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Fully Functional IMSAI-8080 boot CP/M 80 for sale on e-bay

Fully Functional IMSAI-8080 boot CP/M 80 for sale on e-bay

http://cgi.ebay.com/Fully-Functional-IMSAI-8080-boots-CP-M-in-Great-Cond_W0=
QQcmdZViewItemQQ_trkparmsZ72Q3a1234Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a131=
8Q7c301Q3a0Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem41460f=
8155QQitemZ280348295509QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported
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5/21/2009 7:28:18 AM
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Michael wrote:
> Fully Functional IMSAI-8080 boot CP/M 80 for sale on e-bay
> 
> http://cgi.ebay.com/Fully-Functional-IMSAI-8080-boots-CP-M-in-Great-Cond_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1234Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a0Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem41460f8155QQitemZ280348295509QQptZLHQ5fDefaultDomainQ5f0QQsalenotsupported

I guess you are the seller. The price is... extraordinary ... $1600 as 
start price, buy-it-now $3000 ...

Peter
0
z80eu (294)
5/21/2009 8:25:12 AM
> I guess you are the seller. The price is... extraordinary ... $1600 as 
> start price, buy-it-now $3000 ...

That's what they go for.  If you have a working Altair or IMSAI
with floppy drives (or even without) you'd sell for less than $1600, 
I'd like to hear about it!

In fact, if it wasn't for the BIN, I'd be surprised if he couldn't 
get more than $3000 for it.

Fully functional S-100 systems made by Altair and IMSAI
go for very high prices.  If there was a working Cromemco
system in an IMSAI-style chassis (remember those?) it could
easily go for over $5000.

Tom Lake
 
0
tlake (477)
5/21/2009 9:36:26 AM
Tom Lake <tlake@twcny.rr.com> wrote:
 
< That's what they go for.  If you have a working Altair or IMSAI
< with floppy drives (or even without) you'd sell for less than $1600, 
< I'd like to hear about it!
 
< In fact, if it wasn't for the BIN, I'd be surprised if he couldn't 
< get more than $3000 for it.

Once a bid is placed, the "buy it now" goes away, so it can
still sell for more than $3000.

-- glen 
0
gah (12851)
5/21/2009 10:55:55 AM
I doubt that such a system would bring $5,000; that would be nothing 
more than an IMSAI chassis, a ZPU card, memory (not necessarily 
Cromemco, but for a purist it could be four 16Kz's or one 64Kz (actually 
I'd rather have non-Cromemco static memory) and a 4FDC or 16FDC.  I 
could put together two of those.  I don't think that they would bring 
anything like $5,000.  But if anyone is willing to spend $5,000 on such 
a configuration, contact me and it's yours (I don't have a disk drive 
system, per se, but I can throw in a pair of Tandon TM848 drives).

Tom Lake wrote:
> 
> 
> Fully functional S-100 systems made by Altair and IMSAI
> go for very high prices.  If there was a working Cromemco
> system in an IMSAI-style chassis (remember those?) it could
> easily go for over $5000.
> 
> Tom Lake
> 
0
WatzmanNOSPAM (5711)
5/24/2009 8:43:27 PM
That is correct, and it happens A LOT; someone places a bid above the 
starting price but below "buy it now", "buy it now" disappears, and the 
bidding then goes above (sometimes WAY above) what the buy it now price 
had been.  Very common.


glen herrmannsfeldt wrote:

> 
> Once a bid is placed, the "buy it now" goes away, so it can
> still sell for more than $3000.
> 
> -- glen 
0
WatzmanNOSPAM (5711)
5/24/2009 8:44:43 PM
I repeat:  if anyone is willing to spend $5,000 on such
a configuration, contact me and it's yours.

[The silence is deafening .....]

Barry Watzman wrote:
> I doubt that such a system would bring $5,000; that would be nothing 
> more than an IMSAI chassis, a ZPU card, memory (not necessarily 
> Cromemco, but for a purist it could be four 16Kz's or one 64Kz (actually 
> I'd rather have non-Cromemco static memory) and a 4FDC or 16FDC.  I 
> could put together two of those.  I don't think that they would bring 
> anything like $5,000.  But if anyone is willing to spend $5,000 on such 
> a configuration, contact me and it's yours (I don't have a disk drive 
> system, per se, but I can throw in a pair of Tandon TM848 drives).
> 
> Tom Lake wrote:
>>
>>
>> Fully functional S-100 systems made by Altair and IMSAI
>> go for very high prices.  If there was a working Cromemco
>> system in an IMSAI-style chassis (remember those?) it could
>> easily go for over $5000.
>>
>> Tom Lake
>>
0
WatzmanNOSPAM (5711)
5/28/2009 2:29:33 AM
"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message 
news:gvksul$dtp$5@news.eternal-september.org...
> I repeat:  if anyone is willing to spend $5,000 on such
> a configuration, contact me and it's yours.
>
> [The silence is deafening .....]

If it's ALL Cromemco (including the Cromemco-labeled IMSAI styled case)
list it on eBay.  Most people here either already have the system they want 
or
could build it themselves.  On eBay you'd get bids from collectors who
put a premium on complete stock vintage systems (especially those that
include original docs.)

Tom Lake

--
If you go into a corn field and can't find your way out again,
are you lost in the maize?

 

0
tlake (477)
5/28/2009 5:23:11 AM
In article <gvksul$dtp$5@news.eternal-september.org>,
	Barry Watzman <WatzmanNOSPAM@neo.rr.com> writes:
> I repeat:  if anyone is willing to spend $5,000 on such
> a configuration, contact me and it's yours.
> 
> [The silence is deafening .....]

I would love to have an IMSAI, but certainly not for $5000.
I may be a geek and a dinosaur, but I'm not an idiot.  :-)

bill

-- 
Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
billg999@cs.scranton.edu |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>   
0
billg999 (2588)
5/28/2009 10:53:01 AM
"Bill Gunshannon" <billg999@cs.uofs.edu> wrote in message 
news:7878odF1l56h8U2@mid.individual.net...
> In article <gvksul$dtp$5@news.eternal-september.org>,
> Barry Watzman <WatzmanNOSPAM@neo.rr.com> writes:
>> I repeat:  if anyone is willing to spend $5,000 on such
>> a configuration, contact me and it's yours.
>>
>> [The silence is deafening .....]
>
> I would love to have an IMSAI, but certainly not for $5000.
> I may be a geek and a dinosaur, but I'm not an idiot.  :-)

It's not being an idiot.  If you collect things and have the money
to pay for them, no justification is needed.  $10,000.00 for a stamp isn't
worth it to me but there are stamps that sell for that much and more
to collectors.  Do I think they're idiots for paying that much?  No.
They enjoy the stamps so let them have their fun.  I'm sure some things
I collect (much cheaper!) would baffle them as to why anyone would want
something like that.  Just because someone places value differently than
you or I do doesn't make them wrong, foolish or an idiot, just different.

Tom Lake 

0
tlake (477)
5/28/2009 12:15:39 PM
Bill,

Re: "I may be a geek and a dinosaur, but I'm not an idiot.  :-)"

We screw that.  I'm only looking for a 1st class idiot (with $5,000 or 
more).

Barry

PS - Idiot offer #2 (also $5,000):  An original copy of 86-DOS with all 
manuals and original disks, multiple versions from 0.33 to 1.25 (and 
perhaps later).


