IMLAC PDS-1 - Revision history

Jnc: /* External links */ Good caption for link; add front panel image

2025-06-27T21:51:47Z

External links: Good caption for link; add front panel image

← Older revision		Revision as of 21:51, 27 June 2025
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	** [http://www.bitsavers.org/pdf/imlac/PDS-1_TechnicalMan.pdf IMLAC PDS-1 Programmable Display System Preliminary Technical and Operator Manual]		** [http://www.bitsavers.org/pdf/imlac/PDS-1_TechnicalMan.pdf IMLAC PDS-1 Programmable Display System Preliminary Technical and Operator Manual]
	** [http://www.bitsavers.org/pdf/imlac/PDS-1D_ProgrammingGuide.pdf IMLAC PDS-1D Programming Guide] <!-- also http://www.ubanproductions.com/ImlacDocs/PDS-1D_ProgrammingGuide.pdf -->		** [http://www.bitsavers.org/pdf/imlac/PDS-1D_ProgrammingGuide.pdf IMLAC PDS-1D Programming Guide] <!-- also http://www.ubanproductions.com/ImlacDocs/PDS-1D_ProgrammingGuide.pdf -->
	* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]		* [http://www.ubanproductions.com/imlac.html Imlac Anatomy] - large collection of very good images of a PDS-1D; details of getting Maze War running at the 2004 7th annual West Coast Vintage Computer Festival
	** [http://www.ubanproductions.com/imlac_sw.html Imlac Software Library] - includes many IMLAC documents, not all of which are at Bitsavers (above)		** [http://www.ubanproductions.com/imlac_sw.html Imlac Software Library] - includes many IMLAC documents, not all of which are at Bitsavers (above)
			** [http://www.ubanproductions.com/Images/imlac2.jpg The programmer's console] - large image of the front panel
	* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]		* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]
	* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/Screen%20Addressing%20in%20FREEWAY%20(1971)%20for%20the%20IMLAC%20PDS-1.pdf Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1]		* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/Screen%20Addressing%20in%20FREEWAY%20(1971)%20for%20the%20IMLAC%20PDS-1.pdf Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1]

	[[Category: Workstations]]		[[Category: Workstations]]

Larsbrinkhoff: /* Differences between Alpha and Graphics machines */ Link to Freeway Crossing article.

2025-06-26T10:04:45Z

Differences between Alpha and Graphics machines: Link to Freeway Crossing article.

← Older revision		Revision as of 10:04, 26 June 2025
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	==Differences between Alpha and Graphics machines==		==Differences between Alpha and Graphics machines==

	The first type of the IMLAC PDS-1 was called an ''Alpha machine'', and had a somewhat less capable display processor than the later ''Graphics machines''. There is no surviving documentation for the Alpha machine, but the details have been reverse engineered by Zachary Harper from the listing for the '''Freeway Crossing''' game.		The first type of the IMLAC PDS-1 was called an ''Alpha machine'', and had a somewhat less capable display processor than the later ''Graphics machines''. There is no surviving documentation for the Alpha machine, but the details have been reverse engineered by Zachary Harper from the listing for the '''[[Freeway Crossing]]''' game.

	On an Alpha machine, the D LDXA and D LDYA instructions load bits 4 to 10 into the accumulator MSB. On a Graphics machine, bits 6-11 load into the MSB. On both machines, bits 12-16 are loaded into the LSB, and the least significant "½ point" bit is cleared.		On an Alpha machine, the D LDXA and D LDYA instructions load bits 4 to 10 into the accumulator MSB. On a Graphics machine, bits 6-11 load into the MSB. On both machines, bits 12-16 are loaded into the LSB, and the least significant "½ point" bit is cleared.

Larsbrinkhoff: Programmable Display System. We ought to mention PDS-4 somewhere, but maybe not on a separate page.

2025-06-10T05:54:42Z

Programmable Display System. We ought to mention PDS-4 somewhere, but maybe not on a separate page.

