(c) Chris Burton Small-Scale Experimental Machine 1

The “Baby” Re-born

Background to an historic event

Why the replica was built

How the replica was built

Demonstration of the working machine

(c) Chris Burton Small-Scale Experimental Machine 2

The Cathode Ray Tube Store

FC Williams and Tom Kilburn

How the store worked

Kilburn’s important report - December 1947

The need for realistic testing

(c) Chris Burton Small-Scale Experimental Machine 3

Freddie Williams and Tom KilburnIn 1950

(c) Chris Burton Small-Scale Experimental Machine 4

Regenerating the information

PICKUP PLATE

AMPLIFIERDISCRIMINATING

CIRCUIT

(c) Chris Burton Small-Scale Experimental Machine 5

The Need for Realistic Testing

The Small-Scale Experimental Machine

Sufficient functionality to be “universal”

Sufficiently simple for quick results

Designed to be expandable in functionality and capacity

Only one arithmetic operation - subtraction

(c) Chris Burton Small-Scale Experimental Machine 6

Small-Scale Experimental Machine - schematic diagram

(c) Chris Burton Small-Scale Experimental Machine 7

The Illustrated London News

(c) Chris Burton Small-Scale Experimental Machine 8

The First Program

Reliability gradually improved in June 1948

Kilburn’s program to find highest factor of a number

It succeeded with a small number after a run of a few seconds at about 11.00 am on 21st June 1948

(c) Chris Burton Small-Scale Experimental Machine 9

The First program

From a notebook kept by Geoff Tootill

(c) Chris Burton Small-Scale Experimental Machine 10

Dots & Dashes

(c) Chris Burton Small-Scale Experimental Machine 11

The Historic Event

The first time in the world that a stored-program computer worked

Monday, 21st June 1948, about 11:15The “Baby” was the World’s first

Universal Computing MachineNearly all modern computers are “like”

that.

(c) Chris Burton 12

The Computer Conservation Society

The Small-Scale Experimental Machine Rebuild Project

THE MUSEUMOF SCIENCE &INDUSTRY INMANCHESTER

(c) Chris Burton Small-Scale Experimental Machine 13

Project Goal

“To construct a working replica of the Manchester University Small-Scale Experimental Machine by Sunday, 21st June 1998 - the 50th anniversary of the successful running of the world's first stored computer program - and to re-run that program.”

(c) Chris Burton Small-Scale Experimental Machine 14

SSEM - Design Studies

Key documents

Analysis of circuits - e.g., Clock Chassis

Analysis of photographs - e.g., Typewriter

Chassis identification

(c) Chris Burton Small-Scale Experimental Machine 15

Dai Edwards’ Drawing of the Clock Circuit

(c) Chris Burton Small-Scale Experimental Machine 16

Our CAD clock circuit

(c) Chris Burton Small-Scale Experimental Machine 17

Close up of Clock Chassis

(c) Chris Burton Small-Scale Experimental Machine 18

Our Computer-Aided-Design Drawing of Chassis Metalwork

(c) Chris Burton Small-Scale Experimental Machine 19

SSEM - Acquisition of Parts

Key items - valves and cathode ray tubes

Generosity of many individuals

(c) Chris Burton Small-Scale Experimental Machine 20

The Mark 1 in 1949

(c) Chris Burton Small-Scale Experimental Machine 21

Close-up of Mark 1 Typewriter

(c) Chris Burton

Cover of War Surplus

Catalogue

(c) Chris Burton Small-Scale Experimental Machine 23

Catalogue Page withPush Button Unit

(c) Chris Burton Small-Scale Experimental Machine 24

Five of the pioneer team in 1998

Tom Kilburn, Dai Edwards, Geoff Tootill, Tommy Thomas, Alec Robinson

(c) Chris Burton Small-Scale Experimental Machine 25

50th Anniversary

Kilburn and Tootill re-run the first program on 21st June 1998