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The Journal of the Computer Conservation Society

ISSN 0958-7403

Number 76

Winter 2016/17


Society Activity  
News Round-up  
God Save the King
An Early Musical program on the Ferranti Mark 1
David Link
Cleaning the Elliott 401 Computer Dominique Russell
Dennis Blackwell – a Life Susan Colley
A Chilton Atlas Ghost Story Chrissy Norris
The Tony Sale Award 2016 Martin Campbell-Kelly and others
Book Review : Archeology of Algorithmic Artefacts Doron Swade
50 Years Ago .... From the Pages of Computer Weekly Brian Aldous
Forthcoming Events  
Committee of the Society 
Aims and Objectives 

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Society Activity

EDSAC ReplicaAndrew Herbert

We continue to progress step-by-step through systems integration.

We have demonstrated main control successfully going through the order fetch / decode / execute cycle with the arithmetic unit.

The coincidence and store access circuits remain in place and commissioned: they will be integrated with main control once it has been shown to be fully functional.

The arithmetic unit is in Cambridge ready for transfer for TNMoC. It is substantially complete, undergoing final testing of the corner cases of the multiplication circuits.

After a long period of experimentation we have arrived at a solution for driving the nickel delay line stores from the storage recirculation units that would seem to give us reasonable operating characteristics — the main issue has been improving the signal to noise ratio on the output from the delay line back to the regeneration unit to minimise breakthrough from the input side. We have some suspicion our decision to put an isolated 0V rail on every chassis may well be exacerbating our problems, and of course our EDSAC lives in an electrically noisier environment than its predecessor.

Ducting and 1.5km of cabling has been installed to connect the delay lines to the recirculation units.

Next steps are to continue with the systems integration, design and build the the initial orders loading system, complete the input-output system and devices, build an operator’s desk and design and build a clock monitor.

David Allen, David Hartley and I have visited another lady EDSAC operator to gather more information on what it was like to work with EDSAC in the early days and some of the associated personalities.

A full EDSAC volunteer’s meeting took place on 1st October. On the following day we hosted the surviving EDSAC operators (all ladies) to show them progress so far and pick their brains on how the machine was operated day to day.

ICL 2966Delwyn Holroyd

The system continues to operate reliably. The only problems worth noting have been ongoing issues with the EHT power supplies of the two 7181 VDUs, which are caused by the crimped internal connections. Whilst the terminals are both still serviceable, some more work will be required in the near future.

Our Computer HeritageSimon Lavington & Rod Brown

OCH contains the beginnings of a write-up of the Modular One computer — see: We now need a volunteer who is interested in adding material to this section about the Modular One’s register-level architecture, instruction set, etc. Anyone with fond memories of a Modular One and an interest in writing technical descriptions is asked to get in touch with Simon Lavington.

BombeJohn Harper

We started the Bombe Rebuild Project over 20 years ago and have had it fully working and have regularly demonstrated it for almost ten years. It is now time to consider succession planning. Many of the original team are ‘not as young as they were’ and it is time to develop the team with younger blood.

Therefore we are looking for new recruits. When we say younger; it might be unrealistic to consider, but not rule out, those in work with younger families and other personal commitments: so likely candidates would be in their mid to late 50s, retired with a personal income, with basic professional engineering background but also with a ‘hands on’ experience and a talent to make things work without a significant support network. Electro-mechanical skills would be most appropriate but this should not rule out other backgrounds.

If you are interested please contact me using my details shown elsewhere in Resurrection.

Appeal for Help

The National Railway Museum is researching Total Operations Processing System (usually known as TOPS) the 1970s IBM 370 computer system for keeping track of British Railways’ rolling stock.

Were you a TOPS developer or user? Did you write TOPSTRANS software for British Railways, or help implement the scheme on the ground? Do you have knowledge of the pre-history of TOPS in the USA and its origins in IBM and Southern Pacific Railroads? Are you familiar with the origins of the IBM software in the US defence sector (SAGE)? If so, or would be keen to hear from you.

Further details at

ICT/ICL 1900Delwyn Holroyd, Brian Spoor, Bill Gallagher


A new issue tape has been created for version 6A using source recovered over the last couple of years from the MGS binary system. A clean install, compiling from this tape, binary compares with the MGS binary. We know there are potential source errors still in the source (absolute addresses instead of labels, etc.) so that different configurations to MGS give problems. A lot of these errors have been cleared during the create process, but it would be unrealistic to hope that they have all been corrected. A lot of testing now required.

PF56 Emulator

The CPU module appears to be working, as does the EDS30/60 module. Disc DCPs and OLTs can be loaded and run. The DDE module (1900 interface) still has to be completed.

Work has been paused in favour of the 7930 scanner implementation for the 1904S emulator, which will also be used for the PF56 communications module. It is easier to debug the 7930 against a 1900 Executive for which we have a compilation listing rather than the binary only EZ5A communications DCP.

Some useful information was obtained at the Punch Card Reunion at Stevenage in October, where the main topic was the PF56.

1904S Emulator

Running reliably, current work is to add a 7930 Scanner (see above). This is proving frustrating due to lack of documentation, but seems to work with teletypes and 7020 RJE terminals under E6RM, but fails miserably under GEORGE 3.

1905 Emulator

The 1974 magnetic tape rewind/unload problem has been resolved.

1901A Emulator

On long term hold, works with E1HS, but fails with E1DS fixed, overlays missing.


Further work is required on bug clearance, but a basic system is running. It is nowhere near release standard yet.


We are running Executives created from the ‘cleaned’ source, but have identified further ELWRO updates which will need to be removed.


Testing of the 7930 Scanner has led to the discovery of ELWRO amendments which need to be investigated and removed.


Building of a database of available programs continues. We have also written several short manuals on various utilities for which no documentation appears to exist, having ascertained a way to drive them (correctly or not) out of necessity.

We already have copies of the most common 1900 manuals, so it’s unusual to come across new ones. This month copies of Care and Handling of Recording Media and 1901 Console Operating (without Console Typewriter) were donated to TNMoC, the latter an ICT first edition from 1966.

Argus 700/BloodhoundPeter Harry

We welcomed CCS members to RAF Cosford on September 24th for a visit that included a presentation on restoring our Argus 700 and to see the computer in use as part of the Bloodhound missile simulator. The simulator, part of the UK’s cold war heritage, is the focus of our restoration work, it just happens to use Ferranti’s Argus 700. CCS members could see at first hand the work undertaken to restore the Argus 700 in what can be described as basic facilities. During the presentation, a brief explanation was given regarding one of the main obstacles overcome, replacement of the Argus 700’s obsolete disc drives. It is hoped that a full description of the Argus 700’s restoration will be available for inclusion in a future edition of Resurrection.