← Older revision		Revision as of 05:54, 10 June 2025
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	The '''IMLAC PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]). It generally did not have any [[secondary storage]], and was mostly used only as a [[terminal]] on a larger system, communicating with it via an [[asynchronous serial line]].		The '''IMLAC PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]). PDS means Programmable Display System. It generally did not have any [[secondary storage]], and was mostly used only as a [[terminal]] on a larger system, communicating with it via an [[asynchronous serial line]].

	This computer was host to the first version of the game [[Maze War]]. As a terminal, it was used to develop the game [[Zork]], and edit the manuscript for the book ''Gödel, Escher, Bach''.		This computer was host to the first version of the game [[Maze War]]. As a terminal, it was used to develop the game [[Zork]], and edit the manuscript for the book ''Gödel, Escher, Bach''.
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	It had a [[vector graphics]] [[display]], controlled by a [[display program]] in the machine's [[main memory]] ([[core memory]], at that point in time). It also included a small 16-bit [[minicomputer]]; the two shared access to the main memory, with the display processor having priority for access. The [[Central Processing Unit\|CPU]] (said by many to be reminiscent of a [[PDP-8 family\|PDP-8]]) was built out of [[74 series]] [[integrated circuit\|ICs]], and had a classical [[front panel]] for control. The display was a [[cathode ray tube\|CRT]].		It had a [[vector graphics]] [[display]], controlled by a [[display program]] in the machine's [[main memory]] ([[core memory]], at that point in time). It also included a small 16-bit [[minicomputer]]; the two shared access to the main memory, with the display processor having priority for access. The [[Central Processing Unit\|CPU]] (said by many to be reminiscent of a [[PDP-8 family\|PDP-8]]) was built out of [[74 series]] [[integrated circuit\|ICs]], and had a classical [[front panel]] for control. The display was a [[cathode ray tube\|CRT]].

	There were several different variants; the original 'PDS-1' had an [[instruction]] [[cycle time]] of 2.0 μsec, and the 'PDS-1D' had a cycle time of 1.8 μsec, but seems otherwise to have been almost identical. There were also 'Alpha' and 'Graphics' versions (see below); the PDS-1D was a 'Graphics' machine.		There were several different variants; the original 'PDS-1' had an [[instruction]] [[cycle time]] of 2.0 μsec, and the 'PDS-1D' had a cycle time of 1.8 μsec, but seems otherwise to have been almost identical. There were also 'Alpha' and 'Graphics' versions (see below); the PDS-1D was a 'Graphics' machine. The last model was called PDS-4, with a memory cycle of "less than a microsecond" and optional floating point hardware.

	==Differences between Alpha and Graphics machines==		==Differences between Alpha and Graphics machines==

Jnc: /* External links */ Another copy of 'IMLAC PDS-1D Programming Guide'

2025-06-09T15:00:06Z

External links: Another copy of 'IMLAC PDS-1D Programming Guide'

← Older revision		Revision as of 15:00, 9 June 2025
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	* [http://www.bitsavers.org/pdf/imlac/ imlac] - documentation at [[Bitsavers]]		* [http://www.bitsavers.org/pdf/imlac/ imlac] - documentation at [[Bitsavers]]
	** [http://www.bitsavers.org/pdf/imlac/PDS-1_TechnicalMan.pdf IMLAC PDS-1 Programmable Display System Preliminary Technical and Operator Manual]		** [http://www.bitsavers.org/pdf/imlac/PDS-1_TechnicalMan.pdf IMLAC PDS-1 Programmable Display System Preliminary Technical and Operator Manual]
	** [http://www.bitsavers.org/pdf/imlac/PDS-1D_ProgrammingGuide.pdf IMLAC PDS-1D Programming Guide]		** [http://www.bitsavers.org/pdf/imlac/PDS-1D_ProgrammingGuide.pdf IMLAC PDS-1D Programming Guide] <!-- also http://www.ubanproductions.com/ImlacDocs/PDS-1D_ProgrammingGuide.pdf -->
	* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]		* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]
	** [http://www.ubanproductions.com/imlac_sw.html Imlac Software Library] - includes many IMLAC documents, not all of which are at Bitsavers (above)		** [http://www.ubanproductions.com/imlac_sw.html Imlac Software Library] - includes many IMLAC documents, not all of which are at Bitsavers (above)