Bill Gunshannon wrote:
> In article <gvksul$dtp$5@news.eternal-september.org>,
> 	Barry Watzman <WatzmanNOSPAM@neo.rr.com> writes:
>> I repeat:  if anyone is willing to spend $5,000 on such
>> a configuration, contact me and it's yours.
>>
>> [The silence is deafening .....]
> 
> I would love to have an IMSAI, but certainly not for $5000.
> I may be a geek and a dinosaur, but I'm not an idiot.  :-)
> 
> bill
> 
0
WatzmanNOSPAM (5711)
5/28/2009 3:26:51 PM
On May 24, 1:43 pm, Barry Watzman <WatzmanNOS...@neo.rr.com> wrote:
> I doubt that such a system would bring $5,000; that would be nothing
> more than an IMSAI chassis, a ZPU card, memory (not necessarily
> Cromemco, but for a purist it could be four 16Kz's or one 64Kz (actually
> I'd rather have non-Cromemco static memory) and a 4FDC or 16FDC.  I
> could put together two of those.  I don't think that they would bring
> anything like $5,000.  But if anyone is willing to spend $5,000 on such
> a configuration, contact me and it's yours (I don't have a disk drive
> system, per se, but I can throw in a pair of Tandon TM848 drives).
>
> Tom Lake wrote:
>
> > Fully functional S-100 systems made by Altair and IMSAI
> > go for very high prices.  If there was a working Cromemco
> > system in an IMSAI-style chassis (remember those?) it could
> > easily go for over $5000.
>
> > Tom Lake

Hi
 What I don't get is why a bastardized IMSAI has more value than an
original. It is true that the Z80 cards are faster but if that is all
one
wants, why not buy something like a Kaypro II and just run CPM on
that?
 For me, I treasure an IMSAI with the original CPU and one of the
original
disk systems, such as IMSAI's or Digital Systems. Running on one
of these may not be fast but I have other machines to run things
fast on. It is more the pleasure of knowing that I'm running
something that was the state of the art when IMSAIs first got started.
Dwight
0
dkelvey (274)
5/29/2009 7:48:28 PM
In article <dd8844a4-0420-45c9-b52b-f34482935888@o20g2000vbh.googlegroups.com>,
	"dkelvey@hotmail.com" <dkelvey@hotmail.com> writes:
> On May 24, 1:43 pm, Barry Watzman <WatzmanNOS...@neo.rr.com> wrote:
>> I doubt that such a system would bring $5,000; that would be nothing
>> more than an IMSAI chassis, a ZPU card, memory (not necessarily
>> Cromemco, but for a purist it could be four 16Kz's or one 64Kz (actually
>> I'd rather have non-Cromemco static memory) and a 4FDC or 16FDC.  I
>> could put together two of those.  I don't think that they would bring
>> anything like $5,000.  But if anyone is willing to spend $5,000 on such
>> a configuration, contact me and it's yours (I don't have a disk drive
>> system, per se, but I can throw in a pair of Tandon TM848 drives).
>>
>> Tom Lake wrote:
>>
>> > Fully functional S-100 systems made by Altair and IMSAI
>> > go for very high prices.  If there was a working Cromemco
>> > system in an IMSAI-style chassis (remember those?) it could
>> > easily go for over $5000.
>>
>> > Tom Lake
> 
> Hi
>  What I don't get is why a bastardized IMSAI has more value than an
> original. It is true that the Z80 cards are faster but if that is all
> one
> wants, why not buy something like a Kaypro II and just run CPM on
> that?

I agree.  I would love an IMSAI "8080".  :-)

>  For me, I treasure an IMSAI with the original CPU and one of the
> original
> disk systems, such as IMSAI's or Digital Systems. Running on one
> of these may not be fast but I have other machines to run things
> fast on. It is more the pleasure of knowing that I'm running
> something that was the state of the art when IMSAIs first got started.

Wasn't Tarbell one of the first disk systems?  Or has my memory
finally started melting down?

bill

-- 
Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
billg999@cs.scranton.edu |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>   
0
billg999 (2588)
5/29/2009 8:51:13 PM
Tarbell was not really an early disk system, but was a very popular disk 
controller once they came out (1977, I think; well after North Star, 
Digital Systems, Imsai and others).  They didn't make a "disk system", 
they made a "disk controller"; supply your own drives.  And kit form only.

There were two Tarbell controllers, a single density controller and a 
double density controller, both based on Western Digital chips (1771 and 
1793).  The single density controller was almost a wire-wrap board with 
maybe 100 jumper points.  This was because, at that time, drives were 
not standardized (NOTHING was standard, not even the connector or the 
number of wires in the cable).  By the time the double density board 
came out, things had settled down and the shugart 50-pin interface 
standard was well established.

The single density board was a VERY good disk controller, if you could 
get it configured properly.  It was, however, intended for 8" drives 
only (as was the double density board).  But it was possible to modify 
the board(s) to support 3.5" drives, what you could not do, however, was 
support both drive types on a single controller card.

The double density board was very sophisticated, with an 8257 DMA 
controller for data transfer (it could also do programmed data transfer 
if desired).  Unfortunately, the board went through a LOT of revisions 
.... versions before revision "E" were just plain flaky, and Tarbell 
continued "fixing" the board up through at least a revision "H". 
Another problem with the double density board was that it only had one 
power regulator, and it was ***WAY*** over-stressed by the huge amount 
of circuitry on the board and it would burn up (and burn up the board 
..... literally, charred) in many cases.  Common practice was to put a 
2-Watt low value resistor (4.7 to 10 ohms)across the back of the 
regulator to provide a bit of relief.



Bill Gunshannon wrote:

> 
> I agree.  I would love an IMSAI "8080".  :-)
> 
>>  For me, I treasure an IMSAI with the original CPU and one of the
>> original
>> disk systems, such as IMSAI's or Digital Systems. Running on one
>> of these may not be fast but I have other machines to run things
>> fast on. It is more the pleasure of knowing that I'm running
>> something that was the state of the art when IMSAIs first got started.
> 
> Wasn't Tarbell one of the first disk systems?  Or has my memory
> finally started melting down?
> 
> bill
> 
0
WatzmanNOSPAM (5711)
5/29/2009 11:18:02 PM
Most people who want an old computer wants a system with a front
panel. The front panel take one back to a time when you could almost
watch the CPU executed its instructions. With the IMSAI-8080, Altair
8800 and their likes you really get to take yourself back to the days
of toggling in binary programs to boot strap the system. Because of
there shape, colors and blinking light have estetic value much like
the Apples computers of today.

Old systems like CompuPro and Cromemco however better made their
products were are simply computers in ugly little boxes that the
average person does not care about; much like the typical PC box; it
just functional.

When I have people comes to visit me they totally ignore my CompuPro
816 box and admire the IMSAI-8080, ALTAIR-8800 and for that matter my
H8. The CompuPro 816 might as well not be in the room. In the mind of
the average person visiting my home those three boxes are functional
artwork with personalities; the personalities primarily comes from the
blinking lights of their front panels.

So there you have it CompuPro and Cromemco for all their technical
merits will end up in the junk heap like so many ugly PC's and MAC's.
No one cares for a ugly box.

Back to the point IMSAI-8080, ALTAIR-8800 and H8 are being valued by
the average collector more on estetic value than technical merits.
When the non-technical friend having no historic perspective comes and
visit they are entertained by the the lights and activity of the
floppy drives and want one for themself thereby increasing the value
of my front panel systems.


0
5/30/2009 11:24:26 AM
Michael wrote:

> Most people who want an old computer wants a system with a front
> panel.

Several years ago, when corresponding with an American who wanted to
build yet-another Z-80 CP/M computer, I wrote him that, without a
front panel, his dream computer was doomed. I am still of this
opinion. It wonder if Andrew Lynch made one for his N8VEM?

As Lee Hart explained, the front panel can even test the components of
a system without a working CPU. It is a very versatile hardware
debugging tool.

And it certainly looks different than an IBM Clown.

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
5/30/2009 4:13:43 PM
Off the topic

> opinion. It wonder if Andrew Lynch made one for his N8VEM?
But have a look

http://n8vem-sbc.pbworks.com/

Give the man credit for his perseverance
0
5/30/2009 6:42:53 PM
> Old systems like CompuPro and Cromemco however better made their
> products were are simply computers in ugly little boxes that the
> average person does not care about; much like the typical PC box; it
> just functional.