The Argus 700 now runs reliably, as does the Bloodhound simulator, so what next? The next is a change of focus, a move from being hardware orientated to one of software and program writing. Not an insignificant change as we started the restoration project with no previous Argus 700 knowledge, or experience. Help though is always at hand as over the years we have received advice and support from several ex-Ferranti engineers. Essential support when it came to understanding software error messages and converting the disc system on the Argus 700. Over the past four years of the restoration it was a case of getting the Argus 700 to run with an existing and compiled software application. There was no need to understand how to write a program as the Argus 700 just had to run and if it didn’t, it was a hardware problem. So what next? Learn how to program the Argus 700!

Argus 700 Console
The Argus 700 Control and Monitor Console

One obvious question is, why bother learning to program the Argus 700? The simulator runs and there is no need to modify the application software in any way. The answer is, we need to create test routines to exercise parts of the simulator system and the Argus 700 hardware. One goal is to write programs that can be used to test individual Argus 700 boards. A steep learning curve is now needed over the next few months but we do have the means to succeed. We can work at the bit and byte level using Ferranti’s Control and Monitor Panel (ME159), a unit that enables the monitoring of instructions as they execute by displaying the contents of the processor’s accumulator and registers as well as memory locations. At the other end of the software scale is the operating system (OSC245) and a Coral 66 compiler (OSX150). A start has been made in gaining some knowledge of how to use the Control and Monitor Panel but there is a long way to go. Help is always appreciated so if there are any ex Ferranti Argus 700 software engineers reading this who can share their knowledge, please get in touch.

CCS Website Information

The Society has its own website, which is located at It contains news items, details of forthcoming events, and also electronic copies of all past issues of Resurrection, in both HTML and PDF formats, which can be downloaded for printing. At, can be found emulators for historic machines together with associated software and related documents all of which may be downloaded. Note that this part of our website is under development. Further material will be added in due course.

SoftwareDavid Holdsworth


Volume IV of the Leo Manual has now been decorated with hot links and can be seen at:

I have very recently received a very positive response from Jim Austin about borrowing tapes from him.

Kidsgrove Algol

There has been much activity. Our re-engineering of the missing brick 20 is still making good progress. Brian Wichmann continues to explore the archives at Blythe House, and has recently discovered a hand-written copy of the missing brick. David Huxtable has been in contact with its original author who believes it to be close to that which was issued. We have not abandoned our re-engineered version, and are still considering whether it is worth copy-typing.

It is my intention that these documents (primarily design documents and flow diagrams) will eventually form part of the on-line presence of our preserved compiler system. Find an initial stab at incorporating such documents at

Harwell Dekatron/WITCHDelwyn Holroyd

This Halloween saw a special program of activities around the museum and the annual excuse for themed decoration of the WITCH area!

The artist John Yeadon recently visited the museum. Readers may remember the appeal earlier this year to find his 1983 work “Portrait of a Dead WITCH”, which was eventually located in a Manchester café bar. It was the first time John had seen the machine since he painted it at the Birmingham Museum of Science and Industry.

Operation has been generally trouble free with the exception of a couple of incidents. One of these was suspected to have been caused by dirt in a relay contact and cleared itself. The second unfortunately caused a day of downtime on a Saturday, however visitors did get a rare chance to witness the process of fault-finding on a 1950s computer. The symptom of the issue was seemingly random corruption of store locations during operation.

The problem was eventually traced to an intermittent partial short in a pulse generator valve which confusingly didn’t affect the output of the valve in question, but instead caused another circuit to malfunction due to the increased load on the input signal to the faulty valve. The unusual and intermittent nature of the fault caused more than the usual amount of head scratching amongst the team!

IBM GroupPeter Short

We have made good progress in creating information cards for those displays where they were missing. Each card can take quite a while to produce if we don’t already have the product information. After trawling our own documentation then the web, we can end up with little information or huge amounts. Either way, we update the online database first, and then create a summary on the card. In addition if there’s enough information online we create a QR code pointing at the web page.

Two Hursley departments have been having a major clearout and invited us to take what we wanted. One area yielded a lot of miscellaneous hardware, software and documentation. The other, the Storage Systems Development group, yielded a quantity of SSA disc adapter cards and hard discs. We also found a prototype for the Redwing hard disc, which had two actuators , whereas the finished disc only used one.

A Trolley Load of Storage Osprey - Redwing prototype
A Trolley Load of Storage Osprey — Redwing prototype

An IBM retiree has donated a set of framed IBM advertisements from the 1950s, extolling the lightning fast computing power of electro-mechanical machines and valve-powered computers. These now hang behind the Royal Army Pay Corps 705 console.


After the loss of an artefact out on loan that we reported earlier in the year, we have implemented more regular checks on loans and the people responsible. Unfortunately this revealed that our 011 electric hand punch, on loan to us from the Army, and loaned out to a Hursley department, has disappeared. The responsible manager had moved on, and we’ve not been able to find anyone who knows what happened. This was our only example of this punch, so our loans policy has been further revised to only lend items where we have at least two and preferably more.

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News Round-Up

Elsewhere in this edition, you will read about Strachey’s program for the Ferranti Mark 1 which played God Save the King on the hooter.

By co-incidence, that very subject came up in an edition of BBC Radio 4’s Today programme on the 1st of October 2016. Jack Copeland, a noted authority on Alan Turing, managed to get all the way through a long interview without mentioning Strachey at all, but discussed Turing at length giving the unfortunate impression that the latter was entirely responsible for the feat! Happily, the BBC’s web page at gives a more balanced view. There you will also find links to the interview and to a recently cleaned-up version of the 1951 BBC recording of God Save the King, and other tunes. Do note however, that the implication that Turing built the Mark 1 computer all by himself should not be taken seriously.


Our ever-active friends in the LEO Society have been at it again. On 29th November, 65 years to the day after LEO I became the first computer in the world to be applied to business, rather than scientific problems, a plaque has been unveiled in Lyons Walk, Hammersmith a short distance from the site of that momentous and pioneering event.

LOE plaque unveiling
Dame Stephanie ‘Steve’ Shirley who unveiled the plaque together with Professor Frank Land from the LEO Society.


In “Brexit” news, the Chancellor of the Exchequer has indicated that highly skilled workers may be exempt from the government’s planned immigration controls. Philip Hammond said he could not see why firms should be restricted from recruiting “high level” workers. The public was not concerned about controls on “computer programmers, brain surgeons, bankers”, he said (BBC News website).

This is the first time my social and economic status has been equated with that of a brain surgeon. Less pleased about the bankers though.


Starting in February 2017, the Science Museum’s new exhibition is all about robots. The centrepiece of the event is “Eric” a newbuild replica of a 1920s humanoid robot which seems to have disappeared once the novelty wore off. Externally, the Eric replica is a faithful re-creation of the original but its mechanisms are modern and it is computer-controlled. The Science Museum’s web page has details and a short video.

“George”, Tony Sale’s similar 1950s creation (see Resurrection 53) on loan from TNMoC, is also part of the exhibition but is pretty much original. The exhibition will run until September.


