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From: sdyer@bbncca.ARPA (Steve Dyer)
Newsgroups: net.micro,net.micro.pc
Subject: Re: IBM PCjr vs. Sanyo MBC555
Message-ID: <972@bbncca.ARPA>
Date: Sat, 29-Sep-84 13:50:59 EDT
Article-I.D.: bbncca.972
Posted: Sat Sep 29 13:50:59 1984
Date-Received: Tue, 2-Oct-84 02:38:13 EDT
References: <1147@eosp1.UUCP>
Organization: Bolt, Beranek and Newman, Cambridge, Ma.
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From your configuration (128K PCJr/Tecmar Jr. Captain/Multiplan) it
sounds like you are taking advantage of this month's Sears Business
Systems special.  I did the same, though I also purchased the new Sears
RGB/Composite/TV monitor (it's great! you can switch to TV during
C compilations!)  The Tecmar Jr. Captain gives you 128K more, a
clock/calendar chip and a parallel port.  This is a VERY nice deal
for $1300.

I am using this right now, and overall am wonderfully pleased.  As some
of the readers of net.micro might know, I went out and purchased a
Sanyo MBC555 a few months ago.  It is only semi-IBM compatible; pure
MSDOS-only programs (compilers, assemblers, etc.) will work fine, but
most other software which accesses the BIOS will simply not work.
The documentation is atrocious, and not a single communications program
I could find would work on it.  I still can't figure out how to do
graphics (or even access the screen) from the lame documentation.

Enter the PCJr.  I was immediately able to purchase a good VT100
emulator/XMODEM program (Mark of the Unicorn's PC/Intercomm).
The IBM PC Kermit distribution works fine, too.  Either makes a
fine remote terminal, and I have had NO problems with XMODEM
or KERMIT file transfers at 1200 baud; techies at first worried
about the non-DMA disk drive--it locks out interrupts during
transfers, meaning that many comm programs might have trouble.
Though I grant this, it hasn't been an operational problem.
Most other software I can find works fine on an expanded 256K PCJr.
Naturally, you won't be as sure about compatibility as on a PC,
but most problems arise from going beneath the BIOS to access the
graphics or disk IO ports (which aren't in the same place.)
Few programs do this.  Naturally, if a program requires two
disk drives, that will be a problem, too.  But it's surprising
what you can do with a RAM disk and one disk drive.

The new PCJr keyboard is a great improvement over the old.  As an
exercise in masochism, I used the PCJr as a remote terminal before
I received the new keyboard.  Auggh.  Now, my typing speed is back to
normal.  Both are wireless, a useless feature unless you are using
the PCJr with a projection TV.  The feel of the new keyboard is
a bit mushy compared to most; many people will still object to this.
I am not quite as picky.  I have noticed one problem with using
PC/Intercomm (though not Kermit) at 1200 baud.  A nonmaskable
interrupt is generated upon receipt of the start bit of a character
generated by the keyboard; the BIOS then acts as a software UART,
polling for bit transitions to generate the full scan code.  This
seems to cause occasional problems when I type ahead of the display:
PC/Intercomm seems to get out of sync, and generates several characters
worth of fully filled white space (VT100 DEL chars.)  This may be
due to its handling of UART overruns; I can't say yet.  I intend to
report it to MotU.

Anyway, I have found that the new keyboard and memory expansion make the
PCJr a much more desirable machine than it was before.  It also enjoys much
greater software and hardware support than the Sanyo, an equivalently
priced machine whose only advantages are 8087 support and dual disk drives,
both of which will surely be provided for the PCJr by the aftermarket.  I
am not intent on damning the Sanyo excessively; it is a nice machine, but
the hardware and software situation for it is simply nonexistent right now,
or very immature.  And even the most ardent "roll-your-own" hacker who
isn't interested in buying much software will be hampered by the
intransigence of Sanyo in providing technical documentation on the hardware
and software and the limitations of the current BIOS.  Having lived with a
non-mainstream machine for quite a while (a Radio Shack Color Computer) it
is refreshing to simply be able to buy what I need to get the job done.

The PCJr suffers when compared to the PC, and those who feel that its
limitations are unacceptable and who can afford another machine should
buy another machine.  But I think that you get a lot for the $800/$900
which the PCJr is selling for these days.
-- 
/Steve Dyer
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