ATLAS drum store
From Object Wiki
| Atlas drum store | |
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| Manufacturer | Ferranti |
| Production years | 1962 - ? |
| Production location | Chilton |
The first of three Atlas computers became operational in 1962, as a joint development between Manchester University, Ferranti and Plessey. It was arguably one of the world's first supercomputers, and the fastest computer in the world until the release of the CDC 6600.
Two other Atlas machines were built: one for British Petroleum and the University of London and one for the Atlas Computer Laboratory at Chilton near Oxford. A derivative system was built by Ferranti for Cambridge University, called the Titan or Atlas 2, which had a different memory organisation (without drums), and ran a time-sharing operating system developed by Cambridge Computer Laboratory.
This Storage Drum is from the Chilton Atlas.
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[edit] How it works
A magnetic drum has a ferric oxide coating on the outer surface of the drum which is used to record data in parallel tracks around the circumference. The drum revolves at high speed so that the data is repeatedly presented to the read/write head(s) arranged around the outside. In the Atlas drum there was a read/write head for each track (some other types of drum had a single head which could be moved from track to track like a modern disc drive).
The magnetic drum store on Atlas 1 was used to support paging. Nowadays, we would call it a swap file. Atlas 1 was the first computer to have paging which is now almost universal. Each drum contained 24K 48 bit words of store, organised into 512 word pages, which could be read into main memory as required, but which resulted in the eviction of another, not recently used page from main memory to the drum. Each Atlas 1 had four such drums though it would have been possible to vary this.
[edit] Memories
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Do you remember the ATLAS supercomputer? Add your memories. |
[edit] In the Science Museum's Records
Inv:1974-409 Source: SRC ATLAS Computer laboratory