Readers might recall our Resurrection 71 article on the rather handsome STC Executel discovered at the National Trust property The Homewood. It turns out that it had been discarded in a skip at the house until somebody noticed that it fitted the space created for it in the office desk and retrieved it. Until we recently made contact (don’t ask) it was thought to be a telephone exchange rather than a telephone-cum-computer. Delighted to be of service!


Peter Cunningham has set up a website ( to give researchers and historians access to work produced by the INPUT organisation from 1975 to 2000. The collection contains research and materials specific to IT Software and Services Industry markets — more than 3,000 collection items

The service is offered free to students and researchers with a .edu or email address and available free for a trial period to all visitors.

The current website presents the results of the “Phase One” of our digitization effort — the scanning of all highest-priority INPUT deliverable items.

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God Save the King

David Link

In September 1951, the school teacher Christopher Strachey showed up in the computing laboratory of Manchester University with an algorithm of enormous length. After a couple of errors were fixed, the program ran straight through and finished by playing God Save the King on the built-in hooter (loudspeaker) of the Ferranti Mark 1 computer, which had been installed there in February.

This was only the second time a universal machine has been employed to play music the Australian CSIRAC having achieved the same feat in August 1951. On the 2nd of October 1951, the mathematician in charge of the lab, M.H.A. Newman, congratulated Strachey on his achievement of the melodic program in a letter, which allows a relatively precise dating of the event and is preserved in Bodleian library, Oxford.

A short time later, also in autumn 1951, a team from the BBC Children’s Hour recorded how the very early computer played God Save the King, Baa Baa Black Sheep and In the Mood, so by that time, the musical repertoire had already evolved. One of the engineers from the lab, Frank Cooper, asked for his own copy of the recording and the BBC team cut a second acetate disc for him, which survives in the possession of Christopher P. Burton.

Until now, it was completely unknown how Christopher Strachey programmed the machine to play music. But the author has unearthed the first God Save the King algorithm in Bodleian library (Strachey papers, CSAC 71.1.80 C.53), and a detailed description of it is given here.

The musical programs were made possible by a technical device of the Mark 1, the so-called hooter — a simple loudspeaker. The corresponding hoot instruction in the command set of the machine, /V, sent an electrical pulse to the speaker, which became “distinctly audible as something between a tap, a click, and a thump”, as Turing’s Handbook wrote. The order could be integrated into a cycle, e.g.

        FS	NS/V
        CS	FS/P

where the first sent the pulse to the speaker, and the second jumped back into the first line. Both instructions had a duration of four basic machine beats of 0.24 milliseconds length, so the period of both commands was 8 x 0.24 = 1.92 milliseconds and hence the frequency of the sound generated, 1000 / 1.92 = 521 Hertz, about C5. Since this was the smallest loop possible, the tone was the highest one the computer could emit. By calling /V “repeatedly and rhythmically”, wrote the handbook, “a steady note, rich in harmonics, can be produced.”. By constructing different loops, other tones could be programmed.

The hooter already existed on the Manchester Mark 1, the precursor of the Ferranti Mark 1, which developed organically out of the Small-Scale Experimental Machine SSEM, or “Manchester Baby” for short, from August 1948 on. In October 1950, Audrey Bates wrote a thesis On the Mechanical Solution of a Problem in Church’s Lambda-calculus, incorporating programs on the Manchester Mark 1, and reported that in the “Code of Instructions” decimal 1 or teleprinter E was the “Hooter operator”. Also in Turing’s first edition of the handbook from March 1951, there is an appendix on the “Pilot Machine (Manchester Computer Mark 1)” with a list of Computer Function Characters, where 15 or K meant “Hooter operates”. The code for the loudspeaker apparently changed several times.

The hoot function was put to use in several different ways. The handbook specified the following scenario for the above-mentioned simple loop: “This is used to enable the operator to be called to attend to the machine in some way. The simplest case is where the whole of a job is completed and it is required to clear the electronic stores and start something different.” Usage was so common that the so-called hoot stop was incorporated into “PERM”, two pages that contained the powers of two and the routine-changing sequence and were kept constantly available in the electronic store at the side of every program. In Christopher Strachey’s software for the game of draughts from 1951/2, the algorithm also entered the hoot stop if the user took too long to reply to the machine. According to Martin Campbell-Kelly, usage of this feature declined after a dramatic event had taken place: “[A] new user ran a programme that terminated on a hoot stop, with the volume full on. He looked for a switch to turn off the hooter and the only one that seemed possible was labelled HT. Unfortunately it was the high tension power supply; the machine took several days to repair!”

In the instruction sheet for the draughts program, Strachey described a more subtle way of tone-driven interaction with the software: “The machine gives a ‘pip-pip’ signal when it requires attention. It should always be restarted by operating KAC after it has been set appropriately.” So every time the algorithm had digested the user’s input, for example part of a move sequence, it was emitting a sound and passing control over to him, until he hit a key called KAC to indicate his input was complete. This procedure organised the whole flow of human interaction with the program.

A third function of the hooter was useful in debugging. The handbook wrote: “By putting hoot instructions into programmes [sic] at suitable points one is enabled to listen in to the progress of the routine. Some indication of what is going on is given by the rhythm of the clicks that are heard.” Dietrich G. Prinz, an early programmer on the Mark 1, remembered he was once congratulated on the “musical quality” of his software. Many of these diagnostic clicks can also be found in the source code of Strachey’s draughts program.

source code
Figure 1. The musical program, with annotations by the author.

The musical algorithm that played God Save the King was part of an interpretive trace routine which was 20 programming pages long and which Strachey had developed in parallel to his draughts on the suggestion of Turing. Its name was CHECKSHEET and on page 19, the melodic software was located. It was one of two ways to terminate the algorithm, hence the page was called ROUTINE CHECKSHEET EXIT2. Strachey had scribbled on the top right of the page “The King” to indicate the tune it played.

In the bottom half of the right column E, the frequency of the notes is found in teletype characters and written backwards from bottom to top. Hence the first tone values are in rows £E, VE, XE, etc. Only the first two characters are used and the first line, @/@/, is decremented by one to E/@/ before it is employed, so the 16 numbers for note frequencies are 1 1 2 0 1 2, 3 3 4 3 2 1, 2 1 0 1 (rows £E to TE). Above the tone values, also in the right column and again backwards from bottom to top, the note durations are located, numbers in Baudot code between 1024 and 4128.

The actual program producing the music is found in the left column, rows // to P/. Its main function was to define loops mixing arithmetic five-beat instructions and non-arithmetic four-beat instructions. This is because by using only orders of one duration to define the frequency, there is no way that a good enough musical scale can be produced. It is essential to have finer control of the length of the loop. Using suitable mixtures of four- and five-beat instructions allowed increments of 0.24 milliseconds and that enabled a reasonable scale to be produced. We take the first note generated as an example.

