>>Do you need me to give you a copy of anything? My calendar program
>>actually reads compressed versions of the picture files, since our system
>>ran from RK05 disks (2.5 megabytes) back in the 1970s. The version of
>>the program that I have was developed at Wofford College around 1976
>>and was based on another calendar program.
>
>Hmmm, wonder if it's Y2K-compliant? :)
Surprisingly, I think the answer is YES.
Actually, I seem to recall that our version would print calendars into the
21st century and beyond. I remember using the same calendar / day of week
routines to do a computer programming assignment that calculated the
date of Easter from the years 1500 to 2500.
We did not use the built-in date functions of RSTS and Basic-Plus.
I'll have to take a look at the code to verify this.
Ashley
> What program would have made this calendar and is one still
> available, somewhere, that I could run on Windows or through something like
> SIMH?
>
> Rich
I have a program on my PDP-11/40 that will print these calendars. This
program is from around 1977-78 and is written in Basic-Plus. I'll have to
check to see which pictures I have on my system. I have printed several,
including Snoopy, the USS Starship Enterprise, and a couple more. They
print ok on my LA120 DecWriter III or LA36 DecWriter II as long as I
have a fresh ribbon on the DecWriters.
Do you need me to give you a copy of anything? My calendar program
actually reads compressed versions of the picture files, since our system
ran from RK05 disks (2.5 megabytes) back in the 1970s. The version of
the program that I have was developed at Wofford College around 1976
and was based on another calendar program.
Thanks,
Ashley
I know aperture cards have a long life.
In one of my previous work lives, 1973-1975, I copied X-ray film from
14" X 17" film to aperture cards. They were the size of computer punch
cards and had a line of text typed along the top. There was a 1" X 1"
film embedded in the card. We were the beta test site for Kodak for a
medical image archive based on them. Retnar was the product name I
think. I tried scanning them with a Vidicon camera attached to the
bioengineering lab's PDP-11/20. The camera was only 256 X 256 by 8 bits
per pixel, not enough resolution to recover an image. The display on
the system was a RAMTEK display with 256 X 256 by 8 bits, 3 bits red, 3
bits green and 2 bits blue. I think the display system was about $50K.
I still have some intact 30 years later.
I am also scanning old family slides that are at least 40 years old. I
think the storage conditions are the key to good longevity of film.
Cool and dry is essential.
I'm partial to film. My family has 16mm and 8mm film originals of
family events from the last 40 years, copies on VHS tape and copies on
VCD. The magnetic tape is beginning to fade. The VCD's are copies of
the VHS version. The film is a pain to thread into the projector but
it's still great quality.
I've heard that pen on paper is very good because the ink is
embedded/absorbed into the paper. This is unlike a laser printer where
the plastic toner is melted onto the surface of the paper. Maybe an
archival quality ink on a pen plotter on vellum is what you want. I
think that's what the local plat and land documents are created on.
Mike
I am trying to figure out the voltages on my PDP-8/A (Omnibus)
logic lines. DEC's documentation, as usual, is confusing at best
on this (and other) subjects, and sometimes apparently
self-contradictory...
DEC used suffixes -L and -H to mean active-low and -high
respectively (that is, a logical assertion). They also say when
interfacing to the Omnibus that standard TTL levels are used. But
elsewhere in the manual it says Logic 1 levels are near 0 volts
and logic 0 is near 5 volts! So does this statement apply only to
the bus signals that are already active-low?
Am I correct or not in interpreting, for example, an address line
named "MA 11 L" to be a logic 1/true/asserted when 0-0.8 volts and
logic 0/false when 2.0+ volts (TTL levels)?
thanks for any assistance.
-Charles
>
>Subject: Re: Fwd: questions about Sanyo MBC 55x collectors
> From: Chris M <chrism3667 at yahoo.com>
> Date: Mon, 10 Oct 2005 12:25:37 -0700 (PDT)
> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
>
>> The Sanyo ran at 3.58MHz (8088)
>> so that they could use
>> CHEAP color burst crsytals for the oscillator.
>
> Almost all the pc's used a crystal that was some
>multiple of color burst frequency. Did the Sanyo
>actually use a 3.58mhz crystal? The PC had a crystal
>that was 4x that, and divided it by 3 to get 4.77mhz.
the IBM PC used the 8284A clock generator to pump the
8088 and that chip generates the 30% duty cycle required
by dividing a higher frequency (14.31818mhz) to 4.77mhz.
That higher frequency was high enough for Video clock
generation as well.
The IBM PC also another osc for the baud rate clocks
and the Video had it's own clock.
