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Successor to ENIAC
EDVAC
(Electronic Discrete Variable Automatic
Computer)
From EDVAC paper, Wikipedia, and U.Penn Moore School web sites
Wiki’s story
• ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944, and design work for the EDVAC commenced before the ENIAC was fully operational. • The design would implement a number of important architectural and logical improvements conceived during the ENIAC's construction and would incorporate a high‐speed serial‐access memory.[1]
• Like the ENIAC, the EDVAC was built for the U.S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania'sMoore School of Electrical Engineering. • Eckert and Mauchly and the other ENIAC designers were joined by John von Neumann in a consulting role; von Neumann summarized and discussed logical design developments in the 1945 First Draft of a Report on the EDVAC.[2]
• One of the earliest electronic computers.
– There is still controversy
– ENIAC not programmable
• Eckert and Mauchly at Penn
– Unlike its predecessor
• It was binary rather than decimal and
• It was “the first” stored program digital computer
From the More School (Penn)
• By the Spring of 1944 it was clear to many people who had been working on the ENIAC that there were ways to improve its method of operation. • Simplify the process of programming and wiring the machine. – Realizing this fact well before the ENIAC was operational, Mauchly, Eckert, and other members of the project were already thinking of mechanisms that would simplify programming procedures in a new machine.
– They included the idea of storing programs within some special mechanism. The prospects of building this improved machine materialized when the Bureau of Ordnance issued a follow‐on contract for the EDVAC computer.
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• It was the highly skilled mathematician, John von Neumann, who produced the best formal description of a stored program computer. • During the fall of 1944 von Neumann took time off from his work at the Institute for Advanced Studies in Princeton, New Jersey and the Los Alamos Project to take part in the Moore School discussions regarding the EDVAC design. • No official reports or minutes came out of these joint discussions, making issues of credit very difficult to resolve. Instead, Von Neumann independently drafted a report titled the "First Draft Report of the Edvac
Design." As a draft document merely reflecting his current thoughts, von Neumann had not attempted to attribute or resolve issues of credit. • Herman Goldstine had given the document wide circulation, which had the unfortunate (or fortunate) result of placing the knowledge in the public domain.
• The controversy here reflects, in part, the different cultures of electrical engineers and mathematicians. • Whereas electrical engineers tend not to publish their ideas before they turn them into concrete inventions, mathematicians often circulate their ideas amongst colleagues even before they are ready to release them in a publication. • Both sides failed to appreciate the different conventions of their respective fields, fueling the priority disputes that ensued.
EDVAC Design
Technical description (wiki)
• Binary serial computer with addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory[1] capacity of 1,000 44‐bit words (later set to 1,024 words, thus giving a memory, in modern terms, of 5.5 kilobytes).
• Physically, the computer comprised the following components:
– a magnetic tape /wire reader‐recorder (R)
– a control unit with an oscilloscope and timer (CC)
– a dispatcher unit to receive instructions from the control and memory
– a computational unit to perform arithmetic operations with results to memory after checking on a duplicate unit (CA)
– a dual memory unit consisting of two sets of 64 mercury acoustic
delay lines of eight words capacity on each line (M)
– three temporary tanks each holding a single word[1]
http://www.library.upenn.edu/exhibits/rbm/mauchly/img/9edvdia.jpg
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Speed and Operation
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Realization
EDVAC's addition time was 864 microseconds (about 1.16 kHz) and its multiplication time was 2900 microseconds (about 0.38 kHz).
The computer had almost 6,000 vacuum tubes and 12,000 diodes, and consumed 56 kW of power. It covered 490 ft² (45.5 m²) of floor space and weighed 17,300 lb
(7,850 kg). The full complement of operating personnel was thirty people per eight‐hour shift.
EDVAC was delivered to the Ballistics Research Laboratory in August 1949. and began operation in 1951. Its completion was delayed because of a dispute over patent rights between Eckert and Mauchly and the University of Pennsylvania, resulting in Eckert and Mauchly's
resignation and departure to form the Eckert–Mauchly Computer Corporation and taking most of the senior engineers with them. (Now Unisys)
By 1960 EDVAC was running over 20 hours a day with error‐free run time averaging eight hours. EDVAC received a number of upgrades including punch‐
card I/O in 1953, extra memory in slower magnetic drum form in 1954, and a floating point arithmetic unit in 1958.
EDVAC ran until 1961
http://www.library.upenn.edu/exhibits/rbm/mauchly/jwm9.html
http://upload.wikimedia.org/wikipedia/commons/1/17/Edvac.jpg
2.0 MAIN SUBDIVISIONS OF THE SYSTEM
1.0 DEFINITIONS
• Very high speed automatic digital computing system which can carry out instructions to perform calculations of a considerable order of complexity
• Instructions which govern operation and numeric values given in some form which the device can sense: –
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Punched into a system of punch cards
Teletype tape, Magnetically impressed on steel tape or wire
Photographically impressed on motion picture film
Wired into one or more fixed or exchangeable plugboards
• All these procedures require the use of some code to express the logical and the algebraical definition of the problem under consideration, as well as the necessary numerical material
• It must be able to carry them out completely and without any need for further intelligent human intervention.
