The EDVAC is the successor of the ENIAC. Made by the same designers: Mauchly and Eckert.
This computer was called by acronym EDVAC (Electronic Discrete Variable Automatic Computer) and its public presentation was carried through in 1947
This machine should be abel to hold any programme in memory that was fed to it. This would be possible because EDVAC was going to have more internal memory than any other computing device to date. In other words a multipurpose computer.
The idea being that given a tube of mercury, an electronic pulse could be bounced back and forth to be retrieved at will--another two state device for storing 0s and 1s. This on/off switchability for the memory was required because EDVAC was to use binary rather than decimal numbers, thus simplifying the construction of the arithmetic units.
SpecificationsPROGRAMMING AND NUMERICAL SYSTEM
Internal number system Binary Binary digits per word 44 Binary digits per instruction 4 bits/command 10 bits each address Instruction per word 1 Instructions decoded 16 Instruction used 12 Arithmetic system Floating and Fixed point Instruction type Four-address code
EDVAC Floating Point (U.S. Army Photo)Number range
-(1-2^-43) less than or equal to n less than or equal to (1-2^-43)
-(1-2^-33)2^511 less than or equal to n less than or equal to (1-2^-33)2^511
The fractional part of floating point number has 33 bits plus sign, and the exponent of 2 may range from -512 to +511.Instruction word format
Alpha-Add Beta-Add Gamma-Add Delta-Add Order 1-10 11-20 21-30 31-40 41-44ARITHMETIC UNIT
Microsec Add time (includ. stor. access) 864 (min 192 max 1,536) Mult time (includ. stor. access) 2,880 (min 2,208 max 3,552) Div time (includ. stor. access) 2,930 (min 2,256 max 3,600) Construction Vacuum-tubes and Diode-gates Number of rapid access word registers 4 Basic pulse repetition rate 1.0 megacycle/sec Arithmetic mode Serial Timing Synchronous Operation SequentialSTORAGE
Number of Number of Media Words Digits Access Microsec Mercury A.D.L. 1,024 48-384 48-384 Magnetic Drum 4,608 48/Word 17,000 Includes relay hunting and closure. The rate of information transfer to and from the drum is at one megacycle per second. The block length is optional from 1 to 384 words per transfer instruction. Magnetic tape 48/Word Maximum number of units that can be connected to the system 7 Units Maximum number of characters per linear inch of tape 112 Char/inch Channels or tracks on the tape 8 Track/tape Blank tape separating each record 1.5 Inches Tape speed 75 Inches/sec Start time 3 Milliseconds Stop time 3 Milliseconds Average time for experienced operator to change reel of tape 30 Seconds Physical properties of tape Width 5/8 Inches Length of reel 1,250/2,500 Feet Composition Red Oxide
The magnetic tape system has the following features: Variable block length from 2 to 1,024 words. The search order releases the machine for computation during search. Information which has been taken from a block and operated upon, can be automatically re-recorded in the same block.INPUT
Media Speed Photoelectric Tape Reader 942 sexadec char/sec 78 words/sec Card Reader (IBM) 146 cards/min 8 words/cardOUTPUT
Media Speed Paper Tape Perf. 6 sexadec char/sec 30 words/min Teletypewriter 6 sexadec char/sec 30 words/min Card Punch 125 cards/min 1,000 words/minCIRCUIT ELEMENTS OF ENTIRE SYSTEM
Type Quantity Type Quantity Tubes, total 5,937 6Y6 1,000 6AN5 275 6J6 1,500 2D21 160 6AG7 1,127 6SN7 150 6V6 900 6AS6 50 6L6 275 Misc 500 Diodes, total 12,000 1N297 6,000 Misc 1,200 1N 34 4,800 Transistors, total 328 2N398 256 2N123 4 2N1008B 60 2N167 4 2N 43 4
1947 first issue
|Last Updated on October 11, 2002||For suggestions please mail the editors|
Footnotes & References
|1||History of Computing EDVAC.htm|
|2||www.upenn.edu\Penn Special Collections-Mauchly Exhibition 9.htm|
|3||Electronic Computers Within The Ordnance Corps, Appendix II -- EDVAC.htm|