The first Cromemco computer did have a front panel.  It was a 
relabeled IMSAI box.

Tom Lake 
0
tlake (477)
5/31/2009 4:01:30 AM
I've supported S-100 for many years, and still do. While I understand
Michael's comments, I think they are a little harsher than they need
to be. And, to make a personal comment, I think Michael is showing
some personal bitterness that some of his S-100 collection is not
appreciated - I understand that feeling myself. So I'll take part of a
Sunday afternoon to stay inside to respond, rather than have a nice
sunny morning outside as I should.

Now, it's factual that "most people" and "many people" find S-100
systems without front panels to be boring, and find IMSAI's and
Altairs with front panels to be attractive. But I suggest to my
"vintage" computer colleagues, that "most people" are clueless about
computing, technology, history, etc. etc. And even those who should be
familiar with computing history - technologists and technical
reporters over say 50 - are often bored by old computers altogether,
"blinkenlights" or not. They think (or say in public) personal
computing began with the IBM PC and the Mac 128K. Maybe, the Apple II.
Because that's popular.

So, why should we give a rat's ass about "most people"? Michael offers
the only reason - they will pony up big money to buy the
"blinkenlights" systems.  "Back to the point: IMSAI-8080, ALTAIR-8800
and H8 are being valued by the average collector more on aesthetic
value than technical merits." That must explain their eBay prices. How
about that - people like pretty lights. I see that every Christmas,
Michael.

But I disagree with his conclusion: all the non-blinking computers
will be scrapped out, no one cares about them, they are boring.
Michael, I don't let what "most people" think run *my* life. And, if
hobbyists of almost any kind accepted the "most people think your
hobby is boring" argument, that would end most hobbies. Period.

So, I reject your argument that "old systems like CompuPro and
Cromemco, however better made, their products were are simply
computers in ugly little boxes".

They are not ugly *to me*, Michael. Nor to many other people who have
those boards and systems. Check the Web, look for the images yourself.
I share your grief that "most people" have no interest in them, but I
don't use their lack of interest to drive *my interests*. My interest
in these systems is not based on some glim-glam impression of lights
and switches. It's based on the "aesthetic" of *technical design and
development*; on their place in computing history; on my ability to
test and repair them chip by chip; and so on. I suspect other
collectors and owners have one or more of these considerations in
mind, and other considerations. In *any* hobby, Michael: the more you
know about function and history, the more interesting your hobby
becomes. And when one participates in a hobby, interest and
satisfaction grows too.

I'm sorry that depth of knowledge is not fashionable today.

As to why people would buy these things. I find some people have these
"ugly little boxes" today, in part because they wanted them at the
time and could not afford them: now they can. So, why did they want
them at the time? Michael, there was a time when *personal computing
did not exist*. Then these "ULB's" became available - that was
exciting! First, to the technical community; then to the business
community; and then to your "ordinary people". And these "ULB's" was
*where that began* - outside the minicomputers and mainframes that
were out-of-reach for most any individual to own. You could OWN A
COMPUTER - in the 1970's that was the ultimate techie achievement!

Isn't that interesting, Michael?

Now, if "most people" find a paragraph or two of history as "boring";
if they lack the attention span to read them, or lack depth of
interest in the past to look back....in my opinion, that's a comment
upon them, not me. BUT, as I get older, I feel more of an obligation
to address the "facts" such as these, such as Michael describes. The
"ULB's" need some explanation, and one needs some background about
them, for them to be of interest once again. I"ve already said why we
should bother - it's ultimately about *preserving history*. When you
are old, you think about what happens after you are gone.

One reason I spent a few years on my Web site, in outlining the
history of CP/M development, was because those historic facts, about
that particular technology, were becoming scattered and unavailable.
That history was not "pretty", it was about dead people who didn't get
rich (enough), it was about "ULB's". The facts would become *lost*
from lack of interest. Now, I don't think so - my Web pages and
others, the activity of discussion in comp.os.cpm and elsewhere, the
relative ease to archive documents and code, the stability of those
archives and mirroring of content, and all the emulators built to run
the software.

Now, I'm worried about preserving *hardware*. Not just as a pile of
"ULB's" and a few "blinkenlights", but as artifacts with a history and
legacy, and as technology that is *accessible to most any one person
today*. In my opinion, now we who are still interested, are obliged to
make the case for the future, in a world where computing is taken for
granted, and where "old computer" equals "scrap".

 I don't blame Michael for "bearing bad news". His observations cannot
be denied or ignored. But when he concludes (at least in his post) to
give up his collection of "ULB's" and scrap them out, it diminishes my
hobby, it reduces the value of our interest in them, and it deletes a
part of history. That's a loss for all of us.

Herb Johnson
retrotechnology.com


0
herbrjohnson (355)
5/31/2009 4:28:25 PM
On Sat, 30 May 2009 09:13:43 -0700 (PDT), "Mr Emmanuel Roche, France"
<roche182@laposte.net> wrote:

>Michael wrote:
>
>> Most people who want an old computer wants a system with a front
>> panel.
>
>Several years ago, when corresponding with an American who wanted to
>build yet-another Z-80 CP/M computer, I wrote him that, without a
>front panel, his dream computer was doomed. I am still of this
>opinion. It wonder if Andrew Lynch made one for his N8VEM?
>
>As Lee Hart explained, the front panel can even test the components of
>a system without a working CPU. It is a very versatile hardware
>debugging tool.
>

One little error there.  If the CPU is nonfuctional or minimally
crippled the front pannel is mostly useless.  It depends on the CPU
board being fully functional and any board plugged in must not 
corrupt the bus of the front pannel function will not behave.

Front panels were a legacy of the days when Eproms were 1702
a whopping 256 bytes and  cost as much as the 30 odd switches
needed for the front panel which at the time were about $1 in
quantities of 1000.  It wa a way to avoid creating software support
for debug and  was quickly eclipsed by systems of greater
functionality.

Even the Altair 8800B had a front panel less version (BT)
and it was considered quite attractive and more reliable.

Allison


>And it certainly looks different than an IBM Clown.
>
>Yours Sincerely,
>Mr. Emmanuel Roche, France

0
Allison5973 (238)
5/31/2009 7:33:16 PM
> >As Lee Hart explained, the front panel can even test the components of
> >a system without a working CPU. It is a very versatile hardware
> >debugging tool.
>
> One little error there. =A0If the CPU is nonfuctional or minimally
> crippled the front pannel is mostly useless. =A0It depends on the CPU
> board being fully functional and any board plugged in must not
> corrupt the bus of the front pannel function will not behave.

Lee Hart wrote (24 November 2002):

The beauty of a true front panel is that it worked even when the
computer didn't. If the computer didn't work, you could still use the
front panel to examine or change memory or I/O, single-step the CPU,
etc. Even simple test equipment (a meter, logic probe, or simply an
LED
and resistor) could be used to check all the signals until you found
the
problem.

All my early computers had front panels that basically imitated the
actual CPU, or that held the CPU in infinite 'wait' states (for CPU
and
memory chips that are static, like the Z80).

Plain old LEDs and toggle switches have advantages over hex displays
and
keypads. First, they are simpler; and the simpler it is, the less
there
is to go wrong. Second, there are many times at the hardware level
when
you want to know what one particular line is doing, and converting
the
entire bus to hex only confuses things.

Lee Hart also wrote (26 November 2002):

The front panel on my first microcomputer was basically a set of
toggle
switches and tri-state drivers to set the address and data to write
to
the bus; and a corresponding set of latches and LEDs to capture and
display the address and data coming back from the bus. Some simple
logic
and one-shots generated the read, write, memory, and I/O strobes. It
worked even with no CPU in the socket.