In row W/, B-tube 7 is set to one of the values for the note durations in rows KE to /E, in our example to KE = S/@/. Two lines below, in row Y/, B-tube 6 is set to one of the values for the note frequency in rows £E to TE, in our example to E/@/, the content of line £E decremented by one in the preceding rows T/ to L/. After that, in line P/, command S/IP is found, an unconditional jump. Before it is obeyed, the content of B-tube 6 is added to it, in our example the first two signs of E/@/. This modifies the address the operation jumps to, the final command now being I//P, and in row I/, the first two characters are :/. The algorithm thus jumps to this line and continues execution at the beginning of loop 8 (L8, cf. Figure 1), in row S/. The addresses of the five possible loops are found in the first two signs of lines S/ to D/ and have been framed in Figure 1.They are selected in the way just described by addition of B-tube 6 to the control transfer instruction.

Loop 8 in rows S/ to N/ begins with what is called a “dummy command”, an order with an operation code that has not been assigned a function. It takes four basic beats of the machine, and hence has a duration of 4 × 0.24 = 0.96 milliseconds. The following four commands with operation code T: repeatedly clear the accumulator of the computer and as arithmetic instructions each take five beats, 1.2 milliseconds. After that the hoot order proper, /V, is found, which takes another four beats, then a four-beat command that decrements B-tube 7 holding the note duration by 32 and finally a four-beat instruction that jumps back to the beginning of the loop if B-tube 7 is still positive. The total length of loop 8 is therefore 4 + 5 + 5 + 5 + 5 + 4 + 4 + 4 = 36 beats, and its period 36 × 0.24 = 8.64 milliseconds. That means the frequency produced in this loop is 1000 / 8.64 = 115.7 Hertz, slightly below B2 (116.54 Hz).

To determine the duration of the note, the software sets B-tube 7 to one of the values in rows KE to /E. At the end of the loop, as we just saw, the B-tube is decremented by 32 and loop 8 repeated if the result is still positive. The duration of the first note is found in row KE, S/@/, which is 2053 converted to decimal notation. If we divide this value by its decrement, 32, we get 2053 / 32 = 64, hence the loop is repeated 64 times. This results in a note duration of 64 × 8.64 = 553 milliseconds, approximately half a second. In a similar fashion, all note frequencies and durations can be determined, and they are found for the complete tune in the following tables, first the frequencies, then the durations.

Teletype Decimal Loop no. Beats Period Freq. Note Note freq. Derivation Word
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 God
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 save
@/ 2 L7 32 7.68 130.2 C3 130.81 0.61 our
// 0 L9 38 9.12 109.6 A2 110 0.4 grac-
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 ious
@/ 2 L7 32 7.68 130.2 C3 130.81 0.61 King.
A/ 3 L7b 29 6.96 143.7 D3 146.83 3.13 Long
A/ 3 L7b 29 6.96 143.7 D3 146.83 3.13 live
:/ 4 L6 27 6.48 154.3 E3 155.56 1.26 our
A/ 3 L7b 29 6.96 143.7 D3 146.83 3.13 no-
@/ 2 L7 32 7.68 130.2 C3 130.8 0.61 ble
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 King.
@/ 2 L7 32 7.68 130.2 C3 130.81 0.61 God
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 save
// 0 L9 38 9.12 109.6 A2 110 0.4 our
E/ 1 L8 36 8.64 115.7 B2 116.54 0.84 King.
Figure 2. Note frequencies for musical program.
Teletype Decimal Repetition Period Duration ms Duration fraction Word
S/@/ 2053 64 8.64 553 ¼ God
//@/ 2048 64 8.64 553 ¼ save
/¼@/ 2304 72 7.68 553 ¼ our
/"@/ 2912 91 9.12 830 grac-
//E/ 1024 32 8.64 276 ious
/¼@/ 2304 72 7.68 553 ¼ King.
/T@/ 2560 80 6.96 557 ¼ Long
/T@/ 2560 80 6.96 557 ¼ live
/P@/ 2752 86 6.48 557 ¼ our
/OA/ 3840 120 6.96 835 no-
/:E/ 1152 36 7.68 276 ble
//@/ 2048 64 8.64 553 ¼ King.
/¼@/ 2304 72 7.68 553 ¼ God
//@/ 2048 64 8.64 553 ¼ save
/ME/ 1920 60 9.12 547 ¼ our
/E:/ 4128 129 8.64 1115 ½ King.
pause 288 69
Figure 3. Note durations for musical program.

Since the periods of the notes differ, the number of repetitions needed to produce a certain duration is different depending on the frequency. For the first note, repeating the loop 64 times results in 553 milliseconds, while the sixth loop with 32 beats and a 7.68 milliseconds period needs to be repeated 72 times to yield the same length.

When the note is over, the algorithm leaves the loop in row N/. In the following lines commands are found which prepare playing the next tone. In rows F/ to K/, an empty loop is located, which is repeated 32 times. There are eight single commands of four beats, 8 × 4 = 32 beats duration, which, when added to the 32 × 8 = 256 beats of the loop, add up to 288 beats or 69.12 milliseconds, which is the length of the pause between the notes. The control transfer in line P/, similar to the one in line N/, jumps back to the beginning of one of the loops and starts playing a new tone.

The art of performing a tune on the Ferranti Mark 1 thus essentially consisted in finding the right mixture of commands of different lengths, which took the right amount of time, before the next pulse was sent to the speaker. The real function of the instructions used was unimportant, it was only the temporal aspect that mattered. In this way, the musical program shows an important property of the Ferranti Mark 1 and other universal machines: driven by a clock and performing immaterial activities in a number of basic beats and with a certain rhythm, the computer can be understood as a purely musical device. All that is needed is connecting a “hooter” at the right place in the circuitry and ignoring all functional meaning of the operations. The reason why a musical instruction was part of the command set of several early machines may be the fact that it was so easy to implement on the hardware side. The rhythmicity of the pulses in the different organs of the computer was already there, waiting to be heard.

David Link specialises in computer-based art but has a particular interest in the very early Manchester University/Ferranti computers. He was the first winner of the Tony Sale Award for his researches into “Love Letters” Christopher Strachey’s program for generating random communications of an intimate nature.

A re-creation of the sound generated by the program may be found at

David Link can be contacted at and his website is

Cleaning the Elliott 401 Computer

Dominique Russell
As you open a door to the Elliott 401 you are greeted by a mass of electrical components; wires, connectors, sockets and electronic valves. The Elliott-NRDC 401 is one of the first electronic computers, developed in 1952 when machines of this type could span four metres in length and weigh over a ton.
Elloitt 401
Elliott-NRDC 401 Historic Computer c. 1953 © CCS

Using wartime radar technology the Elliott 401 was considered experimental and, as a prototype tested a number of new techniques in computing and mathematical statistics. Initially its inbuilt functions consisted of addition, subtraction and multiplication. There was no capability for text, therefore the results were purely numerical and had to be annotated by hand.

Douglas Rees
Douglas Rees the Manager of the Machine c. 1955 © 2006 D.J.Pentecost

A computer is only as good as the people around it; the Elliott 401 owes much of its success to Douglas Rees, the manager of the machine or “computer” who aided its users when it was operational. At this time the term computer was also given to the people who worked on the technology.