Jnc: Jnc moved page Imlac PDS-1 to IMLAC PDS-1: Case as per original docs

2025-06-09T14:42:08Z

Jnc moved page Imlac PDS-1 to IMLAC PDS-1: Case as per original docs

← Older revision		Revision as of 14:42, 9 June 2025
(No difference)

Jnc: Expand description to a basic thumbnail; add ext links to manuals, etc

2025-06-09T14:40:20Z

Expand description to a basic thumbnail; add ext links to manuals, etc

← Older revision		Revision as of 14:40, 9 June 2025
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	An '''~~Imlac~~ PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]])~~, with a [[vector graphics]] [[display]]~~. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.		The '''IMLAC PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]). It generally did not have any [[secondary storage]], and was mostly used only as a [[terminal]] on a larger system, communicating with it via an [[asynchronous serial line]].

	This computer was host to the first version of the game [[Maze War]]. As a terminal, it was used to develop the game [[Zork]], and edit the manuscript for the book ''Gödel, Escher, Bach''.		This computer was host to the first version of the game [[Maze War]]. As a terminal, it was used to develop the game [[Zork]], and edit the manuscript for the book ''Gödel, Escher, Bach''.

	~~{{stub}}~~		It had a [[vector graphics]] [[display]], controlled by a [[display program]] in the machine's [[main memory]] ([[core memory]], at that point in time). It also included a small 16-bit [[minicomputer]]; the two shared access to the main memory, with the display processor having priority for access. The [[Central Processing Unit\|CPU]] (said by many to be reminiscent of a [[PDP-8 family\|PDP-8]]) was built out of [[74 series]] [[integrated circuit\|ICs]], and had a classical [[front panel]] for control. The display was a [[cathode ray tube\|CRT]].

			There were several different variants; the original 'PDS-1' had an [[instruction]] [[cycle time]] of 2.0 μsec, and the 'PDS-1D' had a cycle time of 1.8 μsec, but seems otherwise to have been almost identical. There were also 'Alpha' and 'Graphics' versions (see below); the PDS-1D was a 'Graphics' machine.

	==Differences between Alpha and Graphics machines==		==Differences between Alpha and Graphics machines==

	The first type of the ~~Imlac~~ PDS-1 was called an ''Alpha machine'', and had a somewhat less capable display processor than the later ''Graphics machines''. There is no surviving documentation for the Alpha machine, but the details have been reverse engineered by Zachary Harper from the listing for the '''Freeway Crossing''' game.		The first type of the IMLAC PDS-1 was called an ''Alpha machine'', and had a somewhat less capable display processor than the later ''Graphics machines''. There is no surviving documentation for the Alpha machine, but the details have been reverse engineered by Zachary Harper from the listing for the '''Freeway Crossing''' game.

	On an Alpha machine, the D LDXA and D LDYA instructions load bits 4 to 10 into the accumulator MSB. On a Graphics machine, bits 6-11 load into the MSB. On both machines, bits 12-16 are loaded into the LSB, and the least significant "½ point" bit is cleared.		On an Alpha machine, the D LDXA and D LDYA instructions load bits 4 to 10 into the accumulator MSB. On a Graphics machine, bits 6-11 load into the MSB. On both machines, bits 12-16 are loaded into the LSB, and the least significant "½ point" bit is cleared.
Line 16:		Line 18:

	On an Alpha machine, incrementing or decrementing the MSB is done according to the scale factor. On a Graphics machine, it's done by 1.		On an Alpha machine, incrementing or decrementing the MSB is done according to the scale factor. On a Graphics machine, it's done by 1.