And finally, the 29 November 2002, Lee Hart wrote:

Perhaps it would be worthwhile to describe the front panel I built
for
my first Z80 computer. I built all the cards on the 6.5" x 4.5" perf
boards with a 22/22 pin edge connector on one end. Each board had one
function (CPU, memory, I/O, power supply, etc.).

The front-most board was the front panel. Since the Z80 was over $100
at
the time I started, I built the front panel mainly to test my memory
and
I/O cards before I put that priceless Z80 in it.

There were eight CMOS 4042 quad latches with their inputs connected
to
the 16 address, 8 data, and 8 control lines. Each output had an LED
to
display the status of its respective line as of the last time the
4042
was latched. There were also 32 toggle switches, connected to eight
CMOS
4016 quad SPST analog switches to the same address, data, and control
lines. And, a clock oscillator whose frequency could be set with a
pot.

To read a memory location, I set the address switches, and switched
/MREQ and /RD to simulate the Z80 timing. Likewise to read. Same for
I/O. If a real Z80 was present, I made it get off the bus by pulling
the
/BUSRQ pin low. Though tedious, the advantage was that I knew EXACTLY
how it worked, and could watch it with the LEDs. The Z80 is static
(or
close to it), so I could even clock it at 1 Hz and watch the timing
diagrams real-time without an oscilloscope!

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
5/31/2009 8:18:48 PM
>The beauty of a true front panel is that it worked even when the
>computer didn't. If the computer didn't work, you could still use the
>front panel to examine or change memory or I/O, single-step the CPU,
>etc.

Amen!  I learned a lot of the IBM 1130's architecture
via the front panel and the manuals,
running it single instruction,
single memory cycle (1-4 per instruction),
single clock cycle (follow the flowchart per instruction!)
The CPU was halted so the panel
accessed core as desired.

Years later, I worked on a DSP where the hardware
was only debugged via the front panel,
which asserted control of the bus,
thus unable to see any signals
internal to the CPU such as registers :-(
THAT was why self-modifying code was discouraged:
the resulting instruction never went on the bus
(register-to-register) so it could not be observed.

> Plain old LEDs and toggle switches have advantages over
> hex displays and keypads.
> First, they are simpler; and the simpler it is, the less there
> is to go wrong. Second, there are many times at the hardware level
> when you want to know what one particular line is doing,
> and converting the entire bus to hex only confuses things.

I don't miss toggling in things bitwise.
Hey keypads are much nicer.
But when programs are running,
reading toggle switches for options is VERY NICE.

IBM mainframes were bitwise displays
but had rollers to select what to display
and labelled each indicator with the bit's meaning.
Yes, that was nice for watching particular bits in status words.
But hex is better for anything where >4 bits form a field.
Even the Heathkit CPU trainers used 7 segment LED displays
for hex to keep the parts count down
and for a more general purpose display.


>Lee Hart also wrote (26 November 2002):

> The front panel on my first microcomputer was basically a
> set of toggle switches and tri-state drivers
> to set the address and data to write to the bus;
> and a corresponding set of latches and LEDs to capture and
> display the address and data coming back from the bus.

When I breadboarded my first Z80,
I was lulled into making such a front panel
(inspired by the Altair, Imsai which I had only seen in ads,
and by mostly using minicomputers with front panels).
I had no tolerance for such drudgery and during construction,
I realized that using toggle switches and LEDs would be
even more drudgery, so I gave up and used a Timex Sinclair 1000
as the front panel (since it too was a Z80 inside).
I was much happier.
A classmate made a tiny monitor in EPROM but had to hand-toggle
that into the ROM using his own EPROM programmer.
As time would tell, he had the right idea,
since even my PIC-18 runs that way with an RS232 serial link
to a boot-loader in protected flash ROM.

> Some simple logic and one-shots generated the read, write,
> memory, and I/O strobes.

It's not so simple when the panel ages!
I saw the folks at MARCH (NJ computer museum at Camp Evans)
debugging/repairing an Altair's front panel
that was no longer generating the required S100 signals.


>Perhaps it would be worthwhile to describe the front panel I built
>for my first Z80 computer. I built all the cards on the 6.5" x 4.5"
>perf boards with a 22/22 pin edge connector on one end.
>Each board had one function (CPU, memory, I/O, power supply, etc.).

>The front-most board was the front panel.
> Since the Z80 was over $100 at the time I started,
> I built the front panel mainly to test my memory and
>I/O cards before I put that priceless Z80 in it.

I had similar feelings even though the Z80 was more affordable
by 1983.  But that was MY money so I was super cautious!

>There were eight CMOS 4042 quad latches with their inputs
>connected to the 16 address, 8 data, and 8 control lines.
>Each output had an LED to display the status of its respective line
>as of the last time the 4042 was latched.
>There were also 32 toggle switches, connected to eight
>CMOS 4016 quad SPST analog switches to the same address, data,
>and control lines. And, a clock oscillator whose frequency
>could be set with a pot.

Nice!

>To read a memory location, I set the address switches, and switched
>/MREQ and /RD to simulate the Z80 timing. Likewise to read.
>Same for I/O. If a real Z80 was present,
>I made it get off the bus by pulling the /BUSRQ pin low.

I did that since the CPU then tri-stated all bus controls.
I hope I used /BUSACK to trigger my front panel to assert control
so it didn't jump the gun while the CPU was still active.

>Though tedious, the advantage was that I knew EXACTLY
>how it worked, and could watch it with the LEDs.
>The Z80 is static (or close to it),
>so I could even clock it at 1 Hz and watch the timing
>diagrams real-time without an oscilloscope!

Ya, I lost that feature using the T/S 1000 as a front panel,
but I debugged via examining memory and poking the hex display.
0
jeffj (156)
6/1/2009 3:56:10 AM
On May 30, 7:24=A0am, Michael <michael.george.h...@gmail.com> wrote:
>
> So there you have it CompuPro and Cromemco for all their technical
> merits will end up in the junk heap like so many ugly PC's and MAC's.
> No one cares for a ugly box.
>

'Suppose that makes me no one, then.  I'll gladly take any Cromemco
system you don't want any more. I happen to value those machines
significantly more than any of the altair/imsai genre.  You might even
say I like the way they look.  But in all truthfulness, I just like
how they work and what they can run (I grew up on Cromix).  As
blasphemous as it may sound, I even like the IBM PC.  Heck it can even
run CP/M.

Furthermore, I have to agree with Herb.  What others think,
particularly those without a finely developed sense of computer
nostalgia, do not have any impact on how much I enjoy this hobby.
That the systems I'm interested in come at a reasonable price due to
their lacking certain panel ornaments... we'll I'm just grateful for
that.

Amardeep
0
asc135 (27)
6/1/2009 4:33:56 AM
> Furthermore, I have to agree with Herb.  What others think,
> particularly those without a finely developed sense of computer
> nostalgia, do not have any impact on how much I enjoy this hobby.
> That the systems I'm interested in come at a reasonable price due to
> their lacking certain panel ornaments... we'll I'm just grateful for
> that.

Unfortunately (for my wallet) , my nostalgia is for systems with a 
full front panel.  I am quite willing to pay to indulge my wants.
My wife, not so willing 8^)  After my daughter gets married at the 
end of this month, I'll again go on a hedonistic spree of avarice
the likes of which eBay hasn't seen since the economy tanked.

Tom Lake
--
If some is good, more is better!

Lust, Sloth, Greed, Gluttony - I only have four out of the seven
but I'm working on it.
 
0
tlake (477)
6/1/2009 4:44:24 PM
Mr Emmanuel Roche,wrote:
> > >As Lee Hart explained, the front panel can even test the components of
> > >a system without a working CPU. It is a very versatile hardware
> > >debugging tool.
>
> [Allison wrote:]
> > One little error there. =A0If the CPU is nonfuctional or minimally
> > crippled the front pannel is mostly useless. =A0It depends on the CPU
> > board being fully functional and any board plugged in must not
> > corrupt the bus of the front pannel function will not behave.
>
> Lee Hart wrote (24 November 2002):
>
> The beauty of a true front panel is that it worked even when the
> computer didn't.

