VCF East 2025 is April 4-6.
Amiga Roundtables at VCF East Moderated by Dave McMurtrie and Dan Wood.
*Saturday roundtable* includes:
RJ Mical
Dale Luck
Ron Nicholson
Glenn Keller
Andy Finkel
Jeff Porter
Randell Jesup
Peter Cherna
*Sunday Roundtable* includes:
RJ Mical
Dave Haynie
David John Pleasance
Robert Miranda
Hedley Davis
Jeff Bruette
Don Gilbreath
Tickets here:
https://vcfed.org/2025/03/16/non-member-ticket-pricing-vcf-east/
Info here: https://vcfed.org/events/vintage-computer-festival-east/
Many moons ago, I was working at a wind tunnel for aeronautic research.
In the first week, when I started on my job, my future colleagues threw a lot of outdated computer stuff into a large dumpster.
Only many years later, after I became more aware of old computing technology, I realized what that trash was. Duh!
I recently dug through our library and loaned some reports describing the equipment and the software at the time.
Besides several HP 2116, ASR-33, Tektronix 40xx, x-y plotters and more, I also read about their first (pre HP) computer, which was used to control data acquisition and postprocessing.
It was installed in 1966 and replaced by a HP 2116C in 1972.
This was a Pacific Data Systems PDS 1020. It was built into a table and featured an IBM typewriter for printed output and a reader and a punch for papertapes.
One report also contained the "listing" of the program, which is a 4-character hexadecimal dump (with unusual hex digits).
To give you a "feeling" for the code, here is an example subroutine:
0256 L0LS 5001
0258 525S- L0LS M029 CS7D 2260 L0LA M029 CS7D
0260 L011 3002 L0C3- A26M- CS81 3S5A- 7262- 227C
0268 0000 4500 2000 0500- 3000- 4000- 5500-
On bitsavers I found scans of some manuals with the instruction set and encoding.
However, these lack complete programs. Therefore, I have scanned and re-typed the original programs from my report in their original form. Now I am thinking about writing a simple simulator to read and execute these programs.
The PDS 1020 seems to have been a relatively low cost and hence successful computer, but searching the internet I can find only two machines which seem to be in museums. Maybe a few more have survived in personal collections.
#1: https://www.computerhistory.org/collections/catalog/102686768
#2: https://collections.museumsvictoria.com.au/items/397741
Are there more? Are some of them in working order? Is there already a simulator available?
Martin
TEAC FD-55F floppy drives
https://retrocmp.de/fdd/teac/fd55f.htm
The TEAC FD-55F never appeared in the world of IBM compatible computers. Why is that? Because it was simply superfluous in the DOS world.
The TEAC FD-55F is a double-sided 5.25 inch drive that can write 96 tracks per inch (TPI) with 9 sectors per track. In other words, the capacity of a floppy disk is 720 KByte.
There were Radio Shack and other computers (NCR, etc.) that used this format (DSQD).
This corresponds to the capacity of the standard 3.5-inch double-density (DD) drive.
The 3.5-inch floppy disk format was supported since DOS version 3.2.
Introduction of 3.5” drives and disks by IBM (mid-1980s) was one reason why the 5.25 inch drives with 720 KByte storage did not find their way into the IBM world.
==
Further in the above web link:
Changing a Teac FD-55GFR drive to a FD-55F drive ... or,
How do I get my drive to spin at 300 RPM instead of 360 RPM ?
gb
Curious if there's anything in the community on them
They made a cpm based system that was used in HMI control room settings in
the 80's I've got the manuals for their pdm 800 series along with backup of
the software on 8in floppy from the mclelan mine in Lynn lake mb. Love to
find a system the one that went with my stuff got bulldozed into the ground
in 2009
I was wondering if anyone here has experience with the FD55-B with head
load solenoid.
I have a few working ones, but this one is not, and when I look at it,
it differs from the others in that the head "wiggles" up and done on the
side nearest the solenoid.
I can see it is tight on the rail oppose the solenoid, but on the side
nearest, the back of the head does not connect with the rail on the back
(which seems correct, as there is a piece of that extends out and looks
to slot into a sensor.
But, I'd assume the front mount would hug the rail, but it only does on
the top.
By pushing the head close to the disk in use, I can get it to work, so I
think this loose head issue is the only one.
I guess:
* Anyone seen something like this?
* Is this a broken rail mount on the head, or something else?
* If its broken and probably can't be fixed, anyone have a parts FD55-B?
* Can one replace the head on these (it looks like you can, but I admit
I have never changed parts in a drive mech.
Jim
--
Jim Brain
brain(a)jbrain.com
www.jbrain.com
VCF East has a food truck this year! Boardwalk Bites agreed to have a truck
there.
Besides the long lines at Consignment, on-campus food had the biggest
complaints from last year's survey. We hope that this solves this problem.
MENU:
BREAKFAST (Served from 7:30 am)
Pork, Egg and Cheese Roll
Egg, Bacon and Cheese Burrito
Bagels and Pastries
Coffee & Tea
LUNCH (Served from 11:30 am – 2:00 pm)
Cheeseburger
Sausage & Peppers Sandwich
Vegetarian Sandwich
Cheesesteak
Seasoned Fries
Fresh Fruit
BEVERAGES
Water, Soda
Show info: https://vcfed.org/events/vintage-computer-festival-east/
Tickets: https://vcfed.org/vcf-east-tickets/
Brian Kernighan will be interviewed by Stephen Edwards about his 2019 book:
UNIX: A History and a Memoir. He will be there Saturday, April 5 at 5PM.
Brian Kernighan worked at Bell Labs and co-wrote the first book on C
Programming (in 1978) with Dennis Ritchie: "The C Programming Language"
VCF East 2025 will be in Wall, NJ from April 4-6.
More information: https://vcfed.org/events/vintage-computer-festival-east/
Tickets: https://vcfed.org/vcf-east-tickets/
Take care!
Jeff Brace
VCF East Showrunner
I have some 3.5" PATA drives. One WD2500 250 GB drive and two Maxtor
Max Line II 320 GB drives. All three passed SMART long tests.
If you need any, they're yours for the price of a PDF shipping label.
Hi, located in Eastern MA, I already have a couple of interests, but
I'll see what comes in. Multiple q-bus boards that can easily ship, a
VT103, a BA chassis 9x4 I think and two RX02 units.