			{{semi-stub}}

	==External links==		==External links==

			* [http://www.bitsavers.org/pdf/imlac/ imlac] - documentation at [[Bitsavers]]
			** [http://www.bitsavers.org/pdf/imlac/PDS-1_TechnicalMan.pdf IMLAC PDS-1 Programmable Display System Preliminary Technical and Operator Manual]
			** [http://www.bitsavers.org/pdf/imlac/PDS-1D_ProgrammingGuide.pdf IMLAC PDS-1D Programming Guide]
	* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]		* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]
			** [http://www.ubanproductions.com/imlac_sw.html Imlac Software Library] - includes many IMLAC documents, not all of which are at Bitsavers (above)
	* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]		* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]
	* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/Screen%20Addressing%20in%20FREEWAY%20(1971)%20for%20the%20IMLAC%20PDS-1.pdf Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1]		* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/Screen%20Addressing%20in%20FREEWAY%20(1971)%20for%20the%20IMLAC%20PDS-1.pdf Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1]

	[[Category: Workstations]]		[[Category: Workstations]]

Larsbrinkhoff: Claim to fame.

2025-06-09T12:42:01Z

Claim to fame.

← Older revision		Revision as of 12:42, 9 June 2025
Line 1:		Line 1:
	An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.		An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.

			This computer was host to the first version of the game [[Maze War]]. As a terminal, it was used to develop the game [[Zork]], and edit the manuscript for the book ''Gödel, Escher, Bach''.

	{{stub}}		{{stub}}

Larsbrinkhoff: Differences between Alpha and Graphics machines

2025-06-09T07:30:44Z

Differences between Alpha and Graphics machines

← Older revision		Revision as of 07:30, 9 June 2025
Line 2:		Line 2:

	{{stub}}		{{stub}}

			==Differences between Alpha and Graphics machines==

			The first type of the Imlac PDS-1 was called an ''Alpha machine'', and had a somewhat less capable display processor than the later ''Graphics machines''. There is no surviving documentation for the Alpha machine, but the details have been reverse engineered by Zachary Harper from the listing for the '''Freeway Crossing''' game.

			On an Alpha machine, the D LDXA and D LDYA instructions load bits 4 to 10 into the accumulator MSB. On a Graphics machine, bits 6-11 load into the MSB. On both machines, bits 12-16 are loaded into the LSB, and the least significant "½ point" bit is cleared.

			On an Alpha machine, beam deflection from the MSB is scaled up by 9 LSB units. On a Graphics machine, the MSB is scaled up by 16 LSB units. (The LSB least significant bit is 0.5 units.)

			On an Alpha machine, incrementing or decrementing the LSB does not add any carry to the MSB. The LSB can go outside 0-15 units; exactly by how much is unknown. On an Graphics machine, going outside 0-15 wraps around and carries to the MSB.

			On an Alpha machine, incrementing or decrementing the MSB is done according to the scale factor. On a Graphics machine, it's done by 1.

	==External links==		==External links==
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	* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]		* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]
	* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]		* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]
			* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/Screen%20Addressing%20in%20FREEWAY%20(1971)%20for%20the%20IMLAC%20PDS-1.pdf Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1]

	[[Category: Workstations]]		[[Category: Workstations]]

Jnc: +Ext link

2023-03-29T13:35:57Z

+Ext link

← Older revision		Revision as of 13:35, 29 March 2023
Line 1:		Line 1:
	An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.		An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.

			{{stub}}

	==External links==		==External links==

	* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]		* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]
			* [http://www.blinkenlights.com/classiccmp/imlac/ Imlac PDS-1]
	~~{{stub}}~~

	[[Category: Workstations]]		[[Category: Workstations]]

Jnc: +External links, link

2019-02-21T15:08:37Z

+External links, link

← Older revision		Revision as of 15:08, 21 February 2019
Line 1:		Line 1:
	An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.		An '''Imlac PDS-1''' was a very early [[workstation]] (1970, well before the [[Xerox Alto]]), with a [[vector graphics]] [[display]]. It generally did not have any [[secondary storage]], and was only a [[terminal]] on a larger system.

			==External links==

			* [http://www.ubanproductions.com/imlac.html Imlac Anatomy]

	{{stub}}		{{stub}}

	[[Category: Workstations]]		[[Category: Workstations]]