The Computer Laboratory Relics Database

Uid:  Class:  calculating machine computer /part of documentation memory /part of network /part of other peripheral /part of
Name:  Machine:  ? CAP CDCS EDSAC I EDSAC II Elliot 405 Fairisle IBM 3420 IBM ? IBM? PDP11 Rainbow Ring Titan n/a other
18 matches found

Unique id/year of acquisition: CL-5/97
Name: EDSAC II chassis

Other No marked on object:
Inscription:
Dimensions: 690x180x95
Description:
Class: computer
Machine name: EDSAC II
Condition:
Notes: DW: Dates - used 1956-1965 - that sounds reasonable. This was one unit of the components of EDSAC 2. The machine was made of chassis like which may seem rather peculiar to modern eyes. There was a screw at one end and there was a turn knob at the other and these were physically forced into a plug and socket to make reliable contacts. Reliable contacts were a quite a problem in the days of this computer. The circuits were typically double triodes and the mode of operation was static rather than dynamic, in other words you could run the machine as slowly as you pleased rather than as in EDSAC 1 where you had a clock512 thousand cycles per second. This is one of the control chassis.It's a number 8 and this was used for individual control. The bulk of the machine consisted of 41 identical one bit parts of the arithmetic unit and the chassis for that were twice as long. There were other chassis like this which controlled one bit of the magnetic core memory and the form of construction is such that you can blow air through it sideways to keep it cool in contrast to the EDSAC 1 which relied on natural circulation of air round the valves. The valves are on the top. There were diodes as well, some valves are still in position. They are of slightly smaller size than those used for EDSAC 1 and underneath all the other components existed and air was blown to keep those parts cool.
Q: What was the design team for the second EDSAC?
DW: The design team consisted of probably Bill Renwick, Maurice Wilkes, myself and John Stringer plus technicians to help. It was a parallel computer as opposed to a serial computer and I think it was the first in England to use magnetic cores for memory and we co-operated with Mullard and they formed a production line for us and others, and so we initiated the production of ferrite cores in England.
Q: Was it built here in Cambridge?
DW: The entire machine was built in Cambridge. There were various other parts of it - it did in fact have what is now called a ROM of 768 words of 40 bits which catered for all simple needs and the store was originally 1024 words of 40 bits but it was extended during its life by the addition of 16000 words of 40 bits. Very small numbers by todays standards. A tape reader was developed for EDSAC 2 which is faster than the photo electric ones on EDSAC 1 which by then went about 40 characters a second (cross reference - the photo electric reader).
See also: CL-36/97
See also: CL-50/97
See also: CL-68/99

Unique id/year of acquisition: CL-17/97
Name: Paper tape reader

Other No marked on object: none
Inscription: none
Dimensions: 261x155x205
Description: Paper tape reader, 1000 characters per second. Silver-grey metal casing with the top open (missing ?). The front has the reading mechanism, which includes a roller attached to a large motor inside, a clear plastic lens, the reader itself and a plastic channel through which the tape would be fed. A lever on the side is depressed to operate the machine. Inside is the motor, made by the Sun Electrical Co. Ltd.,London, and operating at 1400 rpm at 200 Volts. The opposite end of the motor is attached to a fan which sucks air in through a circular grid in the rear. Also inside is a light bulb made by (?) British Pre-focus. Together with the grill, there are two circular multi-pin sockets in the rear, one male, one female. The outer casing is scratched and rusty and coming apart. Rear sockets appear badly corroded.
Class: peripheral
Machine name: EDSAC II
Condition: fair
Notes: DW: This is a tape reader, photo-electric type which was developed at the Computer Laboratory, to read in paper tape at a thousand characters a second with the ability to stop on a single character. It is a very simple construction. It has a motor which revolves a cylinder which is pressed against the tape and it pulls it forward - there is a brake which is actuated by electro magnet underneath and is strong enough to stop the tape in spite of the rotor pulling it forwards. This is only capable of reading a 5-hole tape unlike the others which were developed from this by Elliots and the Engineering workshop. This is a lamp - it's reflected here down onto the tape. There are photo-cells underneath and there is a mechanism on the right so the tape can be loaded sideways and there is an essential button on the top which allows the tape to be ejected at full speed without being read. These were in use for many years.
Q:What machine were they first and last used with?
DW: They were first used with EDSAC 2 and Elliots supplied them to a fair number of other computers throughout the UK and abroad, and when they were last used I'm not sure. This was made about 1957 but was in use probably until the 70's or 80's.
See also: CL-7/97
See also: CL-71/99

Unique id/year of acquisition: CL-36/97
Name: EDSAC II chassis

Other No marked on object: 2(label)
Inscription: "EDSAC II CHASSIS 2 No 12" on front
Dimensions: 1000(approx)x180x94
Description: Grey metal rack. Upper section with space for 60 "Brimar" or "Mullard" glass valves, not all identical, many missing. Lower section with components, resistors etc. Front painted red, with handle connected to rod running whole length terminating in large screw at rear. Rear has large number of sockets.
Class: computer
Machine name: EDSAC II
Condition: poor
Notes: DW:This rather bulky unit is one big part of the arithmetic unit of EDSAC 2. It contains about six one bit register and adder, a complimenter, and connections to the rest of the machines. The arithmetic unit was made of 41 identical units and a typical register would consist of one double triode each gating unit to it took another double triode and there is a double row of valves along the top. The components are underneath, the unit was cooled by a sideways airflow and this allowed for easy maintenance because if a unit failed it could be replaced by screwing and unscrewing this rather large screw at the end and this big socket or plug at the far end. In those days it was exceedingly important to have reliable contacts on plugs and sockets. These were quite good partly due to the fact that they were positioned exactly by the screw and forcibly forced in.
Q:This was made here in the Lab - is that right?
DW:This was made here in the Lab - I have forgotten how many we made - there's 41 in the machine and probably 2 or 3 spares and this was the bulk of the computer. This is one bit of the arithmetic unit. I think that was one of the bits that control possibly for magnetic tape or various other miscellaneous functions. All the machine plugged in unlike the original EDSAC, which only the valves plugged in otherwise the chassis were wired in permanently but this did allow for ease of maintenance.
See also: CL-5/97
See also: CL-50/97
See also: CL-68/99

Unique id/year of acquisition: CL-43/97
Name: Engineer Control Panel

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: computer
Machine name: EDSAC II
Condition:
Notes: DW:This is the Engineers control panel for the EDSAC 2. It allowed you to run the computer, it allowed you to do single orders, it allowed you to do single microsteps, it was the back of the machine and indicator lights enabled you to trace the course of the register transfers or computation. There was a variable speed on it, adjustable loudspeaker and various indicators.

Unique id/year of acquisition: CL-50/97
Name: EDSAC II chassis

Other No marked on object:
Inscription:
Dimensions: 690x180x95
Description:
Class: computer
Machine name: EDSAC II
Condition:
Notes: DW:This is one of the chassis of EDSAC 2. It is one of the shorter chassis. The construction can be seen, it consists of a number of valves, underneath there are the components mounted on boards. The air is blown through sideways in order to keep it cool. There is a very long twist rod which allows the plugs to be firmly inserted in the sockets. In these days contact problems were not unknown and this device ensured a firm contact for these components.
See also: CL-5/97
See also: CL-36/97
See also: CL-68/99

Unique id/year of acquisition: CL-51/97
Name: Magnetic tape holder

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: memory
Machine name: EDSAC II
Condition:
Notes: DW:This is a magnetic tape holder for the EDSAC 2. We had in fact one inch magnetic tape and these were held on reels. The DECCA device was developed in the Lab but manufactured by DECCA. They had magnetic reels and one of the interesting aspects of the magnetic tape system was that the heads ran out of contact with the tape, resulting in theory in indefinite life but less resolution. The tapes were stored in these boxes to prevent magnetic influence affecting the tapes. This particular reel originally had the autocode compiler for the EDSAC 2. This was certainly before the days when magnetic tape was used very extensively.
See also: CL-12/97
See also: CL-79/99
See also: CL-117/99

