Freeway Crossing - Revision history

Larsbrinkhoff: Resolve link for Sigma 5.

2025-07-11T07:15:28Z

Resolve link for Sigma 5.

Jnc: Add a number of links; minor tweaks

2025-06-28T17:34:12Z

Add a number of links; minor tweaks

Larsbrinkhoff: I want in on this.

2025-06-28T06:42:46Z

I want in on this.

Larsbrinkhoff: /* External links */ Add "Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1"

2025-06-27T06:03:10Z

‎External links: Add "Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1"

Larsbrinkhoff: Recent development.

2025-06-26T10:36:21Z

Recent development.

Larsbrinkhoff: First draft.

2025-06-26T10:23:33Z

First draft.

New page

[[Image:FreewayCrossing.png|thumb|right|300px|Freeway Crossing running on a real IMLAC PDS-1]]

Around 1971, student programmer Michael Irrgang wrote a game called Freeway Crossing. He made it for Dr Earl Hunt for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the [[IMLAC PDS-1]] - the so-called "Alpha machine". The code was assembled using punched cards on an XDS Sigma 5 at the Computer Science department.

The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally. This game was probably the first in the genre typically exemplified by the Frogger arcade game.

{{semi-stub}}

==External links==

* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/freeway.pdf Assembly listing]
* [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/freeway.lst Scanned listing transcribed into text]
* [https://www.youtube.com/watch?v=fj6-XjxbYOs The game running on an emulator]
* [https://mastodon.sdf.org/@icm/114746096081388111 The game running on a real IMLAC PDS-1]
* [https://dl.acm.org/doi/pdf/10.1145/873641.873648 Paper by Earl Hunt describing the UofW CS facilities], including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.

@@ Line 1: / Line 1: @@
 [[Image:FreewayCrossing.png|thumb|right|300px|Freeway Crossing running on a real IMLAC PDS-1]]
-Around 1971, student programmer Michael Irrgang wrote a [[video game]] (one of the earliest) called '''Freeway Crossing''', for the [[IMLAC PDS-1]]. He wrote it for Dr. Earl Hunt, for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the PDS-1 - the so-called "Alpha machine".  The code was [[assembler|assembled]] using [[punched card]]s on an [[Xerox|XDS]] [[Xerox Sigma 5|Sigma 5]] at the Computer Science department.  Irrgang retained a copy of the assembly listing, which was later scanned and transcribed.
+Around 1971, student programmer Michael Irrgang wrote a [[video game]] (one of the earliest) called '''Freeway Crossing''', for the [[IMLAC PDS-1]]. He wrote it for Dr. Earl Hunt, for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the PDS-1 - the so-called "Alpha machine".  The code was [[assembler|assembled]] using [[punched card]]s on an [[Xerox|XDS]] [[SDS Sigma series|Sigma 5]] at the Computer Science department.  Irrgang retained a copy of the assembly listing, which was later scanned and transcribed.
 The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally.  This game was probably the first in the genre typically exemplified by the [[Frogger]] [[arcade game]].

@@ Line 1: / Line 1: @@
 [[Image:FreewayCrossing.png|thumb|right|300px|Freeway Crossing running on a real IMLAC PDS-1]]
-Around 1971, student programmer Michael Irrgang wrote a game called Freeway Crossing. He made it for Dr Earl Hunt for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the [[IMLAC PDS-1]] - the so-called "Alpha machine".  The code was assembled using punched cards on an XDS Sigma 5 at the Computer Science department.  Irrgang retained a copy of the assembly listing, which was later scanned and transcribed.
+Around 1971, student programmer Michael Irrgang wrote a [[video game]] (one of the earliest) called '''Freeway Crossing''', for the [[IMLAC PDS-1]]. He wrote it for Dr. Earl Hunt, for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the PDS-1 - the so-called "Alpha machine".  The code was [[assembler|assembled]] using [[punched card]]s on an [[Xerox|XDS]] [[Xerox Sigma 5|Sigma 5]] at the Computer Science department.  Irrgang retained a copy of the assembly listing, which was later scanned and transcribed.
-The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally.  This game was probably the first in the genre typically exemplified by the Frogger arcade game.
+The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally.  This game was probably the first in the genre typically exemplified by the [[Frogger]] [[arcade game]].
-In 2025, the game was updated with conditionals for also running on a regular "Graphics machine" and tested on a real IMLAC PDS-1.
+In 2025, the game was updated with [[conditional assembly|conditionals]] for also running on a IMLAC PDS-1 "Graphics machine" variant, and tested on a real one.
 {{semi-stub}}

← Older revision		Revision as of 06:42, 28 June 2025
Line 17:		Line 17:
	* [https://mastodon.sdf.org/@icm/114746096081388111 The game running on a real IMLAC PDS-1]		* [https://mastodon.sdf.org/@icm/114746096081388111 The game running on a real IMLAC PDS-1]
	* [https://dl.acm.org/doi/pdf/10.1145/873641.873648 Paper by Earl Hunt describing the UofW CS facilities], including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.		* [https://dl.acm.org/doi/pdf/10.1145/873641.873648 Paper by Earl Hunt describing the UofW CS facilities], including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.
		+
		+	[[Category: Video Games]]

@@ Line 13: / Line 13: @@
 * [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/freeway.pdf Assembly listing]
 * [https://github.com/larsbrinkhoff/imlac-software/blob/master/washington/freeway.lst Scanned listing transcribed into text]
 * [https://www.youtube.com/watch?v=fj6-XjxbYOs The game running on an emulator]
 * [https://mastodon.sdf.org/@icm/114746096081388111 The game running on a real IMLAC PDS-1]
 * [https://dl.acm.org/doi/pdf/10.1145/873641.873648 Paper by Earl Hunt describing the UofW CS facilities], including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.