Many other machines used 3.58 (3.57545mhz) as it was easy
to find and cheap, almost 4mhz and related to US video
color burst. However the primary reason it was cheap
crystal. In some cases the cpu was also limited to 4mhz
or lower and that factored into the clock used.
Allison
At 20:16 09/10/2005 -0500, you wrote:
>Dave Dunfield wrote:
>> - Run ImageDisk, select the drive etc. and execute the A)lign/Test function.
>
>Sadly, the drive is so far off that I can't get the thing to boot at all to run
>ImageDisk :-( But thanks for the instructions; I will clip'n'save them.
Actually, it never occured to me that anyone would try to do this by booting
>from the drive. I was thinking that you would pull the drive and drop it onto
a working system.
One thing I have on my bench which is very handy, is the PC has modified drive
cable which brings drive 'B' out to a 37-pin 'D' connector on the back, and
a plug-in cable to allow me to easily connect external drives. I use this both
for testing drives, and for imaging from/to 5.25" and 8" drives.
I have details/photos on how to make the cables and adapters posted to my site.
Look at "Disks/Software images" near the bottom, and then "notes on connecting
an 8" drive.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
As the subject implies, I've got a PCjr with a floppy drive that is having
trouble reading disks and fails the internal CTRL-ALT-INS diagnostics.
Symptoms include a very loud/bad noise at first seek (rest of seeks sound ok),
and a "B" ("have drive serviced") result of the diags. The diskette I used for
diags was tested in a 5150 and found to be good. This drive was working a week
ago but has declined steadily until it can't successfully boot the machine. (I
bought some time by formatting disks 8 sectors per track instead of 9, but that
no longers works :-) I've already cleaned it using a cleaning diskette and
alcohol.
What are my options? Is the floppy drive in a PCjr as goofy/proprietary as the
rest of the machine? If so, should I even attempt to repair it? By the bad
clunk/buzz noise, I am assuming the head is slamming into the side of the drive
or something equally heinous.
Another related question: When I was first getting started with personal
computers 25 years ago, I seem to recall that track alignment was a common
problem and could be fixed by using a calibration diskette and special software
that you could monitor as you turned the alignment screw. Without one of those
factory calibration diskettes, is it even possible to align/calibrate a floppy
drive for track alignment?
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Want to help an ambitious games project? http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
> Hi, I'm new to the list, but not new to classic computers.
> I picked up a rare beast (Apparently) years ago when I bought a System
> 23 tower system at a thrift shop years ago, and it's been
> sitting in my basement for a few years after a rough life in
> makeshift storage. I want to see if I can get this thing
> cleaned up and running
I just picked up a set of manuals for one. The same person
has a system, and software also.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5812578529
>A disk drive performs several different functions. In particular, it
>rotates the disk, it detects the index hole and write protect notch, it
>moves the heads between cylinders and detects the track0 position, and it
>actually does the reading and writing.
This much I actually know :-)
>Do you know which, if any, of these systems are working? Can you get the
>disk to spin? Do you get an index pulse? Can you get the head to move?
>And so on.
All functions appear to work (Motor, Index, Step) - problem in all cases
is in the read/write circuitry. Drive goes through all the motions, it
just can't read/write.
>A drive exerciser is handy for this, but by no means essential.
Imagedisk's "Align/Test" function lets me excercise the drive with a fair
bit of manual control.
>You can
>often get away with just pulling pins on the interface connector low with
>bits of wire connected to the 0V line. And look at the outputs with a
>logic probe. Remembr there output drivers are open-collector, so you need
>to add terminating/pullup resistors (traditionally 150 ohms to +5V) for
>tssting.
>
>Note that some drives with a big ASIC or microcontroller on them do some
>kind of power-on initialisation. In particular, a few drives do odd
>things if inputs are held active (low) at power-on. Other drives will
>ignore all inputs if the power-on seek-to-track-0 fails.
>
>If you have one of the latter units, you should be able to see
>transitions on the stepper motor drive outputs just after power-on. And
>you can check the track0 sensor by hand, of course.
All of this works.
>I can't believe it would be that hard to trace out a schematic. Even if
>there's a big ASIC in the middle of the board (likely on half-height
>drives), you can often figure out what it's doing from the surrounding
>circuitry. You can at least check if things like senosr inputs do the
>right things as you move a bit of card in and out of the sensor, etc.
It may come to this - At least I do have a couple of working drives
that I can compare signals with - but I asked in case a) someone has
the technical documentation or b) someone might say "oh yeah, thats
a common problem caused by xxx...", either of which could save me a
lot of time.
I think I agree with Allison however that these drives are crap, and
I'm not sure I want to spend a lot of time on them if suitable
substitutes can be found - in this case, the physical constraints make
this a but more challenging.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