Unique id/year of acquisition: CL-51/97
Name: Magnetic tape holder

Group id: 2
Other No marked on object:
Inscription:
Dimensions:
Description:
Class: memory
Machine name: EDSAC II
Condition:
Notes: DW:This is a magnetic tape holder for the EDSAC 2. We had in fact one inch magnetic tape and these were held on reels. The DECCA device was developed in the Lab but manufactured by DECCA. They had magnetic reels and one of the interesting aspects of the magnetic tape system was that the heads ran out of contact with the tape, resulting in theory in indefinite life but less resolution. The tapes were stored in these boxes to prevent magnetic influence affecting the tapes. This particular reel originally had the autocode compiler for the EDSAC 2. This was certainly before the days when magnetic tape was used very extensively.
See also: CL-12/97
See also: CL-79/99
See also: CL-117/99

Unique id/year of acquisition: CL-60/97
Name: Paper listing of autocode compiler

Other No marked on object: 63
Inscription: Autocode translator
Dimensions: 220x60x60
Description: Roll of paper, print inside very faded.
Class: other
Machine name: EDSAC II
Condition: poor
Notes: DW:This roll of paper claims that it's the auto code compiler for the EDSAC 2. In a very faded condition - you can just read the instructions on the auto code compiler on the left. It's not very annotated or titled but it was a relatively long programme as you can see by the length of the roll. This is a typical typing space. The autocode compiler was written by David Hartley, probably about 1957 or 1958 and it enabled an autocode to be used on the EDSAC 2 which enabled you to use Algebraic expressions instead of a simple list of instructions. A form of this was transferred to Titan and many people believed this was an easier way to program than use direct machine code. You'll notice from the way I express this that I did not. (Correction by David Hartley - it was written in 1960-61.)

Unique id/year of acquisition: CL-61/97
Name: Creed tape perforator

Other No marked on object: serial no 4363, others mostly unreadable
Inscription: Creed
Dimensions: 570x410x340
Description: Grey metal case. Keyboard at front, mechanical typewriter-like with numbers and letters only (QWERTY layout). 5-hole paper tape held in feed unit at top, hinged on right. Output unit on left side, complicated arrangement of levers and cogs. Switch (power ?) on right front. motor unit at rear. 4 rubber feet on base. Cable extending from rear right.
Class: peripheral
Machine name: EDSAC II
Condition: fair
Notes: DW: This is a keyboard perforator made by Creed. Normally one operates the keyboard and produces a paper tape from this roll with up to 5 holes punched across the tape. This was used as a fast output for EDSAC 1 and EDSAC 2. There were extra solenoids put in which could actuate the punches and it ran at about 35 characters to the second. According to the label this is one of those connected to EDSAC 2 and the EDSAC 2 had two alternative outputs for paper tape. This is labelled A or it might actually have been used in the tape preparation room for copying tapes, so that is another use of these keyboard perforators. But these were the dominant output device for EDSAC 1 and EDSAC 2 for most of the time. Eventually they were replaced by a high speed Creed punch and teletype 110 characters a second punch.
See also: CL-72/99

Unique id/year of acquisition: CL-67/99
Name: EDSAC II user control panel

Other No marked on object: none
Inscription: none
Dimensions: 460x455x320
Description: Triangular cross-section,long edge vertical. Sides and back of grey metal, front of brown plastic. Rubber feet. Back has 7 large sockets at bottom, bulge at top. Left side has exposed wiring. Front has many knobs, dials, lights and buttons, many with legends, some of which are stuck on, some inscibed in plastic. Faded label at top states "Save time trouble, money and labour, make more use of your computer or tabulator".
Class: computer
Machine name: EDSAC II
Condition: good
Notes: Interrupt facility, could only respond to one, a later add-on. Punch error added for Creed which failed often. Blank tape - ran through blank. Vol knob for loudspeaker. 3 buttons in bottom left all that were used.

Unique id/year of acquisition: CL-68/99
Name: EDSAC II chassis

Other No marked on object: none
Inscription: EDSAC II CHASSIS 7 No 10 (printed on front), 22/7/65 (handwritten on front),Serviceable 22/7/65 PJB (handwritten on label on top)
Dimensions: 690x180x95
Description: Grey metal rack. Upper section with space for 36 glass valves, not all identical, several missing. Lower section with components, resistors etc. Front painted black, with handle connected to rod running whole length terminating in large screw at rear. Rear has large number of sockets.
Class: computer
Machine name: EDSAC II
Condition: good
Notes: EDSAC II was made of a number of such plug-in units, the modular construction allowing easy maintenance. The bulk of the machine consisted of 41 identical long chassis, each of which was one part of the arithmetic unit and contained six one bit registers, an adder, a complimenter, and connections to the rest of the machine. There were other shorter chassis each of which controlled one bit of the magnetic core memory. The form of construction is such that air could be blown through sideways to keep the components cool (in contrast to the EDSAC I which relied on natural circulation of air round the valves). The screw at one end and turn knob at the other were used to physically force a plug into a socket to make reliable contacts.
See also: CL-5/97
See also: CL-36/97
See also: CL-50/97

