to the microchannel because the physical construction of the
microchannel doesn't require special tools (Phillips screwdriver not
needed) to install the cards.  Vendors can also supply auto-install disks
that will setup the cards (presumably) painlessly .. but we've
alredy seen the fiasco with addressing 3rd party add-in memory.  So
much for that idea!

I agree that there isn't much reason for buying into the
microchannel at the moment (excep, perhaps for the model 80), but
the quality of the design makes it likely to eventaully catch on,
even if vendors have to pay tribute and tax to IBM to sell it.
Since there is a big demand for comodity-priced low end PCs, I
believe that the original PC bus will continue to live on in a
parallel universe for quite some time to come.  Just as one can
still buy regular typewriters eventhough word processors seem to be
everywhere.

--Bill
  wtm@neoucom.UUCP