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I > IMLAC > PDS-1   


The Imlac PDS-1 is a graphical minicomputer made by Imlac Corporation (founded in 1968) of Needham, Massachusetts. The PDS-1 debuted in 1970 and is considered to be the predecessor of all later graphical minicomputers and modern computer workstations. The PDS-1 had a built-in display list processor and 4096 16-bit words of core RAM. The PDS-1 used a vector display processor for displaying vector graphics as opposed to the raster graphics of modern computer displays. The PDS-1 was often used with another flagship Imlac product, a typesetting program called CES.

The PDS-1 was used in many pioneering computer applications. The FRESS hypertext system had enhanced capability and usability if accessed from a PDS-1 system; the user could make hyperlinks with a light pen and create them simply with a couple of keystrokes. Multi-window editing on FRESS was also possible when using the PDS-1.

The PDS-1 also had the capability to run remote graphical programs such as those that ran on the Stanford AI Lab's main computer. The PDS-1 was also able to run Mazewar, the first online multiplayer computer game. The PDS-1 connected to a host PDP-10 computer (located at MIT) running ITS over Arpanet and the Mazewar program. Up to 8 players running PDS-1 minicomputers or other terminals could access MIT's Mazewar host. The PDS-1 was also important during the early days of Arpanet when network graphics protocols were under consideration.

Source: Wikipedia

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I used to work at Imlac in Needham, MA back in 1975. I was an electronic assembler/tester and built the CRT monitors and light pens. I remember getting a -1450 volt shock from a defective light pen! We used to make 100 foot cables by pulling the wire bundles through a shrink wrap tube. We used talcum powder to help get the cables pulled through!

Saturday 23rd April 2011
Gary Paresky (Massachusetts/USA)

I used the Harvey Mudd College PDS-1 from 1973-1977 - I was the main user of it as I was on it all the time when I should have been studying math. Wrote, for a professor, a program to allow building pictures of Maya glyphs - dragging them from a menu to a nested grid with the light pen (then printing them for his publications.)

CPU instruction set was a "stretched" PDP-8 - stretched from 12-bit to 16-bit, a B accumulator added to the A accumulator, and more post- and new pre-indirect-increment addresses.

"GPU" shared cycles with the CPU - only one or the other ran - and had an instruction set that looked like a "display list". So I wrote an implementation of the brand new SIGGRAPH Core Graphics System for it.

Got me my first job out of HMC too! Went to work in 1976 for Honeywell Marine Systems Division which was delivering the PDS-1 as the instructor''s console in a multi-computer multi-student Navy sonar training facility. Wrote the program that drove the console - the teacher would set up ships with their speeds and routes and other ocean noises (whales, etc.) - as a scenario for the students to work.

Monday 14th October 2019
David Bakin (USA)
Bakin''s Bits

In 1972 I was assigned to develop a process to proofread text destined for composition on a Photon 713. This was a phototypesetting process that used Friden keyboards producing paper tape from manuscript. The PDS1 system was to be used to proofread text without first running the tape on the Photon 713 projected onto photosensitive film. Our PDS1 system consisted of the display, keyboard, additional keyboard, AB Dick printer with embedded 7" flat faced monitor projecting text to electrostatic paper and paper tape reader/writer. We designed 1,300 unique characters to match shape and spacing of Times Roman medium, italic, bold and bold italic font as well as the 4 faces of the Univers Medium font. The process was a complete success except for the inability of the AB Dick copier to keep the toner solution fully mixed. The system was the equivalent of desktop displays currently available back in ''72.

Saturday 3rd June 2017
Bob Rasmussen (Maryland, United States)


TYPE  Professional Computer
YEAR  1970
KEYBOARD  Full-stroke keyboard
CPU  Unknown
SPEED  Unknown
RAM  4096 16-bit words
VRAM  Unknown
ROM  Unknown
GRAPHIC MODES  vector display
COLORS  green and black
SOUND  Unknown
SIZE / WEIGHT  Unknown
I/O PORTS  Unknown
OS  Unknown
PRICE  Unknown

Software for this system!

1973 company unknown

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Ready prompt
ZX Spectrum
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C64 maze generator
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Commodore 64 prompt
Pak Pak Monster
Pixel Deer
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Shooting gallery
3D Cubes
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Vector ship

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