By 1955 a charge of £25 per hour was fixed in place for any users wishing employ the Elliott’s functions.

After performing solidly for 12 years, in 1965 the Elliott was donated to the Science Museum. Today we are still giving the Elliott 401 the same attention at the museum. The computer features in Mathematics: The Winton Gallery, an exciting new gallery opened on 8th December 2016. However, we first needed to clean and prepare it after 60 years’ worth of storage.

As a Collections Assistant in the Science Museum’s conservation team I was involved in cleaning the Elliott 401.

Standing at over two metres tall the Elliott is a cased metal structure with two console units attached. What I find interesting about this huge machine is its inner-workings; the interior mechanics resemble something so unlike computers today. The Elliott demonstrates a distinct age in which computing was not only visually constructive but relied heavily on human interaction.

A team of eight people was involved in the cleaning of Elliott 401, including conservators and collections assistants.

cleaning the machine
Masterplan Conservator Jennifer Bainbridge & Masterplan Collections Assistant Dominique Russell with Elliott-NRDC 401 Historic Computer Photo: B. Cairncross

We started the cleaning by using a brush and vacuum followed by a soft microfibre cloth to remove the exterior layers of dust. Inside the Elliott 401 sit hundreds of wires amongst connectors and sockets that have allowed a considerable amount of dirt to build up over time. We swabbed wire after wire using several techniques ideal for picking up residue and dust, including a small putty based material called Groom Stick, a natural vulcanised rubber called Smoke Sponge and a cotton swab coated in distilled water or Industrial Methylated Spirit.

After many hours of cleaning the Elliott-NRDC 401 is now installed in the new gallery.

Mathematics: The Winton Gallery opened on the 8th December 2016 and is free to visit.

For further information visit

Dominique Russell is a Collections Assistant at the Science Museum.

Dennis Blackwell — A Life

Susan Colley
Not long before his recent sad passing, Dennis Blackwell — a senior figure in the early ICL story — was interviewed on camera by his daughter Susan Colley. This is an extract from her précis of that interview.

In 1958 Dennis Blackwell saw a position advertised at the English Electric Research Laboratories at Stafford. They were looking for someone to work on the possible commercial application of computers in business. Along with two or three other people he was duly recruited to work on the commercial application of the DEUCE computer. Two of the very early examples of daily data processing that Dennis did in the late 1950s were the computer programming for rolling stock from Crewe Station and the programming of automating the selection of orders in the order book for Samuel Fox’s Sheffield steel mill. Both programs worked well but the efficient working of the Crewe rolling stock program was thwarted by a strike at Garston Docks and so nothing followed the predicted pattern!

In the early 1960s, Dennis had started to move from the programming of computers to managing the people who were all part of the sales support system that, at that time, went with purchasing a computer. By the mid-1960s Dennis also had responsibility for the software development as well as for the non-scientific machines being produced by English Electric. As buying a computer was still only in the domain of large companies such as Midland Bank and Commercial Union, he was dealing with not only the software but also a large number of people who needed to be recruited and trained in how to operate these computers and then despatched to work alongside the purchasing company’s staff.

By early 1967 English Electric had merged with the Lyons Computer Company and taken over Elliott Automation leaving only ICT as the other main leader in the British computer world. An English Electric memo to Dennis dated 26th June 1967 stated “For some time past the Ministry of Technology has been pressing ICT and ourselves to co-operate in the development of a family of computers which would be fully competitive with anything IBM has to offer in about five years time. This new family would, of course, have to pick up the forward development of both the ICT 1900 Series and the English Electric System 4 and work programmed for either of these earlier families would have to be readily transferrable to it.”

Dennis, John Pinkerton and Colin Hayley as English Electric’s representatives with three from ICT met at the Cavendish Hotel in in London to discuss this prospect. The net result was reported to Government that there needed to be a single commercial entity. Hence International Computers was formed on 1st August 1968.

As the two companies merged to form ICL, Dennis took over all the responsibility for the software of both companies with the title Director of Systems Programming ICL managing about 2,500 people.

The quantity and variety of software and associated technical items that came with the amalgamation was enormous and so in about 1970 Dennis set up a large software organisation, Dataskil which greatly improved the structure within ICL.

Australia was lacking in a computer industry at this time and looked to Britain to aid its development. Dennis was responsible for interviewing and appointing the person responsible for developing the software house for ICL in Australia. Dennis and one of his senior managers conducted interviews in Australia but found a suitable Australian candidate in America, and duly appointed him.

In the UK there were about 17 different locations for software units as well as those in and around London. It was necessary to rationalise them into a sensible organisational shape. The Government suggested Middlesbrough as a good location! Peter Hall the ICL Director of Software was recommended by Dennis to look at Edinburgh, Scotland as a more viable alternative and they duly found a good location at Dalkeith Palace, a former home of the Duke of Buccleuch. It was close to the university for recruitment and close to amenities and therefore a good choice so ICL spent quite a bit of money in setting it up. This was Dennis’ contribution to the emergence of computer technology in Scotland.

American management was brought into ICL in the early seventies and Dennis’ job role altered and he became more involved with the wider links of computing. Dennis was responsible for putting together the ICL’s input to the Younger Report on Data Privacy, which formed the basis for the Data Protection principles as we know them today. When the Data Protection Act came into force much later on, circa 1984/86, a Data Protection Registrar was established at Wilmslow under Eric Howe who had been one of Dennis’ leading systems analysts with English Electric at Kidsgrove before the start of ICL.

Dennis also represented ICL on the National Electronics Council, as well as on the British Equipment Trade Association, and so in addition, aided these organisations input to the Younger Report. ICL’s involvement, through Dennis, with BETA was very important as it was the mandatory link to the British Standards Institute where standards are developed pertinent to the industry involved.

A Chilton Atlas Ghost Story

Chrissy Norris
When computers were young, rare and very, very expensive, they had to be used around the clock. And somebody had to staff the long, lonely, oh so lonely night shift. Are you sitting uncomfortably?...

There were usually seven of us on duty each night at that time, but you always had this strange feeling that somebody else was there too. One night I was sorting out a printer when I became vaguely aware of a blond chap walking down the corridor past me. It certainly wasn’t Jean or Trevor. “Oh yes”, said Jean when I got back to the Ops control room and mentioned what had happened; “that’s our ghost.”

The ghost was a well-known “resident” of Atlas. Late at night, with nobody around you could sometimes hear floor tiles creaking and the sound of the door opening. When I was on shift with Jean Smith we tried very hard to persuade the ghost make his presence felt. At 3 o’clock one morning we both went into the small room in the “Prime Area” and stood there, saying we weren’t going to leave until he’d given us a sign that he was there too. From out of nowhere a coin fell to the floor. Jean and I both got stuck in the door trying to get out of there quickly. We’ll not try that again.

From then on we all felt that the ghost was toying with us. I was listening to the radio one night, eyes closed, and next minute I’d been pushed out of my chair onto the floor. When Jean came back I said “Ha ha, very funny”. But she said she’d been in the shift tea-room all the time. We tended to go around together after that.