Unique id/year of acquisition: CL-68/99
Name: EDSAC II chassis

Group id: 2
Other No marked on object: none
Inscription: EDSAC II CHASSIS 7 No 7 (printed on front), other labels but too faded to read.
Dimensions: 690x180x95
Description: Grey metal rack. Upper section with space for 36 glass valves, not all identical, several missing. Lower section with components, resistors etc. Front painted black, with handle connected to rod running whole length terminating in large screw at rear. Rear has large number of sockets.
Class: computer
Machine name: EDSAC II
Condition: poor, rusty
Notes: EDSAC II was made of a number of such plug-in units, the modular construction allowing easy maintenance. The bulk of the machine consisted of 41 identical long chassis, each of which was one part of the arithmetic unit and contained six one bit registers, an adder, a complimenter, and connections to the rest of the machine. There were other shorter chassis each of which controlled one bit of the magnetic core memory. The form of construction is such that air could be blown through sideways to keep the components cool (in contrast to the EDSAC I which relied on natural circulation of air round the valves). The screw at one end and turn knob at the other were used to physically force a plug into a socket to make reliable contacts.
See also: CL-5/97
See also: CL-36/97
See also: CL-50/97

Unique id/year of acquisition: CL-69/99
Name: EDSAC II Control matrix

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: computer
Machine name: EDSAC II
Condition:
Notes: The control matrix housed the ferrite cores which stored the microprogramme for EDSAC II. This plastic housing contained 16 13mm cores and associated wiring, 64 such units were needed (in an 8 x 8 flat array), making 1024 cores in all. Smaller core memories were used in other parts of EDSAC II.
See also: CL-70/99

Unique id/year of acquisition: CL-70/99
Name: EDSAC II production moulds

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: other
Machine name: EDSAC II
Condition:
Notes: The control matrix housed the ferrite cores which stored the microprogramme for EDSAC II. This plastic housing contained 16 13mm cores and associated wiring, 64 such units were needed (in an 8 x 8 flat array), making 1024 cores in all. Smaller core memories were used in other parts of EDSAC II.
See also: CL-69/99

Unique id/year of acquisition: CL-71/99
Name: Elliot tape reader \& bench

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: peripheral
Machine name: EDSAC II
Condition:
Notes:
See also: CL-7/97
See also: CL-17/97

Unique id/year of acquisition: CL-72/99
Name: Creed paper tape punch

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: peripheral
Machine name: EDSAC II
Condition:
Notes: Two Creed High speed paper tape punches were connected to EDSAC II in about 1962. They ran at the amazing speed of 300 rows per second. They had a tendency to jam and had to be taken to pieces to undo the jam causing a considerable maintenance problem. Eventually they were replaced by Teletype punches operating reliably at 110 rows per second.
See also: CL-61/97

Unique id/year of acquisition: CL-97/99
Name: EDSAC II user identifier

Other No marked on object:
Inscription:
Dimensions:
Description:
Class: other
Machine name: EDSAC II
Condition:
Notes: This was a simple home made device attached to the wall near the EDSAC console, by an alcove also containing a large red sofa and a mass of reading material - largely science fiction - for users whiling away the time until their turn during the night hours. Users fed their identifier into the top of the queue device so it entered the displayed waiting sequence and reclaimed it from the bottom after their turn (from Dr Lucy Slater, June 1999).

Unique id/year of acquisition: CL-123/99
Name: EDSAC II Engineers' Display Panel

Other No marked on object:
Inscription: numbers (0 - 39) and letters (XCHM+FELKDuq+prwst)
Dimensions: 605x400x110
Description: Plastic panel with many holes, most with small lamp, mounted on metal frame. Some connections at back and quite a lot of wiring still connected.
Class: computer
Machine name: EDSAC II
Condition: fair
Notes:

Notes

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