Emmanuel, Lee's Hart's front panel operated independently of the
system Z80 processor. He said as much, in the post you copied to
comp.os.cpm. In the S-100 world, where most Z80 front panels we see
today were in use, most front panel designs force the Z80 (or 8080)
processor to perform bus operations. Consequently, Allison's statement
is correct in that context. Read the manuals for specifics. But,
thanks for providing some description of yet another front panel
design.

herb johnson
retrotechnology.com

0
herbrjohnson (355)
6/1/2009 6:24:53 PM
Barry Watzman wrote:
> Barry Watzman wrote:
>> Tom Lake wrote:
>>>
>>> Fully functional S-100 systems made by Altair and IMSAI go for
>>> very high prices.  If there was a working Cromemco system in an
>>> IMSAI-style chassis (remember those?) it could easily go for
>>> over $5000.
>>
>> I doubt that such a system would bring $5,000; that would be
>> nothing more than an IMSAI chassis, a ZPU card, memory (not
>> necessarily Cromemco, but for a purist it could be four 16Kz's
>> or one 64Kz (actually I'd rather have non-Cromemco static
>> memory) and a 4FDC or 16FDC.  I could put together two of those. 
>> I don't think that they would bring anything like $5,000.  But
>> if anyone is willing to spend $5,000 on such a configuration,
>> contact me and it's yours (I don't have a disk drive system, per
>> se, but I can throw in a pair of Tandon TM848 drives).
> 
> I repeat:  if anyone is willing to spend $5,000 on such
> a configuration, contact me and it's yours.
> 
> [The silence is deafening .....]

Did you ever consider that the problem might be failure to be read,
due to your insistence on annoying top-posting?  :-)  (I fixed this
one.)

Another possibility is the ridiculous price.

-- 
 [mail]: Chuck F (cbfalconer at maineline dot net) 
 [page]: <http://cbfalconer.home.att.net>
            Try the download section.


0
cbfalconer (19194)
6/2/2009 1:29:35 AM
On May 29, 3:48=A0pm, "dkel...@hotmail.com" <dkel...@hotmail.com> wrote:
> On May 24, 1:43 pm, Barry Watzman <WatzmanNOS...@neo.rr.com> wrote:
>
>
>
>
>
> > I doubt that such a system would bring $5,000; that would be nothing
> > more than an IMSAI chassis, a ZPU card, memory (not necessarily
> > Cromemco, but for a purist it could be four 16Kz's or one 64Kz (actuall=
y
> > I'd rather have non-Cromemco static memory) and a 4FDC or 16FDC. =A0I
> > could put together two of those. =A0I don't think that they would bring
> > anything like $5,000. =A0But if anyone is willing to spend $5,000 on su=
ch
> > a configuration, contact me and it's yours (I don't have a disk drive
> > system, per se, but I can throw in a pair of Tandon TM848 drives).
>
> > Tom Lake wrote:
>
> > > Fully functional S-100 systems made by Altair and IMSAI
> > > go for very high prices. =A0If there was a working Cromemco
> > > system in an IMSAI-style chassis (remember those?) it could
> > > easily go for over $5000.
>
> > > Tom Lake
>
> Hi
> =A0What I don't get is why a bastardized IMSAI has more value than an
> original.
....
> Dwight- Hide quoted text -
>
> - Show quoted text -

As mentioned elsewhere, the system in question is not a relatively
common "bastardized IMSAI," but a relatively rare Cromemco Z-1. See:
http://rwebs.net/micros/Cromemco/front.htm

mike

0
dm561 (120)
6/2/2009 5:04:06 PM
On Jun 1, 9:29=A0pm, CBFalconer <cbfalco...@yahoo.com> wrote:
> Barry Watzman wrote:
> > Barry Watzman wrote:
> >> Tom Lake wrote:
>
> >>> Fully functional S-100 systems made by Altair and IMSAI go for
> >>> very high prices. =A0If there was a working Cromemco system in an
> >>> IMSAI-style chassis (remember those?) it could easily go for
> >>> over $5000.
>
> >> I doubt that such a system would bring $5,000; that would be
> >> nothing more than an IMSAI chassis, a ZPU card, memory (not
> >> necessarily Cromemco, but for a purist it could be four 16Kz's
> >> or one 64Kz (actually I'd rather have non-Cromemco static
> >> memory) and a 4FDC or 16FDC. =A0I could put together two of those.
> >> I don't think that they would bring anything like $5,000. =A0But
> >> if anyone is willing to spend $5,000 on such a configuration,
> >> contact me and it's yours (I don't have a disk drive system, per
> >> se, but I can throw in a pair of Tandon TM848 drives).
>
> > I repeat: =A0if anyone is willing to spend $5,000 on such
> > a configuration, contact me and it's yours.
>
> > [The silence is deafening .....]
>
> Did you ever consider that the problem might be failure to be read,
> due to your insistence on annoying top-posting? =A0:-) =A0(I fixed this
> one.)
>
> Another possibility is the ridiculous price.
>
> --
> =A0[mail]: Chuck F (cbfalconer at maineline dot net)
> =A0[page]: <http://cbfalconer.home.att.net>
> =A0 =A0 =A0 =A0 =A0 =A0 Try the download section.- Hide quoted text -
>
> - Show quoted text -

I think you (and a few others) missed the point...
0
dm561 (120)
6/2/2009 5:13:45 PM
On May 31, 12:28=A0pm, Herbert Johnson <herbrjohn...@gmail.com> wrote:
<much snippage>
> =A0I don't blame Michael for "bearing bad news". His observations cannot
> be denied or ignored. But when he concludes (at least in his post) to
> give up his collection of "ULB's" and scrap them out, it diminishes my
> hobby, it reduces the value of our interest in them, and it deletes a
> part of history. That's a loss for all of us.
>
> Herb Johnson
> retrotechnology.com
---------
While I mostly agree with Herb (for a change ;-) I have to also
partially agree with my namesake:

I think most of us cringe whenever we hear of a "classic" system being
scrapped, even if it's "just" an "ULB" and doesn't have a front panel.
But considering the size and weight of these old crates the reality is
that few people are even willing to pay the ever-increasing shipping
costs involved, never mind a reasonable price, unless it is a system
that is visually unique and different from the usual nondescript
generic boxes.

So, yes, mea culpa, I've scrapped a number of Cromemco boxes and will
probably be scrapping a few more because few people are willing to pay
enough to cover shipping and the time, effort and material required at
my end; sorry to be crass, but selling a few cards is a lot less
trouble and nets about the same in the end...

Does that really diminishes Herb's hobby, reduce the value of our
interest in them, and delete a part of history? There are lots of
other examples out there, in museums, public collections etc, so does
it really matter in the big picture whether I have a few more in my
basement or I reduce them to a collection of parts?

m
0
dm561 (120)
6/2/2009 5:41:16 PM
> So, yes, mea culpa, I've scrapped a number of Cromemco boxes and will
> probably be scrapping a few more because few people are willing to pay
> enough to cover shipping and the time, effort and material required at
> my end; sorry to be crass, but selling a few cards is a lot less
> trouble and nets about the same in the end...

If you have complete, working systems, please send me a list or post it!
I'd certainly consider paying for professional packing and shipping.