Several people saw the ghost, and all have said that he was blond and dressed in a military uniform; not RAF but the Canadian Air Force. The War Graves section of Harwell Cemetery contains the graves of 59 airmen and a member of The Royal Engineers from the WW2 period of whom four are Canadian, four Australian and two from New Zealand. It is believed that all of them died while stationed at RAF Harwell. Flight Sergeant Carl Alexis Bergsten has perhaps the saddest story to tell — on 25th October 1941 his ’plane crashed into an ammunition dump. Although Atlas wasn’t built until 20 years later, maybe he’s still trying to get his night-time bearings.

Tony Sale Award 2016

Martin Campbell-Kelly and others
The 2016 Tony Sale Award for computer conservation has been won by the Heinz-Nixdorf MuseumsForum for its evocative and educational reconstruction showing how ENIAC, one of the first electronic computers, was programmed.

ENIAC was programmed by plugging wires and turning knobs, a physical skillset quite different from those deployed today. The reconstruction of part of the huge 1946 American computer has the look and feel of the original, but has been simplified to make it readily understood and even programmable by non-specialists.

Chair of the judging panel, Professor Martin Campbell-Kelly said, “The HNF reconstruction captured the essence of the landmark ENIAC computer. The panel was particularly impressed at the thought and planning that went into making the reconstruction accessible to non-specialist audiences. Then the execution of the ideas produced an artefact that is robust and ideal for a hands-on museum display to demonstrate the physicality of early computer programming. Modern audiences are bound to be surprised and captivated by the reconstruction.”

The inspiration for the reconstruction was the HNF’s Ada Lovelace bicentenary celebration — the ENIAC was originally mostly programmed by women. Operating six days a week in the museum, the reconstructed ENIAC accumulator (a ‘register’ in modern terminology) is safe and robust enough to be operated by unsupervised visitors.

Campbell-Kelly concluded, “The judging panel has been especially pleased at the sheer variety of entries we are receiving for the Tony Sale Award for computer conservation. The ENIAC reconstruction is quite different to our previous winners: Dr David Link’s computer art installation, Love Letters; the IBM 1401 experience by the Computer History Museum; and the virtual reconstruction of the German 1930s Z1 mechanical computer. With such diversity and global interest, the Tony Sale Award is providing a great benchmark for the developing science and art of computer conservation.”

Other entries shortlisted for the 2016 award included

  • A restoration of a 1972 PDP-12 computer by the Rhode Island Computer Museum and,
  • From the Jim Austin Collection in York, England, the conservation of a 1980s IBM 3084 mainframe computer and a Cadlink computer aided design machine.
  • The restoration of a 1960s computer peripheral, an IBM 1403-N1 printer at TechWorks! VIntage IBM Computing Center, Binghamton, NY, USA. This outstanding project was nominated runner-up in a closely fought competition.

The award was presented at the London CCS meeting on Thursday 17th November and was followed by a fascinating presentation from Johannes Blobel who designed the exhibit and led the implementation team.

The Tony Sale Award is presented in remembrance of the late Tony Sale, one of the two co-founders of the Computer Conservation Society which runs the award.

Tony Sale was an inspirational figure whose efforts to reconstruct a Second World War Colossus codebreaking machine pioneered much of the present-day work of the Society.

The award is sponsored by Google to whom we are most grateful.

A video of the reconstructed ENIAC panel being demonstrated can be seen at

Eniac panel replica
Dr Jochen Viehoff (Director Heinz Nixdorf MuseumsForum) and Johannes Blobel with the ENIAC reconstruction and the Tony Sale Award at HNF. (Photo by Jan Braun/HNF.)

Book Review : Archaeology of Algorithmic Artefacts

Doron Swade

It is rare in Anglo-American history of computing to find a book that invokes Hegel, Kant, Foucault, Markov, Derrida, Saussure, Plutarch, Pushkin, Freud, Goethe, Kafka, Aristotle and Becket, and which interleaves their works with those of perhaps the more familiar figures of Turing, Williams, Kilburn, Flowers, Zuse, Strachey, Newman and Tutte amongst others.

David Link, based in Cologne, won the inaugural Tony Sale Award in 2012 for his art installation featuring the reconstruction of Christopher Strachey’s love letter program — a work that gave us a foretaste of his creative breadth and interdisciplinary scope. True to form this book is emphatically in the European tradition in that it does not recognise the familiar silos of historical discourse that tend to focus on wartime and post-WWII electronic computing and, in doing so, eschew more philosophical approaches or the history of ideas. What can be daunting about David Link’s work is not only his cultural, literary, philosophical and historical breadth but the technical depth of the paradigm studies on which the material is based.

The book consists of a collection of seven separate but related essays. The first essay is on letters, numbers, and more generally on signs in the context of Hegel, Gödel and Turing. The second is on Markov chains and the probabilistic analysis of text, a subject that bleeds naturally into cryptanalysis. This is a technically detailed piece that takes few hostages. The third essay features the Manchester Mark 1, provides an insightful treatment of the Williams tube and delay-line memory, the ergonomics and development of radar displays, and Christopher Strachey’s love-letter program that Link was instrumental in excavating and reconstructing.

The fourth essay, Enigma Rebus, is the signature essay of the volume. Link argues that computer-like devices, being intricate and opaque, soon become enigmas if not engaged with operationally, either by rebuilding them or by simulating them in software. Complex devices lapse into mystery, at least partially, within living memory, and Link suggests that instead of conventional historical investigation. it is perhaps archaeology that provides a more appropriate model in that ‘buried, incomplete, and often enigmatic artefacts’ are its stock in trade.

While each of the essays is self-contained they are unified by this central thesis: the indispensability of operational engagement to an understanding and preservation of complex historical computer-like devices. We find here the clearest articulation of Link’s overall thesis and it is the most heavyweight intellectual and methodological advocacy for restoration and reconstruction I have yet encountered.

In this fourth essay Link uses the beguiling device of Franz Kafka’s Odradek, a tantalising object trapped in the no man’s land between artefacts, which have use but no volition, and humans who have volition but have no purpose (see illustration). ‘The strange apparatus moves around autonomously, talks like a child, and occasionally laughs dryly’. Link goes on to explore the implications for obsolete artefacts through Thompson’s Theory of Rubbish, the idealisation of artefacts using electron tubes as the case study, the introduction of the ‘=’ sign in the 16th century, and what was learned from the reconstruction of Williams-tube memory that was not, and perhaps could not, otherwise be learned.

The remaining chapters cover technically detailed reconstructive descriptions of the Polish Bomba crypto machine, a 14th century algorithmic divination device, Strachey’s draughts program and the origin of the ENTER key and finally, a finely distilled survey of Turing’s software and hardware projects.

Given that the essays were written at different times for different readerships, the prior knowledge assumed across the volume is sometimes uneven as is the explanatory level.

This is an uncompromisingly serious book that provides a rich conceptual landscape with countless gems and insights to savour. Link is a substantial philosopher and technologist. His searching speculations capture rare resonances of meaning in our own historical efforts.