• The device may recognize the most frequent malfunctions automatically. It might even carry out the necessary correction automatically and continue
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First: Since the device is primarily a computer, it will have to perform the elementary operations of arithmetics (CA)
Second: The logical control of the device, that is the proper sequencing of its operations can be most efficiently carried out by a central control organ. (CC)
Third: Any device which is to carry out long and complicated sequences of operations (specifically of calculations) must have a considerable memory for intermediate results, instructions, tables etc. (M) – It is nevertheless tempting to treat the entire memory as one organ, and to have its parts even as interchangeable as possible for the various functions enumerated above.
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Fourth: The device must have organs to transfer (numerical or other) information from R into its specific parts, C and M. These organs form its input, the fourth specific part: (I)
Fifth: The device must have organs to transfer (presumably only numerical information) from its specific parts C and M into R. These organs form its output, part: (O)
All existing (fully or partially automatic) computing devices use (R) as a stack of punch‐cards or a length of teletype tape for these purposes.
– Long term external vs short term internal memory
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4.0 ELEMENTS, SYNCHRONISM, NEURON ANALOGY
• Every digital computing device contains certain relay like elements, with discrete equilibria.
– Such an element has two or more distinct states in which it can exist indefinitely. – One type remains in state without any outside support – Other depends for its existence upon the presence of an outside stimulus.
• The emitted stimuli must be of the same kind as the received one
– They must be able to stimulate other elements. – There must, however, be no energy relation between the received and the emitted stimuli, that is, an element which has received one stimulus, must be able to emit several of the same intensity. In other words: Being a relay, the element must receive its energy supply from another source than the incoming stimulus.
• Any such device may time itself autonomously. Alternatively, they may have their timing impressed by a fixed clock.
6.0 E‐ELEMENTS
• The ideal procedure would be to treat the elements as vacuum tubes.
– But, need a detailed analysis of specific questions at early stage of the discussion. To avoid this we will use a hypothetical element, which functions essentially like a vacuum tube.
• E – element, like a logic gate with delay and possibly inverting inputs. • Clock pulses which “frame” data 5.0 PRINCIPLES GOVERNING THE ARITHMETICAL OPERATIONS
• Tubes are used as gates to handle numbers by means of their digits, it is natural to use a system of arithmetic in which the digits are also two valued. This suggests the use of the binary system.
• A consistent use of the binary system is also likely to simplify the operations of multiplication and division considerably.
• “Telescoping” scheme (adder trees) due to H. Aiken is not a good idea for vacuum tubes. 7.0‐10.0 CIRCUITS FOR THE ARITHMETICAL OPERATIONS
• Bit Serial operations. – Tubes are expensive, prone to failure, and unbelievably fast.
– Delay lines for shift registers • 30 ‐ 32 bit words
• Block diagrams from networks of E‐elements • Need Add, Subtract, Multiply. Rest can be done with table lookup and interpolation
• Binary point for fixed point (fractional) operations 4
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11.0 ORGANIZATION OF CA. COMPLETE LIST OF OPERATIONS
• Every number coming from M into CA is routed into Ica. At the same time the number previously in Ica is moved on to Jca, and the number previously in Jca is cleared.
• Another operation is the need to sense the sign of a number, or the relation between two numbers, and choose accordingly between two alternative actions.
• 10 operations of CA:
• +, ‐, *, /, sqrt, (move) i, (move) j, (select) s, dec‐bin, bin‐dec
14 CC AND M
• Function of CC is to receive orders, to interpret them, and then either to carry them out, or to stimulate properly those organs which will carry them out.
– List of the orders which control the device
– Define the mathematical and logical meaning and the operational significance of the code words.
• Orders come from M, the same place where the numerical material is stored. Four types:
– Instruct CA to carry out one of its ten operations
– Transfer of number from one place to another
– Transfer its own connection with M to a different point in M, with the purpose of getting its next order from there (jump)
– Input and the output
12/13 CAPACITY ORGANIZATION OF THE MEMORY M
• Delay Line memories for arithmetic
• 30 (32) bit memories for words
– Need to store tables for interpolation
– Need to store lots of data for numerical calculations (numerical solutions to pde’s)
– Need at least 64K (bits) prefer 256K
• Lots of delay line memories
• Iconoscope Memory (charge storage)
Jumps
• In principle CC should be instructed, after each order, where to find the next order that it is to carry out. – This is undesirable, it should be reserved for exceptional occasions, while as a normal routine CC should obey the orders in the temporal sequence in which they naturally appear in memory
– Two types of Jumps – JSR and Jump
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15.0 THE CODE
Most/Least significant bit is used to define numbers vs op‐codes
Consider putting several such orders into one minor cycle. γ number or load immediate value
α didactic operation of CA (w = codes 0‐9)
– C (clear acc, after result, h(old)) – (ε)Store Imm, (δ)Store (to address μ,ρ), (θ) Store to Ica, none ‐> hold
• β Load (from address μ,ρ)
• Ϛ Jump (to address μ,ρ)
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• Details have changed between two papers…
• Last Remark allows for self‐modifying code (addresses). From Burks, Goldstein, von Neumann D‐Wave Quantum Computer Hardware
http://www.dwavesys.com/en/dw_homepage.html
Quantum Computing: The next big thing?
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CNT Computer
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