Tom Lake 
0
tlake (477)
6/2/2009 7:13:34 PM
On May 30, 12:13=A0pm, "Mr Emmanuel Roche, France"
<roche...@laposte.net> wrote:
> Michael wrote:
> > Most people who want an old computer wants a system with a front
> > panel.
>
> Several years ago, when corresponding with an American who wanted to
> build yet-another Z-80 CP/M computer, I wrote him that, without a
> front panel, his dream computer was doomed. I am still of this
> opinion. It wonder if Andrew Lynch made one for his N8VEM?
>
> As Lee Hart explained, the front panel can even test the components of
> a system without a working CPU. It is a very versatile hardware
> debugging tool.
>
> And it certainly looks different than an IBM Clown.
>
> Yours Sincerely,
> Mr. Emmanuel Roche, France

Hi!  Yes, Front Panels are very popular peripherals and they are
probably the most requested item in N8VEM home brew computer project.

As of now, there is an N8VEM ECB bus monitor board that allows most of
the functionality of a front panel but not all.  It is actually closer
to a "Jade Bus Probe" but for ECB rather than S-100.  The ECB bus
monitor allows various modes for STOP, START, SINGLE STEP, conditional
triggering, address trapping, etc.  It has all the LEDs for various
bus states address, data, control, and other parameters.  It allows
for builder supplied trapping of addresses and some other things
useful for program debugging.

The ECB bus monitor makes for a fascinating display of "blinkenlights"
for those into that sort of thing.  When used with the RAM monitor,
the ECB bus monitor really is great for debugging things.  I've used
it and its a lot of fun.  Especially the SINGLE STEP modes and address
trapping.  Since the Z80 is entirely static, it preserves state
without any fancy trickery.

However, the primary difference between the ECB bus monitor and the
traditional front panel is that it does not allow for arbitrary
builder injection of data at a specific address.   You can use it with
the RAM monitor to do that functionality but it means the CPU and UART
are working at a minimum.

Some of the builders are working on a project called DSKY which is a
display keyboard device which when used with the N8VEM SBC *does* give
full front panel functionality.  It works with the N8VEM SBC board to
allow full monitor capability using the local 7 segment LED displays
and HEX keyboard.  You'll have to check the wiki and/or mailing list
for more details on the DSKY though since I am not really involved
with it.  I have heard they are going to PCB manufacturing order
though so that's a good sign.

I think the ECB bus monitor together with the DSKY would be an almost
unbeatable combination.  I believe Rolf has made his own miniterminal
device similar to the DSKY already and Bernie made a PICE device which
is quite unlike anything I've seen before.  It replaces the CPU and
lets the builder statically test the SBC.  Here is the URL:

http://n8vem-sbc.pbworks.com/f/PICE_Instr.rtf

So depending on what you'd like to do there is probably something for
everyone in the N8VEM project.  I haven't really bothered with front
panel devices since I am more aligned with Allison's approach; use the
RAM monitor and do serial debugging.  It works great and for tough
jobs, use the ECB bus monitor.  Right now I am working on the N8VEM
video display unit which will be a SY6545 video board that behaves
similar to the KayPro 10 video system (once its done).

Thanks and have a nice day!

Andrew Lynch, 73 de N8VEM
0
lynchaj (280)
6/2/2009 9:40:09 PM
 Herbert Johnson
>>  to give up his collection of "ULB's" and scrap them out, it diminishes my
> > hobby, it reduces the value of our interest in them, and it deletes a
> > part of history. That's a loss for all of us.

 MikeS  wrote:

> While I mostly agree with Herb (for a change ;-) I have to also
> partially agree with my namesake:

I agreed with him in part; I'm arguing against his conclusions as
something we *all* should do. (And Mike, by the way, you and I agree
more than we disagree.) But I feel like arguing this out a bit, lay
out a case, get some emotions going. This is a kind of important
point, Mike - is any of this old computer stuff particularly
important, or valuable, beyond what some ya-hoo on eBay will pay
someone for it? Or what some Joe or Jane off the street, thinks about
the stack of boxes and boards one has? Or outside of some dusty museum
exhibit, or obscure Web page?

(If this is too chatty, let me know, and I won't post this way.)

> I think most of us cringe whenever we hear of a "classic" system being
> scrapped, even if it's "just" an "ULB" and doesn't have a front panel.
> But considering the size and weight of these old crates the reality is
> that few people are even willing to pay the ever-increasing shipping
> costs involved, never mind a reasonable price, unless it is a system
> that is visually unique and different from the usual nondescript
> generic boxes.

And yet, these ULB's still get sold on eBay. The shipping cost may be
more than the final bid; but the net amount suggests these ULB's have
a value. As a rough number, it's on the order of $100 net for an empty
ULB. That's more than scrap value. Is it more than scrap plus fuss? -
not for some, not for me, Mike. So, they also get sold as "pickup
only". Just saw an eBay sale like that. Or, it gets traded privately,
some kind of swap. eBay is not the last word on "value".

> So, yes, mea culpa, I've scrapped a number of Cromemco boxes and will
> probably be scrapping a few more...selling a few cards is a lot less
> trouble and nets about the same in the end.

True, as far as that goes. But you can still sell the motherboard,
possibly the power supply, and get more than scrap for them, AND save
on shipping and fuss. If you can get it in a USPS box, you can ship up
to 20 pounds for the cost of about 5 pounds, within the USA.  I agree,
it's a rough "go", I ship stuff myself, I make the same decisions.

Mike, maybe there's a way around this....? Avoiding shipping....?

> Does that really diminishes Herb's hobby, reduce the value of our
> interest in them, and delete a part of history? There are lots of
> other examples out there, in museums, public collections etc, so does
> it really matter in the big picture whether I have a few more in my
> basement or I reduce them to a collection of parts?

Well, it's really not my hobby alone, but that's my point. Telling
people in a public post "it doesn't matter", turns a personal decision
into acceptable general practice. *That* is what I objected to, the "I
give up" quality of the remark. Mike, MikeS, ya' know, these posts get
read by more than you and I. People have a box, they Google around to
see what it's worth. They see posts that say "blah blah blah...ugly
little boxes...scrap scrap scrap." And out on the curb it goes.

Hey, at the 2009 Trenton Computer Fest, I ran into someone who put his
*IMSAI* on the curb, right from his basement. Not years ago, *months*
ago. Just another "ULB" in the trash. The guy groaned when I said
"eBay...thousands..."

But, keeping them in the basement doesn't do much good, either. Many
of us have that problem. Gotta do something with those
boards...scrap?...trade?...trash?...what?

As to Mike S' point about museums, etc: I don't think everything has
been said about S-100 systems. I don't think the museums necessarily
have it right; I don't think the only place for old S-100 systems are
in museums and on shelves in "collections". Do you, really? I say,
make 'em run! Get fingers on the keyboards? Oscilloscopes on the flaky
RAM chips? Get that CP/M prompt on those terminals? Play Adventure?
Hunt the Wumpus? "can I get Internet on CP/M?"

I follow the computer trade press: they describe computer "history",
and what do they say? NONE of these "ULB's" *ever* mattered - except
the Altair was the "first", er, something. But doesn't matter, they
were all "hobby computers", until the real personal computers were
made, by the real computer companies. That's the story, these days,
and "people" just lap that up. Is that satisfactory? Mike (either one)
what does your Web site say about all that? What do YOU say?

Additionally, I say these are still interesting "boxes" to fix,
interesting to run. Even, interesting to add new stuff to - that's
what Andrew Lynch says! Even the S-100 ULB's can stand a new
motherboard, a new breadboard. Can you imagine that? I couldn't. More
than THIRTY years after S-100 systems began in any quantity, you can
get someone's NEW breadboard - for $25 and shipping! And, you can
still get the OLD breadboard, from Vector Electronics, for $45 and
shipping - they TOLD me that!

Kinda interesting, I think. Maybe my neighbor wouldn't be interested.
But he's a jerk. Should we let our neighbors, or ordinary people, or
museums and the computer (Microsuck-up) trade press - all dictate what
is interesting, what is valuable, to you and I? Do we have nothing to
say about these computers, anymore - have the museums and collectors
all have it "said"?

