Graphics at ACL

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Early On

The original graphics equipment in the Atlas Laboratory was a Benson-Lehner graph plotter that was moved over from Harwell early in 1964. This was an off-line device and a basic system for driving it was developed for Atlas.


Formal approval to purchase an SC4020 Microfilm Recorder came in January 1967 and the machine was in service by early 1968. Paul Nelson produced a system called SCFOR for FORTRAN users which was a low level set of routines for accessing the capabilities of the machine hardware plus some higher-level routines. Bob Hopgood produced a slightly higher-level graphics system for Algol users called GROATS. By 1969, both systems were in use and some support was provided for animation output.


In February, 1969 a case was made for purchasing an interactive graphics system. The two front runners were an Elliott Automation system and a PDP15 system from DEC. With the prices being relatively similar, the case was made to purchase the British Elliott Automation system even though the display system had a relatively slow orange phosphor (which would mean previewing of animated films would not be brilliant). Just before the paper was due to go the Atlas Computer Committee, Elliott's increased the price substantially (they had forgot to add VAT) and, in consequence, it was decided to make the case to purchase the PDP15 system instead. Being both cheaper and having a much faster phosphor on the display, it was more appropriate for animation previewing.

Bob Hopgood had to persuade Brian Oakley, then at the Department of Industry, that Atlas had a good case for a foreign purchase. The PDP15 arrived in October 1970 (without the display) and was initially installed in G18 with a local air conditioning system.

Graphics Section

Graham England joined in November 1969 on a 3-year appointment. With Bob Churchhouse leaving at the end of 1970, a formal Graphics Section was set up under Bob Hopgood and that stayed in existence until the end of 1971. The initial members were Bob Hopgood, Julian Gallop, Graham Englan and Paul Nelson (although formally Paul was a member of the Support Group). Dave Ralphs came as a Sandwich Student in 1971. Geoff Lickess, Mary Stapley and David Sedar were other Sandwich students early on. In October 1971, Alan Francis and Dave Toll joined the Section.

Bob Hopgood took over as Head of Basic Systems Software in January 1972, and Eric Thomas became head of the Graphics Section. He remained in charge until November 1974.


A replacement for the SC4020 had been under discussion since 1971 and a case was made to the Atlas Computer Committee in 1972 and a case to purchase specifically an FR80 in March 1973. This went to the Science Board in December 1973. Due to the Science Board's financial state at the time, a Working Party was set up to assess the case and, in consequence, an order was not placed until near the end of 1974 with delivery early in 1975.


The papers in this section concentrate on the graphics software made available during the life of the Laboratory. Specific software and hardware details are contained in the technology sections on the PDP15, SC4020 and FR80. Some items are: