On Mar 12, 22:01, Doug Yowza wrote:
> Speaking of IMSAI's, I just bought a PROM/RAM board from somebody (it's on
> its way) without knowing exactly what it is (that's my standard MO). All
> I know is that it's a Vector Graphics board for an IMSAI (and comes with
> the original receipt from IMS, as well as an original IMSAI catalog!) and
> I can tell from Bill R's Tandy catalog
> (http://incolor.inetnebr.com/bill_r/Tandy_TOC_Frames_Page.htm)
> that it was intended as a front-panel replacement (are your fingers red
> and swolen?).
>
> My guess is that a PROM/RAM board is sort of a ROM emulator. Am I close,
> or is it just a board that can handle PROMs and RAMs?
I'd expect it's just a board that can hold either PROMs or static RAM. A "ROM
emulator" usually refers to some plug-in device, often controlled by a logic
analyser or EPROM programmer with a ribbon cable, that pretends to be a ROM.
Used for development purposes: instead of switching the machine off, counting
to 15, pulling the EPROM, blowing another, fitting it, straightening the pins,
fitting it again, powerering up... you can modify the code on the fly (or while
the machine is halted).
Do you mean it's a board that can do vector graphics, or that it was made by
"Vector Graphics"? I assume the latter, as the former doesn't fit with the
rest of your description. A "front panel replacement" usually means a
ROM/PROM/EPROM board with bootstrap and perhaps monitor code, so you could type
simple commands and get a (textual) response on a VDU instead of having to
toggle the switches and watch the blinkenlights. Quite often, ROM boards could
be could be jumpered for different addresses, not just a bootstrap address, and
sometimes they could hold byte-wide static RAM instead of byte-wide EPROM.
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
That NY Times article that Charles Fox mentioned requires a username and
password to access. Charles, could you pull that from the web site and
post it here for all to see?
Sam Alternate e-mail: dastar(a)siconic.com
-------------------------------------------------------------------------------
Computer Historian, Programmer, Musician, Philosopher, Athlete, Writer, Jackass
Coming Soon...Vintage Computer Festival 2.0
See http://www.siconic.com/vcf for details!
(Another cheap way to start a dumb thread)
I came across a thread on a newsgroup about IBM naming schemes, and was
wondering about all of the Systems/ and Series/. This is what I could come
up with for the hardware...
S/1, PS/1, PS/2, S/3, S/4,
S/23, S/32, S/34, S/36, S/38, S/88,
S/360, S/370, S/390, AS/400,
RS/6000, ES/9000
Are there any I missed?
William Donzelli
william(a)ans.net
Ok...here's the problem
The machine come up with garbage on the screen.It would also seem that the
video is inverted, I can see the retrace lines etc, so the horizontal
blanking is not working either by the looks of it.
What I suspect is wrong is that either U42 (the 6845 labeled in my machine
as a motorola SC80757P) or U102 (the 4.3 video support chip) is faulty (or
both?).
Does anyone have any info on U102 (what is it..can I get another?) or any
other thoughts.
Some other notes are.
1. It seems to boot (I get a very crappy tandy logo in inverse on the
screen) though the screen is so unstable as to be unreadable.
2. It does not matter if it is in 64 or 80 column mode, the video is still
crap.
3. I suppose the Char generator rom could also be a problem
Any help would be appreciated. BTW does anyone have the diagnostic disc for
the 4/4P ?
Cheers
+----------- Keith Whitehead -----------+
| Physics and Chemistry Depts |
| Massey University |
| Palmerston North |
| New Zealand |
| |
| Ph +64 6 350-5074 Fax +64 6 354-0207 |
+------------------------------------------+
I have a Z80 computer that I built from a kit in 1978 and I hate to just
set it on the curb and scrap it. It was designed and sold by 'the digital
group' of Denver, CO. It has a Z80 8 bit microprocessor, 2.5 mh, 64K
memory, 80 X 24 output to a monitor, dual 8" floppy drives added later from
Bell Controls of CA and a CPM operating system.
Components:
1 Cabinet containing processor board, memory boards, disk I/O boards, TV
output board and power supply.
2 Keyboard
3 Dual 8" floppy disk drive
4 19" monitor for output
5 Modem
6 Documentation
I would like to donate it. Interested?
Ron Slonneger
Peoria, IL
>anything that a turing machine can't prove is unprovable. kurt godel
I'm reading Douglas Hofstadter's Godel, Escher, Bach, which is about
information, patterns, number theory, intelligence, and so on. I
implore everyone to read it, it is something any scientist ought to be
familiar with like the three laws of motion. Copyright 1979,
ISBN 0-394-74502-7. He wrote some more books after this one, but this
one is better. Two others I have read deal with the same thing.
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
Can someone tell me what this thing is? It was a freebie (a appearnlty
rightly so). It's got a genuine MC68000P12 in it. When I plug the video
in and turn it on, it just sits at a blank screen with a flashing cursor
in the corner.
I've gathered that it's somesort of graphics workstation but I know
nothing more.
Thanks,
Adam
----------
Adam Fritzler
afritz(a)iname.com
http://www.afritz.base.org
----------
>Instead, Q is low and NOT Q is high which is the reverse of
what SHOULD
>be the case. What's the deal? Bad 7474? Or is my thinking
SCREWED UP?
>
>IF my thinking is correct and my suspicion that the 7474 is
bad, is it
>safe to replace it with a 74LS74? A friend of mine and I had a
long
>conversation about what you can replace with what and I've
forgotten
>what he told me about that.
>
considering the low speed of a 6800, an LS (or even an HCT)
should work...but, are you sure it isn't the case of a fast
pulse on the D input when CLK is hit (on the falling edge if
memory is correct)? and you aren't seeing it (using a logic
probe or a triggered scope)? did you check the voltage in to D?
maybe it's in no mans land (i.e. around 2v). Maybe its the IC
driving the flip flop D input thats bad, or a fast pulse is
hitting the R* input
Anyway, I'd take it out and put in a socket if you think its
most likely cause
Jack Peacock
Just in case you're interested, I've set up a sharp MZ-80K oriented site
(below).
If you have any information which may be suitable for inclusion, please let
me know.
Thanks
--
Mike
http://www.boink.demon.co.uk/sharp/
