gmadison@pnet02.cts.com (George Madison) (03/14/89)
Here's a discussion from GEnie, about the Model 4 and the possibility of a Tandyredesign using the Zilog Z-280 chip. Has anyone else heard these rumours,
and can anyone provide more info?
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Topic 94 Mon Feb 13, 1989
R.COOK13 at 02:02 CST
Sub: M4 Zilog upgrade chips - 1989 rumours
The big rumour for 1988, was about the Z280 upgrade chip. It hasn't
appeared yet, but some of us still wish for it. Will 1989 be the magic year --
when our dreams come true???
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R.COOK13 at 02:15 CST
Once upon a time there was a plan to upgrade the M4 by installing the Z800
Zilog chip, but the chip was never produced.
Then HI-Tech Research introduced the XLR8er board, which used the NEC
HD64180 chip (a Japanese produced version of the Zilog 80180 (Z180) This board
is still being marketed by MISOSYS, Inc.
There still exists the possibility of further upgrade boards using the
Zilog Z180 or Z280 chips. But will any be produced???????
=R=
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J.K.BEARD at 00:29 EST
The Z280 has been out for a year. I have a 10 MHz one that fell down behind
my HD and hasn't been seen since; they introduced a 20 MHz version about a
week later. There's another 64K back there, too ... ---Jim Beard---
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R.COOK13 at 01:11 CST
I realize that the Z280 chip is presently available, but there are those of
us who need an upgrade board. I for one am not a hardware hacker, and not
ashamed to admit it.
Does anyone know of any serious attempt to develop a M4 upgrade board, using
the Z280 chip? How about a single board computer using this chip?
==Roger=
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GEORGE.M at 21:11 PST
What would probably be a better idea (though more expensive) would be a brand-
new motherboard that would fit into the machine in place of the existing unit.
You could "push" a lot further if you didn't have to deal with the limitations
of the original motherboard, AND you could toss in little goodies like maybe
building in a Tandy-workalike HiRes graphics "board", and so on.
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J.K.BEARD at 01:09 EST
The Z280 has been available for over a year now. Why not a Model 4/280?
Well, Tandy holds the patent on the Model 4, which includes the I/O port
mapping, ROMs, and other hardware stuff that defines compatibility.
Tandy sells a vast computer line:
Color Computer--Motorola 6809 chip, color graphics oriented,
OS-9 optional. $200 bare, No HD, multiple floppy/OS-9 route
expensive.
Model 1000--8086 or 80286, $800 to $1200, PC clones
Model 1200--8086, PC-XT clone, PS 2 compatibility (ISA bus).
Model 3000--80286, PC-AT clone, PS 2 compatibility (EISA bus).
Model 4000--80386, OS-2 clone with EISA bus (EISA bus).
Model 6000--Motorola 68000 based, XENIX multiuser business computer.
Various portable and laptop configurations, all MS-DOS types.
The Model 4 pushes on both the CoCo line and the Model 1000 line. Also, Zilog
is years late with the Z280 (the 1983 Model 4 was designed to take one on the
motherboard!) and Tandy has lost patience with Zilog. So, Tandy is phasing
out the Model 4 in favor of upward expansion of the CoCo line and downward
expansion of the Model 1000 line. You will NOT get cooperation from Tandy.
Roy Soltoff/MISOSYS, which sells LS-DOS 6.3 and is the principal supporter of
the Model 4, is a dealer of XLER8 boards, which use the NEC 68180 (Zilog Z180)
chip. He has invested in a lifetime supply of these boards for resale, and
will not disucss the Z280.
A Model 4P-type board, which uses its own ROM but has I/O port assignment
compatiblity with the Model 4, would probably not attract legal attention from
Tandy. But, the market for Z280 motherboards, which would go at $400 or so,
is slim enough to discourage entrepreneurs.
I think that a good idea would be an ISA (16-bit IBM expansion bus) card which
included a 25 MHz Z280, an 80387 or 68882, and which could use an AT clone as
a peripheral. This would run existing software, and would open up all the
cheap hardware in the PC clone world to the Model 4 hardware/software. The
cost would be less, too. ---Jim Beard---
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J.K.BEARD at 23:11 EST
I didn't mean to be too pessimistic. Hi-Tech may use the Z280 when the
current production of XLR8 boards runs out. Tandy may just go for it on their
next production run of Model 4's. But, the best bet is a Ciarca cult or Hi-
Tech. ---Jim Beard---
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GEORGE.M at 08:13 PST
You mean there may BE another production run of M4's??? If Tandy does indeed
do that, I may be tempted into moving over from my trusty 4P... Because with
the HiRes board in my machine, AND the internal modem, there is no place to
put an accelerator board.
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J.K.BEARD at 03:45 EST
If the current supply of Model 4D boards is sold out, Tandy WILL do a
redesign, for the purposes of reducing costs. So long as the Z80A looks like
the lowest cost alternative to support their contractual obilations to the
school market, that will be their answer.
If Tandy had the viewpoint that a Z280 design would fulfil their contractual
obligations, or that it would make them money, they would do it in a minuite.
You need to understand that a Z280 machine would threaten the low end of the
8086 market (the Tandy 1000 line) as well as the high end of the 8 bit market
(the CoCo line). This, apparently, is the reason that Tandy will not have
anything to do with the Z280 in 1989.
Anyone from Tandy in rebuttal???? ---Jim Beard---
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J.FOWLER [--- John ---] at 00:20 MST
I always knew the schools were what was keeping the Model 4D alive. But, of
course, Tandy has been trying as hard as it can to get schools to switch over
to MS-DOS machines, and the advent of a Z280 would only make Tandy less able
to convince the schools to this side. Oh well, we can always dream.
--- John ---
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GEORGE.M at 23:56 PST
Does anyone have any info on the relative costs of the Z80A and the Z280?? I
seem to recall hearing that the Z280 has circuitry on board that would make a
significant amout of stuff on the existing motherboard redundant -- and THAT
would lower chip count, and therefore cost, while tending to improve
reliability -- as well as improving performance. What I'd really like to see
(pipedream time!) is a 4/280 put in a case like the T1000 series, with the
detatched keyboard, space INTERNALLY for all sorts of add-ons, including hard
drives, etc. Also, build in an uprated version of the HiRes board, perhaps
along the lines of Steve Ciarcia's GT-180 that would do color.
I don't know if Tandy realizes how many of us would actually BUY such a
machine if they actually brought it out. If it were priced anything
resembling a reasonable figure (pipedream #2), I'd scrape up the $$$ for one
in a flash.
Here's a discussion from GEnie, about the Model 4 and the possibility of a Tandyredesign using the Zilog Z-280 chip. Has anyone else heard these rumours,
George Madison, a/k/a George The Bear Cub, a/k/a Furr
INET: gmadison@pnet02.cts.com PLink: BeardLover GEnie: GeorgeM
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