I collect stories *all the time*, from people who have worked, or want
to work, or ARE working, on these systems. Other Web sites do that
too. People do their own stuff, on their own Web sites too.

But there's more. People like my good friend, Dan Roganti. He's
exhibiting old computers, at the Pittsburgh hamfest this weekend.
Imagine that! Listen:

> Just wanted to let you know about the exhibit I'm holding at the
> Breezeshooters Hamfest next month, Sun.Jun.7th. We'll have a bunch of
> early electronics, computers, and video games from the 70's and early
> 80's on display - even some that you can play with. We'll have a bigger
> display than last year with about 25 machines on display.

I'll betcha they have *ugly little boxes* there. I know, because I
sold him some boards for 'em! He made them work!

So, take your ULB. Bring a terminal. Buy a posterboard and write a
description, and when you used it, and what it cost then. Bring it to
a hamfest, or a bake sale, or a trade show, or any other public venue.
See how many people come up to it, talk to you. *Be your own museum*.
Write your *own* history. Write the history that people tell you,
about their experiences. Then tell someone else, put it on the Web.
And get that ugly, little, box running again. Or give it to someone
who CAN.

Herb Johnson
retrotechnology.com




0
herbrjohnson (355)
6/3/2009 2:54:03 AM
Hello, Andrew!

> Hi! =A0Yes, Front Panels are very popular peripherals and they are
> probably the most requested item in N8VEM home brew computer
> project.

I can only repeat that, in my humble opinion, a computer must be
designed, from the ground up, with a front panel. Why use
sophisticated (and expensive) hardware debugging tools, while the
front panel can do a lot of things, without the CPU working! Keep It
Simple Stupid.

> (...) =A0Right now I am working on the N8VEM
> video display unit which will be a SY6545 video board that behaves
> similar to the KayPro 10 video system (once its done).

I had a look to the PDF on your Web site.

In short: drop it. Get or loan one Epson QX-10, and see what it is
capable of doing, thanks to the "NEC uPD7220 Graphics Display
Controller". Seeing is believing. Once you will have seen what it is
capable of doing, you will want to have it on your dream system.

If you re-read those old microcomputer magazines, you will see that
all the last versions of GSX, DR Graph, and DR Draw were made for
micros with the uPD7220. Meaning: the source code already exists!

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/3/2009 6:00:52 AM
On 2009-06-03, Mr Emmanuel Roche, France <roche182@laposte.net> wrote:
> In short: drop it. Get or loan one Epson QX-10, and see what it is
> capable of doing, thanks to the "NEC uPD7220 Graphics Display
> Controller". Seeing is believing. Once you will have seen what it is
> capable of doing, you will want to have it on your dream system.

Good luck finding one.
-- 
roger ivie
rivie@ridgenet.net
0
rivie (670)
6/3/2009 1:52:59 PM
On 2009-06-03, Roger Ivie <rivie@ridgenet.net> wrote:
> On 2009-06-03, Mr Emmanuel Roche, France <roche182@laposte.net> wrote:
>> In short: drop it. Get or loan one Epson QX-10, and see what it is
>> capable of doing, thanks to the "NEC uPD7220 Graphics Display
>> Controller". Seeing is believing. Once you will have seen what it is
>> capable of doing, you will want to have it on your dream system.
>
> Good luck finding one.

Finding a 7220, I meant.
-- 
roger ivie
rivie@ridgenet.net
0
rivie (670)
6/3/2009 1:53:35 PM
Roger Ivie wrote:
> On 2009-06-03, Roger Ivie <rivie@ridgenet.net> wrote:
>> On 2009-06-03, Mr Emmanuel Roche, France <roche182@laposte.net> wrote:
>>> In short: drop it. Get or loan one Epson QX-10, and see what it is
>>> capable of doing, thanks to the "NEC uPD7220 Graphics Display
>>> Controller". Seeing is believing. Once you will have seen what it is
>>> capable of doing, you will want to have it on your dream system.
>> Good luck finding one.
> 
> Finding a 7220, I meant.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390056771718

I've bought from the guy before, he's legit.
0
aek2 (123)
6/3/2009 4:39:57 PM
On 2009-06-03, Al Kossow <aek@spies.com> wrote:
> Roger Ivie wrote:
>> Finding a 7220, I meant.
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390056771718

You'd think by now I'd have learned to keep my mistaken opinions to
myself...
-- 
roger ivie
rivie@ridgenet.net
0
rivie (670)
6/3/2009 7:30:31 PM
Hello, Roger!

> > Good luck finding one.
>
> Finding a 7220, I meant.

I am not an electronician, but I think that NEC produced several
versions, along the years. I am sure that a competent electronician
could find the references of this family of chips.

At a time, this super-chip was generating so much interest that a
small company made it, under the name Intel 82720... I wonder if this
company still exists, and if one could find its manual?

Finally, sorry, but I must point to my own work:

www.cpm.z80.de/roche/NCRGRAF.ASM

will give you a real, practical way of using it.

No need to reinvent the wheel.

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/3/2009 7:31:15 PM
Roger wrote:

> > > Good luck finding one.
>
> > Finding a 7220, I meant.

I have not found one, but then I am not familiar with eletronics
shops.

However, I found something that could interest electronicians:

- "A graphics system design based on the INTEL 82720 graphics display
controller"
   Changon Tsay
   ETD Collection for University of Texas, El Paso, January 1, 1986
   http://digitalcommons.utep.edu/dissertations/AAIEP02441

I am not an electronician, so cannot judge it. I am ready to bet that
there are other similar texts.

> No need to reinvent the wheel.

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/3/2009 9:26:06 PM
Roger wrote:

> > > Good luck finding one.
>
> > Finding a 7220, I meant.

I found something that could interest electronicians:

- "Realization of the Graphics Algorithms on the IBM PC/XT"
   Wookhyun Lee
   Proceedings of the ISL Winter Workshop, February 13-15, 1989

Abstract: The main purpose of this study is to realize a powerful
graphics adaptor on the IBM PC/XT. Some fundamental procedures to
generate lines or circles are stressed. In this study, it is shown
that high-resolution graphics adaptor can be realized at low cost with
graphics coprocessors and additional video RAMs. This graphics adaptor
uses two NEC uPD7220 GDCs (Graphics Display Controller) to increase
the performance. Two coprocessors which are named according to their
functions are a drawing processor and a display processor. The display
processor is the master and the other is the slave. The slave
processor executes RMW (Read-Modify-Write) cycles which generate
graphic pictures. This graphics adaptor needs only 4 ports in I/O
spaces, two ports per processor.

Address of the PDF file, for interested electronicians:

http://icat.snu.ac.kr:3333/ww/pdf/ww_1989_17.pdf

> No need to reinvent the wheel.

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/3/2009 9:45:23 PM
Roger wrote:

> > > Good luck finding one.
>
> > Finding a 7220, I meant.

I found something which could interest electronicians:

- "The Programming of the Intelligent High-Resolution Color Graphics
System NHGCB"
    Huang Fengying Li Guofeng
    Department of Computer Science and Engineering,
    Nanjing University of Aeronautics and Astronautics, 1991

(That is to say: the Chinese University who sent 3 Chineses into
terrestrial orbit.)

Abstract: This paper describes the NHGCB,a high performamce
intelligent color graphics system,which is based on an INTEL 82720
GDC,and has a built-in MCS-51 microcontroller subsystem. It can be
used as an independent graphics system or, together with IBM or other
microcomputer system as a multiprocessor graphics processing system.
The NHGCB can display up to 1,024 by 1,024 pixels with 16 of 4,096
colors. This paper mainly describes the programming of the NHGCB
graphics controller system, which involves the operation (to be
continued...)

http://epub.cnki.net/grid2008/detail.aspx?filename=NJHK1991S1019&dbname=CJFD1991

> No need to reinvent the wheel.

