 IBM 701 operator's console | |
| Also known as | Defense Calculator |
|---|---|
| Developer | Jerrier Haddad Nathaniel Rochester |
| Manufacturer | IBM |
| Released | 1952; 74 years ago (1952) |
| Introductory price | $12,000 a month rental charge / $15,000 a month per 40-hour shift |
| Units shipped | 19 |
| Memory | Total memory of 2048words of 36 bits each (72Williams tubes with a capacity of 1024bits each) |
| Successor | IBM 704 |
TheIBM 701 Electronic Data Processing Machine, known as theDefense Calculator while in development, wasIBM's first commercial scientific computer and its first series productionmainframe computer, which was announced to the public on May 21, 1952.[1] It was designed and developed byJerrier Haddad andNathaniel Rochester and was based on theIAS machine atPrinceton.[2][3][4]
The IBM 701 was the first computer in theIBM 700/7000 series, which were IBM's high-end computers until the arrival of theIBM System/360 in 1964.[5]
The business-oriented sibling of the 701 was theIBM 702 and a lower-cost general-purpose sibling was theIBM 650, which gained fame as the first mass-produced computer.[4][6]
IBM 701 competed with Remington Rand'sUNIVAC 1103 in the scientific computation market.[7] In early 1954, a committee of theJoint Chiefs of Staff requested that the two machines be compared for the purpose of using them for a Joint Numerical Weather Prediction project. Based on the trials, the two machines had comparable computational speed, with a slight advantage for IBM's machine, however when it came toinput/output the 701 was favored unanimously for its significantly faster input/output equipment.[8][9][10]
Nineteen IBM 701 systems were installed.[11] The first 701 was delivered to IBM's world headquarters in New York. Eight went to aircraft companies. At theLawrence Livermore National Laboratory, having an IBM 701 meant that scientists could run nuclear explosives computations faster.
"I think there is a world market for maybe five computers" is often attributed toThomas Watson Sr., chairman and CEO of IBM, in 1943. This misquote may stem from a statement by his son,Thomas Watson Jr. at the 1953 IBM annual stockholders' meeting. Watson Jr. was describing the market acceptance of the IBM 701 computer. Before production began, Watson visited with 20 companies that were potential customers. This is what he said at the stockholders' meeting, "as a result of our trip, on which we expected to get orders for five machines, we came home with orders for 18”.[12]
Aviation Week for 11 May 1953 says the 701 rental charge was about$12,000 (equivalent to $144,000 in 2025) per month;American Aviation 9 Nov 1953 says "$15,000 a month per 40-hour shift. A second 40-hour shift ups the rental to $20,000 a month".[citation needed]
The successor of the 701 was theindex register-equippedIBM 704, introduced 4 years after the 701. The 704 was not compatible with the 701, however, as the 704 increased the size of instructions from 18 bits to 36 bits to support the extra features. The 704 also marked the transition tomagnetic-core memory.
In 1952, IBM paired with language scholars fromGeorgetown University to develop translation software for use on computers. On January 7, 1954, the team developed an experimental software program that allowed the IBM 701 computer to translate from Russian to English. This was theGeorgetown–IBM experiment. The Mark 1 Translating Device, which was developed for the US Air Force, was able to produce its first automated Russian-to-English translation in 1959 and was shown to the public in 1964.[13]
In 1954, a group of scientists ran millions of simulated hands ofblackjack on an IBM 701 looking to determine the best playing decision for every combination of cards. The result of the study was the set of correct rules for hitting, standing, doubling or splitting in a blackjack game which are still the same today.[13]
The IBM 701 has a claim to be the first computer displaying the potential ofartificial intelligence inArthur Samuel'scheckers-playing program on February 24, 1956. The program, which was developed for play on the IBM 701, was demonstrated to the public on television. Self-proclaimed checkers master Robert Nealey played the game on an IBM 7094 computer in 1962 and the computer won. It is still considered a milestone for artificial intelligence and it offered the public during the early 1960s an example of the capabilities of an electronic computer.[14]
TheUniversity of California Radiation Laboratory at Livermore developed a language compilation and runtime system called theKOMPILER for their IBM 701.Speedcode was the firsthigh-level programming language created for anIBM computer.[15] The language was developed byJohn Backus in 1953 for the IBM 701 to support computation withfloating-point numbers. TheFortran compiler also developed by Backus was not released by IBM until theIBM 704.
The IBM 701 system[16] was composed of the following units:
The total weight (depending on configuration) was about 20,516 pounds (10.3 short tons; 9.3 t).[17]
The system usedvacuum tube logic circuitry and electrostatic storage, consisting of 72Williams tubes with a capacity of 1024bits each, giving a total memory of 2048words of 36 bits each. Each of the 72 Williams tubes was 3 inches in diameter. Memory could be expanded to a maximum of 4096 words of 36 bits by the addition of a second set of 72 Williams tubes or (later) by replacing the entire memory with magnetic-core memory. The Williams tube memory and later core memory each had a memory cycle time of 12 microseconds. The Williams tube memory required periodic refreshing, mandating the insertion ofrefresh cycles into the 701's timing. An addition operation required five 12-microsecond cycles, two of which were refresh cycles, while a multiplication or division operation required 38 cycles (456 microseconds). In addition, magnetic drum and magnetic tape were utilized for secondary storage.[18]
Instructions were 18bits long, single address.
Numbers were either 36 bits or 18 bits long,signed magnitude,fixed point. The full word has a precision of about ten decimal digits. A decimal digit corresponds to or 3.322 bits.
The IBM 701 had only two programmer accessible registers:
The Magnetic Drum Reader/Recorder was added on the recommendation ofJohn von Neumann, who said it would reduce the need for high speed I/O.[19]
The first magnetic tape drives were used on the Tape Processing Machine (TPM) and then adapted to the 701.[20]