Kafka's Odrodek

50 Years ago .... From the Pages of Computer Weekly

Brian Aldous

Big machine for NATO coding: Tenders are now being examined by the Ministry of Defence for a large computer for a new centre to be opened in the late 1960s at Hullavington, in Wiltshire. The establishment will be known as the Defence Codification Data Centre and will deal with the classifying of items of NATO equipment. (CW011 p1)

D-I-Y Machine Cuts Costs: A Do-It-Yourself computer for teaching the theory and techniques of computing was demonstrated at the Trainex 66 exhibition in London last week. Assembled from standard logic elements, power supplies and mounting units supplied by Mel Equipment Co, it can cost as little as £200. (CW011 p7)

Retrieval system for real time inquiries: Real time inquiries for information are becoming increasingly a major concern for computer departments and to meet this need ICT have developed a general purpose retrieval system known as ICT 1900 FIND — File Interrogation of Nineteen hundred Data. (CW012 p1)

Hoover plans to create Data Bank: Around the 360/40 system, now undergoing trials at their Perivale, Middlesex, headquarters, Hoover plans to build up a data bank which will provide the company’s management with direct online access to information on all aspects of the firm’s production and stock position, and data on sales, personnel and purchasing across the country. (CW012 p12)

S-Two as multi-access control: The multi-access system planned at the Atlas Computer Laboratory, Chilton, Berkshire, will use an S-Two computer as console controller for the Atlas machine and a Data Products 16 million character disc store. The system will have 12 to 16 consoles in the laboratory and possibly others at remote locations. (CW013-014 p1)

Elliott System to aid Concorde Take-off: The two prototypes of the Concorde airliner will have a take-off director comprising an analogue computer supplied by Elliott Automation. Correlating eight variables, it will give the pilot a single reading to aid him during take-off and initial climb. (CW013-014 p1)

Lack of tools hits N/C project: A new threat to the development of numerical control software faces the National Engineering Laboratory at East Kilbride. It jeopardises an £800,000 investment in an American-built Univac 1108, and could lead to this country being dependent in advanced applications on American machine tools for many more years. (CW015 p1)

Leo 360 at new London boroughs’ EDP centre: A second computer centre has been opened in Hackney to be used by a consortium of the Hackney, Tower Hamlets and Harringay Boroughs of Greater London. It has an EELM Leo 360 computer which will initially han dle the financial work of the three boroughs. (CW015 p1)

Good start to new year for ICT: First orders announced by ICT for 1967 are worth £700,000 and stretch from London to Australia. At home a 1904 has been ordered by Sainsbury’s, the multiple grocers, and in Australia two 1903s are to go to a trading and property company, one of the largest in the country. (CW016 p1)

PDP 10 medium range launched: With the introduction of the PDP 10 range of computers the Digital Equipment Corporation is making a come-back in the medium sized machine market. First deliveries are expected next September according to Digital Equipment’s UK company at Reading. (CW016 p11)

NCC wins support of industry: Two months after membership conditions were announced last November, the National Computing Centre claims to represent the major part of the nation’s computer interests and reports that applications for membership continue to flow in. (CW017 p1)

Real Time Flight Tests on C-5A Freighter: An automatic data reduction station (ADRS) for the flight testing of the Lockheed C-5A military freighter will have both real-time and off-line operation modes, and PCM data word rates up to 250,000 words a second and digitised FM data word rates up to 55,000 a second. (CW017 p5)

First UK CDC 3300 goes into action — Engineers plan wide range of Operations: The first CDC 3300 computer in the UK went quietly into operation in London last week after an on-schedule delivery and installation at the Victoria offices of engineering consultants Freeman, Fox, Wilbur Smith and Associates. (CW017 p12)

Co-operation on ‘Mac’ project: A project to produce software for the EELM 4-75 multi-access system, to be installed at Edinburgh Regional Computing Centre in 1968, is under way at Edinburgh University. (CW018 p1)

Simulator System aids research into ATC: At an experimental centre to be inaugurated today, Thursday, at Bretigny airfield, 16 miles south-east of Paris, an air traffic control simulator based on a digital computer will be used for research into air traffic conditions over seven European countries. (CW018 p12)

SPL 1401 simulator for ICT 1900s: A Simulator which enables IBM 1401 programs to be run directly on ICT 1900 machines has been developed for ICT by Systems Programming Ltd. It will provide ICT with a valuable sales aid in the growing replacement market. (CW019 p1)

Elliott software cuts costs of automation: A practical solution to the problem of a comprehensive framework for the implementation of on-line industrial control systems has been achieved by Elliott-Automation. Their answer is APEX, a range of software that enables the control engineer to work directly from familiar instrument flow sheet data. (CW020 p1)

Biggest UK university machine: A joint computer centre, equipped with an IBM 360/67, is to be set up this year by the Universities of Newcastle upon Tyne and Durham. It will be the most powerful university centre in the UK and among the most advanced in the world. (CW021 p1)

Elliott System to guide EUROPA: Flight systems incorporating Elliott MCS 920M micro miniature digital computers will guide Europa, the international satellite launching rocket planned by the European Launcher Development Organisation. Seven MCS 920Ms are to be supplied initially. (CW021 p3)

Burroughs launch big machine in UK: A new large scale computer has entered the market in the UK with the introduction of the Burroughs B5500. This follows the successful launching in Britain less than a year ago of the medium size B2500-3500 Series. (CW021 p12)

Elliott-Automation Win Contract for Test System: A contract, worth nearly £1 million, has been awarded to Elliott-Automation for automated electronic test equipment, based on the 900 Series computer, for the RAF HS801 aircraft programme. (CW022 p1)

ICT 1902-1004 On-Line Link Up at Luton: The first ICT 1902 to be linked on and off line to a 1004 has been put into operation by Luton Corporation. The machine, which has 16K of store and six tape units, is linked via a 7201 data link which converts 1004 code to 1900 code. (CW022 p2)

French high speed OCR development: An optical character reader being developed at the data processing research laboratory of the Blaise Pascal Institute, Paris, is expected to be scanning print in varying sizes and styles at the rate of 5 to 10 cps by next March. (CW022 p5)

More power on 1900 processors: More power has been brought to ICT’s 1900 computers by the introduction of eight new central processors. Known as the E and F range, they are applicable to the 1904 to 1907 models, the F range incorporating a faster core store than the E range. (CW022 p12)

NPL research on DCN system: Work on the design of a digital communication network (DCN) to handle traffic for the real time, remote use of computers has been going ahead for a year at the National Physical Laboratory. (CW023 p1)

Elliott-Automation take over GEC computer company: The computer and automation subsidiary of the General Electric Co is to be taken over by Elliott-Automation. (CW023 p1)

Low-cost memory module: A high performance, low-cost memory module that could be adapted for most computers has been developed by Computer Technology Ltd, of Hemel Hempstead, the UK’s newest computer manufacturer. The module is claimed to have the same performance as similar American units. (CW023 p16)

Contact details

Readers wishing to contact the Editor may do so by email to
, or by post to 124 Stanley Road, Teddington, TW11 8TX.