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/3/2009 10:08:10 PM
On Jun 2, 3:13=A0pm, "Tom Lake" <tl...@twcny.rr.com> wrote:
> > So, yes, mea culpa, I've scrapped a number of Cromemco boxes and will
> > probably be scrapping a few more because few people are willing to pay
> > enough to cover shipping and the time, effort and material required at
> > my end; sorry to be crass, but selling a few cards is a lot less
> > trouble and nets about the same in the end...
>
> If you have complete, working systems, please send me a list or post it!
> I'd certainly consider paying for professional packing and shipping.
>
> Tom Lake

Your choice of at least 5 different models; See me off-list:
Delta Mike five six one at torfree period net
(Phonetics and numerals of course)
0
dm561 (120)
6/4/2009 3:03:29 AM
On Jun 2, 10:54=A0pm, Herbert Johnson <herbrjohn...@gmail.com> wrote:
>Mike, by the way, you and I agree more than we disagree.

> Herb Johnson
> retrotechnology.com
------
Of course, Herb! From time to time we've spent a few days pleasantly
arguing over the dancing angel capacity of pinheads, but we certainly
agree on most important issues, and I want to compliment and thank you
once more for the time and effort you've put into your support of the
S-100 and related hard- and software, and the many useful articles and
tips you have and continue to collect and compile on your excellent
site. Kudos!

m

0
dm561 (120)
6/4/2009 3:10:32 AM
On Jun 3, 2:00=A0am, "Mr Emmanuel Roche, France" <roche...@laposte.net>
wrote:
> Hello, Andrew!
>
> > Hi! =A0Yes, Front Panels are very popular peripherals and they are
> > probably the most requested item in N8VEM home brew computer
> > project.
>
> I can only repeat that, in my humble opinion, a computer must be
> designed, from the ground up, with a front panel. Why use
> sophisticated (and expensive) hardware debugging tools, while the
> front panel can do a lot of things, without the CPU working! Keep It
> Simple Stupid.
>
> > (...) =A0Right now I am working on the N8VEM
> > video display unit which will be a SY6545 video board that behaves
> > similar to the KayPro 10 video system (once its done).
>
> I had a look to the PDF on your Web site.
>
> In short: drop it. Get or loan one Epson QX-10, and see what it is
> capable of doing, thanks to the "NEC uPD7220 Graphics Display
> Controller". Seeing is believing. Once you will have seen what it is
> capable of doing, you will want to have it on your dream system.
>
> If you re-read those old microcomputer magazines, you will see that
> all the last versions of GSX, DR Graph, and DR Draw were made for
> micros with the uPD7220. Meaning: the source code already exists!
>
> Yours Sincerely,
> Mr. Emmanuel Roche, France

Hi Emmanuel!  Thanks!  You are certainly welcome to join the N8VEM
home brew computing project and make a video board based on the NEC
uPD7220.  It is clearly a very nice graphics chip and coupled with a
512K SRAM chip would be an incredible device.  Are you aware of any
designs compact enough to fit on a Eurocard ECB PCB?

Upon looking at the NEC 7220 datasheet, I think it is rather
reminiscent of the NEC 765A with its DRQ/DACK interface.  However,
there is no "chip select" pin that I can see -- how strange.  I wonder
if the existing Disk IO "pseudo-DMA" design in the Disk IO board could
be modified for it to work.  It would be an interesting project.

Allison, what are your thoughts on the subject?

Thanks and have a nice day!

Andrew Lynch
0
lynchaj (280)
6/5/2009 12:39:23 AM
Hello, Andrew!

> Hi Emmanuel! =A0Thanks! =A0You are certainly welcome to join the N8VEM
> home brew computing project and make a video board based on the
> NEC uPD7220.

In case you have not yet understood, Andrew, despite publishing more
than 25 programs in the comp.os.cpm Newsgroup, I am only a programmer:
I have no hardware background at all. This is why I reacted so
stringly, when I saw you going into a deadend.

What do you want? Displaying graphics under CP/M? But it has been done
by Digital Research! In addition, it became strategic when WYSIWYG
became adopted by the mob. There are 8-bit and 16-bit versions. For
the 8-bit, there are GSX-80 Version 1.0 and 1.1. For the 16-bit, there
are GSX-86 Version 1.2 (mechanical translation from 8-bit), 1.3, and
1.4. After that, it was renamed GEM and (as far as I know), there were
2 versions.

I had a look to what is available today, and has been available since
Tim Olmstead (that is to say: for years!):

- Screen Driver Documentation
- Color Memory-Mapped Skeleton
- IBM Color Screen Skeleton
- Monochrome Screen Skeleton
- NEC 7220 Screen Skeleton

So, "why re-invent the wheel"?

> =A0It is clearly a very nice graphics chip and coupled
> with a 512K SRAM chip would be an incredible device. =A0Are you
> aware of any designs compact enough to fit on a Eurocard ECB PCB?

Since I am not an electronician, I cannot help. One of my greatest
regreat is not to have convinced Tilmann Reh to use a NEC uPD7220 GDC
for his graphics board for the CPU-280. His's was never finished, he
got married, had kids, then bought a house, etc, etc. With 7220
graphics board, his famous CPU-280 would have been able to run DR
Graph and DR Draw, two *PORTABLE* application graphics programs. I
have used them under CP/M 2.2, CP/M Plus, CP/M-86, and MS-DOS. Find me
a graphical Unix or Windows program able to do this.

Do you want, too, to re-invent business graphics and CAD?

> Upon looking at the NEC 7220 datasheet, I think it is rather
> reminiscent of the NEC 765A with its DRQ/DACK interface. =A0However,
> there is no "chip select" pin that I can see -- how strange.

If I understand well, your remark: The Z-80 and the 7220 each have
their own memory (bigger for the 7220 if it has a color screen. By the
way, in France, there were only *two* known Epson QX-10 with color
screens... And I have one! I had heard, in the Journal of the CP/M
User Group (UK) how good the Epson QX-10 was, so, when I heard that
someone was selling one, I rushed to Paris, and asked to see it
running. The owner inserted a diagnostic disk, and I was in a state of
schock (remember: I started with a NorthStar Horizon, with an ASCII
terminal and a daisy-wheel printer) when I saw those incredibly sharp
letters in 8 colors, then bold, italics, underlined, blinking, etc,
etc! Incredible! If only I had a video of this demo!) and the Z-80
communicates to/from the 7220 using I/O ports. 2 ports are needed
(only). One day, I patched a screen driver (I think it was for the NCR
DecisionMate V) and ran it on my Epson QX-10 after just patching the 2
bytes corresponding to the I/O ports! This was the only change between
2 screen drivers running on different computers! (But both using the
7220) Incredible but true!

> =A0I wonder
> if the existing Disk IO "pseudo-DMA" design in the Disk IO board
> could be modified for it to work. =A0It would be an interesting project.

Everything could be an interesting project, to an hardware type.

However, if your goal is to run plain CP/M 2.2, Digital Research did
it before you, and extended it with CP/NET (network) and GSX
(graphics).

Unless you know more about CP/M than DRI, I suggest re-using what they
did. And they made a lot! (I have not mentioned, for example, Access
Manager and Display Manager, "production application programs" needed
to develop programs for CP/M.) (The GINSTALL of GSX-86 Version 1.4 was
programmed with Display Manager: both programs (like CBASIC Compiler
and PL/I) run under 8-bit and 16-bit versions of CP/M.)

Whew! All those useful programs existing in the CP/M world, and I seem
to be the last one who use it. Sometime, I wonder why some people are
writing in the comp.os.cpm Newsgroup. Most of the American seem
blocked on CP/M 2.2 with ASM and SID, while Digital Research sold
later CP/M Plus with MAC and SID, for example.

Conclusion: Why re-invent the wheel?

Yours Sincerely,
Mr. Emmanuel Roche, France

0
roche182 (635)
6/5/2009 7:43:58 PM
Reply: