Hi,
I found this in a pile of surplus computers yesterday. Can anyone tell
me what it is? It looks like an ordinary external 5 1/4" drive box but on
the back of the box it has a DB-25M connector marked "MODEM/CPU" and a
DB-25F connector marked "TERMINAL". There's also a rotary switch labeled
"RATE" with positions marked "10", "30", "120", "240", "480", 960" and
"EXT". Then there's a toggle switch with positions marked "BIN CTRL ON"
"ODD" and "EVEN". And another toggle switch with positons marked "FULL" and
"HALF". It has a socket for a standard AC line cord. It's made by Techtran
Industries of Rochester, N.Y. and it's a model 950A. My guess is that it's
a disk drive that's made to go between a terminal and it's MODEM or
computer but I've never heard of one before. If that's what it is, then
how do you give it coomands?
Joe
Hi,
I have a number of Mac base units, Apple Trinitron monitors and external
SCSI 44MB & 88MB SyQuest drives for sale. I hope the prices are reasonable;
they should be worth it for the parts value alone (memory, floppy drives,
case, video card, PSU, CPU).
Most of the Mac stuff is around 10 years old.
Unless stated, everything is tested working and can be seen working.
Collection from Dorchester, Dorset, England would be preferable.
Also, would there be any interest in Digital VT420 terminals, maybe other
types of DEC terminal too? I may be able to acquire a quantity of these very
cheaply. I'm no DEC expert; does a complete terminal consist only of the
monitor and keyboard?
Mac base units
--------------
None of these have hard disks. Would be good for upgrading an existing Mac
setup.
Mac II. Has 800K floppy drive, 20MB RAM (four
1MB and four 4MB 30-pin SIMMs). 68851 MMU
chip fitted. Has NuBus video card made by
Apple (FCC ID of video card is BCG9GRM0201). 20 pounds
Mac II. Two floppy drives, one 800K other
1.44MB. No RAM or video card. 10 pounds
Mac II. 8MB RAM. two floppy drives, one 800K
other 1.44MB. Has Megascreen 2001 NuBus video
card by Megagraphics (may be able to output
NTSC/PAL video according to text on PCB).
The 800K floppy drive may need cleaning. 15 pounds
Mac II. High density floppy drive. No RAM or
video card. Probable PSU or main board fault;
unit shuts down when a floppy disk is inserted.
Floppy drive is good. 4 pounds
Mac IIx. Two 1.44MB floppy drives. Has 16Mhz
68030, 68882. 8MB RAM, NuBus video card.
Second floppy drive may be unreliable. 20 pounds
Mac IIci. High density floppy drive, no RAM.
Has 25MHz 68030, 68882. 15 pounds
Mac IIvi. Has 16MHz 68030, unsure of amount
of RAM on board. High density floppy drive. 15 pounds
Mac IIvx. Has 33MHz 68030, unsure of amount
of RAM on board. Contains Apple NuBus video
card with 1MB RAM (FCC ID of this card is
BCGM0121) 20 pounds
Mac Centris 650 w/ 44MB SyQuest drive. Has
68040 CPU, unsure of amount of RAM on board.
High density floppy drive. 30 pounds
Power Mac 6100/60. 16MB RAM (I think). Has
Apple PC emulator card with 486DX266 CPU and
additional 8MB RAM (FCC ID of this is
BCGM3581). High density floppy drive. Unable to
fully test due to not having correct monitor
cable, but unit makes normal "bong" sound when
powered up. 35 pounds
12" Trinitron monitors
----------------------
Macintosh Color Display (M1212) 20 pounds
Macintosh Color Display (M1212) 20 pounds
AppleColor High_resolution RGB Monitor (M0401Z) 20 pounds
External SCSI SyQuest drives
----------------------------
I have tested all these to the extent of powering up, drives are visible on
SCSI bus. However I do not have any SyQuest media to fully test. Will offer
DOA warranty. These are probably worth it for the cases alone.
Mass Microsystems DataPak 44MB drive 10 pounds
Mass Microsystems DataPak 88MB drive 15 pounds
Computex 44MB drive 10 pounds
d2 88MB drive 15 pounds
Micronet 44MB drive. Case damaged, drive
probably okay 4 pounds
External SCSI cases
-------------------
Case from Apple Hard Disk 40SC, no drive FREE with other purchase
Case from Apple Hard Disk 20SC, no drive FREE with other purchase
-- Mark
Using ASCII line art and a printer for plotting allows the human brain to
see patterns in large amounts of data. If I plot 3,000 points using a pen
plotter with 6 points to the inch I would end up with 40 feet of plot paper
with a fine wiggle line on it. If I used a printer, the paper was cheaper,
the plot was cruder, but your brain doesn't get lost in the fine detail but
sees an overall pattern. If you look at 100's of plots, the overall pattern
will become clear. This may be analogous to looking at a highway versus a
string to see the trend in points of data.
All of a sudden I just realize that if you looked at enough data maybe your
brain spontaneously creates patterns. Occasionally I looked at data after
consuming a "few" beers, there was lots of patterns then.
OT: OT:
Have you ever punched cards after a few beers? I seem to remember finding
occasional duplicate lines of code or code of the form:
100 IF(I) 100,100,100
you may recognize FORTRAN II.
Mike
"more patterns than brains"
As a matter of fact and in light of previous exploits on YOUR part yes we do
expect you to remember it. If it was anyone else we wouldn't even bother to
ask;)
Francois
>>
>> > A maths book we used at school had a paper tape strip as part of the
>> > picture on the cover, and that _did_ make sense when read as 5-level
>>
>> What did it say?
>
>Look, this was 20+ years ago, and I no longer have the book :-). Since
>then I've seen _hundreds_ of pieces of paper tape, and had to read a
>number of them by hand. You expect me to _remember_ one of them ??? :-)
>
>-tony
There was "actual" work done using ascii art. We used to plot growth curves
of bacteria using ASCII characters. We looked at the growth patterns of
1000's of samples with varying concentrations of antibiotics included. This
was very cumbersome and slow. We then purchased a Versatec printer to speed
the process. Still ASCII plots but faster. One research run would consume
an entire box of versatec paper. For recreation I developed a raster
plotting version on the Versatec but it was much slower and computer
intensive, it did do b/w pictures nicely. The next refinement after plain
ASCII printer art was output on a Printronix P300 or P600. You could print
raster pictures. The sound of the printer tipped off the staff to the
production of a picture. Afterhours was always available.
I may try and read my old tape and recover the images. I know it was
scanned using a vidicon tube over a light box at 256 X 256 resolution 8 bits
grayscale. I have kept and moved the tape for the last 25 years.
Mike
"Old computer guy"
Richard:
>available and more used in the U.S. than anywhere else. Consequently the
>techniques spread. I doubt programming will ever be freed from the mantle
>of "mystical art" or "right-brain activity" long enough to allow the
>introduction of discipline. I'm beginning to believe that programming is
>more a disease than an engineering discipline. It seems more folks get
into
>it indirectly and almost against their own wishes. Thank goodness that
they
>stick with it long enough to generate the tools we all use and love to
hate.
This is a good point. I write code, lots of it. I'm a hardware person so
I'm
one of those that really do not see myself as programmer save for I'm forced
to! Also while I do see hardware as art (right brain) programming for me is
mostly mechanical/procedural and IDEs drive me nuts for that reason.
On the other hand, in the last 10 years there have been more lines of code
generated the likely the preceeding 20 years and so on. The need to solve
problems does force this forward.
SEANS copy:
>> The project he's on is a complete disaster as the manager went for a
>> Microsoft solution using slews of programs communicating via COM,
>> DCOM, OLE and other alphabet soup of Microsoft technology. A year
>> later and it still doesn't work and my friend has basically told the
>> manager it has to be scrapped and done from scratch, preferably
>> using something other than Microsoft (although my friend might have
>> a slight bias).
Richard:
BTW, your apparent juxtaposition of one word for its homomymn, and it
>happens all too often with this particular one. There's this term,
>pronounced "sloo" which is often misspelled "slew" but which should be
>"slough" also pronounced "sloo" meaning a swamp or quagmire.
To me fyi, SLEW is my word of choice for things that have a delta, IE:
any moving target. MS interfaces are clearly slewed over time.
While it must bother some as misuse, I read it as both usages as
one rather funny pun. It is a quagmire and also there are a rather large
collection of goo all adhering to the mess called Windows. Got any Windex?
The idea of a windowing system, thank xerox parc for that, apple and MS
put it in front of people when hardware to run it got reasonable, it was a
hit.
historically "windowing" was the killer idea just like visicalc and easy to
use databases (dbase) that needed to happen to get a lot of computers
on more than desks of computer savy people.
Allison
I stopped by one of my favorites scrap yards yesterday and found SIX
Cromemco Z2D S-100 bus computers. They were getting ready to shove them
into a container of scrap that was heading for China. These a nicely loaded
copmputers that have two floppy drives and a hard drive. They were mounted
in 19 inch racks and were used to operate some kind of test stations and
were in perfect condition. I managed to get one more or less complete one
and most of the cards out of the others but they wanted the racks to appear
full so that won't let me have any of the other cases, power supplies or
drives. I watched as one was smashed to half it's original size trying to
make it fit in the shipping container and another was torn to shreds (20
pound computer vs 12,000 pound forklift). I substituted DEC stuff in the
shipping container for the last three so they have a short reprieve. I
think I've made a deal to swap some other rack mount stuff for the
remaining cases and parts. (Keeping my fingers crossed!)
I also found three TRS model 4s there. These just came in yesterday and
should be safe until Saturday since the owner's are out of town till then.
They appear to be complete and in good shape but have been in storage for a
LONG time and are dirty and dusty. That's all I know about them. If anyone
is in the central Florida area and wants one or all of the model 4s and can
pick it up Saturday, contact me directly for directions.
Joe
I guess I must be an old school type of programmer. About 1975 each student
seemed to have a program they developed. I used a Fortran program that had 3
arrays each 10 characters deep. You scaled the picture value into the range
0-9 and used the value as an offset into the array. You printed the line 3
time with out a line feed and then issued a line feed.
Example:
picture value array 1 array2 array3
0 space space space
1 period space space
2 colon space space
3 plus space space
.
.
.
9 0 W M
With this scheme you could build up a fairly dark spot for black points.
Later versions included image processing to improve the look of the image.
Histogram equalization makes visually much better pictures. Early weather
maps are a good example of this type of image. I remember seeing punch card
decks that had ASCII pictures in comments at the beginning. It made it easy
to see if your output was coming off the printer when you saw the picture in
the source.
Mike
"old code dog"
The good news is that I took apart my VLC, pulled out the two EPROMs
holding the firmware and successfully read them out and saved them to a
file on disk.
The bad news is that the EPROMs are 27210's (64K X 16 bit) parts.
Apparently these weren't popular enough to either make it into the
"mainstream" or into over stock :-(.
Digi-key, Mouser, JameCo, Future-Active, Wyle, all came up empty. JDR's web
site claimed they had them but the order failed and said "call customer
service" :-0.
So there you go, a "valuable" IC for those with VLC's.
--Chuck
They always said that you learn something new every day.
Thanks for the dual-ported tutorial.
Rich
==========================
Richard A. Cini, Jr.
Congress Financial Corporation
1133 Avenue of the Americas
30th Floor
New York, NY 10036
(212) 545-4402
(212) 840-6259 (facsimile)
-----Original Message-----
From: Eric Smith [mailto:eric@brouhaha.com]
Sent: Tuesday, May 23, 2000 5:45 PM
To: classiccmp(a)classiccmp.org
Subject: Re: Altair parts substitutions
> This is what I meant exactly - no bi-directional data bus. I'm guessing
that
> there is a fine distinction between dual-ported and separate input and
> output busses...
Specifically, a true dual-ported RAM chip has separate address busses and
control signals/strobes (*RD and *WR, or *CS and R/*W, or the like) for
each port.
Dual-port RAM chips tend to be expensive and not very high-density, so
they aren't commonly found in commodity computer hardware. It's usually
more cost-effective to time-multiplex a single port.
Current manufacturers of dual-port RAM chips include Cypress and IDT.
There are even some quad-port RAM chips now.