Members who move house should notify Membership Secretary Dave Goodwin () of their new address to ensure that they continue to receive copies of Resurrection. Those who are also members of BCS, however, need only notify their change of address to BCS, separate notification to the CCS being unnecessary.

Queries about all other CCS matters should be addressed to the Secretary, Roger Johnson at , or by post to 9 Chipstead Park Close, Sevenoaks, TN13 2SJ.

North West Group contact details

Chairman  Tom Hinchliffe:  Tel: 01663 765040.
Secretary  Gordon Adshead  Tel: 01625 549770.

Forthcoming Events

London Seminar Programme

19nd Jan 2017 History of Enterprise Systems Geoff Sharman
16th Feb 2017 Simulation Models of Historical Computers - Atlas, MU5 and CDC 6600 Roland Ibbett
16th Mar 2017 Babbage and Lovelace Sydney Padua
20th Apr 2017 The ICT 1301 Rod Brown
18th May 2017 Lyons before LEO Neville Lyons

London meetings take place at the BCS in Southampton Street, Covent Garden starting at 14:30. Southampton Street is immediately south of (downhill from) Covent Garden market. The door can be found under an ornate Victorian clock.

You are strongly advised to use the BCS event booking service to reserve a place at CCS London seminars. Web links can be found at

For queries about London meetings please contact Roger Johnson at .

Manchester Seminar Programme

21th Jan 2017 A Search Through the Bins of Computer History David Eglin
17th Feb 2017 The History of the Semiconductor Revolution Steve Hill
21st Mar 2017 The History of ENIAC in Three Programs Mark Priestly

North West Group meetings take place in the conference room of the Royal Northern College of Music, Booth St East M13 9RD: 17:00 for 17:30.

For queries about Manchester meetings please contact Gordon Adshead at .

Details are subject to change. Members wishing to attend any meeting are advised to check the events page on the Society website at Details are also published in the events calendar at


MSI : Demonstrations of the replica Small-Scale Experimental Machine at the Museum of Science and Industry in Manchester are run every Tuesday, Wednesday, Thursday and Sunday between 12:00 and 14:00. Admission is free. See for more details

Bletchley Park : daily. Exhibition of wartime code-breaking equipment and procedures, including the replica Bombe, plus tours of the wartime buildings. Go to to check details of times, admission charges and special events.

The National Museum of Computing : Thursday, Saturday and Sunday from 13:00. Situated within Bletchley Park, the Museum covers the development of computing from the “rebuilt” Colossus codebreaking machine via the Harwell Dekatron (the world’s oldest working computer) to the present day. From ICL mainframes to hand-held computers. Note that there is a separate admission charge to TNMoC which is either standalone or can be combined with the charge for Bletchley Park. See for more details.

Science Museum : There is an excellent display of computing and mathematics machines on the second floor. The new Information Age gallery explores “Six Networks which Changed the World” and includes a CDC 6600 computer and its Russian equivalent, the BESM-6 as well as Pilot ACE, arguably the world’s third oldest surviving computer.

The new Mathematics Gallery has the Elliott 401 and the Julius Totaliser, both of which were the subject of CCS projects in years past, and much else besides.

Other galleries include displays of ICT card-sorters and Cray supercomputers. Admission is free. See for more details.

Other Museums : At can be found brief descriptions of various UK computing museums which may be of interest to members.

Committee of the Society

Chair  David Morriss FBCS CEng CITP:
Secretary  Dr Roger Johnson FBCS:
Treasurer  Dr David Hartley FBCS:
Chairman, North West Group   Prof. Tom Hinchliffe FBCS FIEE CEng:
Secretary, North West Group  Gordon Adshead MBCS:
Editor, Resurrection  Dik Leatherdale MBCS:
Website Editor  Dik Leatherdale MBCS:
Meetings Secretary  Kevin Murrell FBCS:
Membership Secretary  Dave Goodwin MBCS:
Media Officer  Dan Hayton MBCS FRSA:
Digital Archivist  Prof. Simon Lavington FBCS FIEE CEng:
Awards Sub-Committee Co-ordinator:  Peta Walmisley:

Awards Sub-Committee

Rachel Burnett, Roger Johnson, David Hartley

Museum Representatives
Science Museum  Haileigh Robertson:
National Museum of Computing  Victoria Alexander:
Bletchley Park Trust  Peronel Craddock:

Project Leaders
SSEM  Chris Burton CEng FIEE FBCS:
Bombe  John Harper Hon FBCS CEng MIEE:
Elliott 8/900 Series  Terry Froggatt CEng MBCS:
Software Conservation  Dr Dave Holdsworth CEng Hon FBCS:
Elliott 401 & ICT 1301  Rod Brown:
Harwell Dekatron Computer  Delwyn Holroyd:
Computer Heritage  Prof. Simon Lavington FBCS FIEE CEng:
ICL 2966/ICL 1900  Delwyn Holroyd:
Analytical Engine  Dr Doron Swade MBE FBCS:
EDSAC  Dr Andrew Herbert OBE FREng FBCS:
Bloodhound Missile/Argus  Peter Harry:
IBM Hursley Museum  Peter Short MBCS:

Co-opted Members
      Prof. Martin Campbell-Kelly FBCS CITP FLSW:
Past Chair  Rachel Burnett FBCS CITP Hon D. Tech:

science museum logo
MSI logo
TNMoC logo

Computer Conservation Society

Aims and objectives

The Computer Conservation Society (CCS) is a co-operative venture between BCS, The Chartered Institute for IT; the Science Museum of London; and the Museum of Science and Industry (MSI) in Manchester.

The CCS was constituted in September 1989 as a Specialist Group of the British Computer Society (BCS). It thus is covered by the Royal Charter and charitable status of BCS.

The aims of the CCS are to

  • To promote the conservation of historic computers and to identify existing computers which may need to be archived in the future
  • To develop awareness of the importance of historic computers
  • To develop expertise in the conservation and restoration of historic computers,
  • To represent the interests of Computer Conservation Society members with other bodies,
  • To promote the study of historic computers, their use and the history of the computer industry,
  • To publish information of relevance to these objectives for the information of Computer Conservation Society members and the wider public.

Membership is open to anyone interested in computer conservation and the history of computing.

The CCS is funded and supported by voluntary subscriptions from members, a grant from BCS, fees from corporate membership, donations, and by the free use of the facilities of our founding museums. Some charges may be made for publications and attendance at seminars and conferences.

There are a number of active Projects on specific computer restorations and early computer technologies and software. Younger people are especially encouraged to take part in order to achieve skills transfer.

The CCS also enjoys a close relationship with the National Museum of Computing.

Resurrection is the journal of the Computer Conservation Society.
Editor – Dik Leatherdale
Printed by – BCS, The Chartered Institute for IT
© Computer Conservation Society