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- ----------------------------------------------------
- A Chronology of Digital Computing Machines (to 1952)
- ----------------------------------------------------
-
- I thought this material would be of interest to this group, considering
- the recent discussions of early computers. I have compiled it from two
- sources. The primary one that I used is:
-
- Bit by Bit: An Illustrated History of Computers.
- By Stan Augarten, pub. 1984 by Ticknor and Fields, New York.
- ISBN 0-89919-268-8, 0-89919-302-1 paperback.
-
- I recommend that book, by the way, but with some reservations. The author
- is a journalist rather than a computer person. From time to time this shows,
- but it's generally clear what he means even if he doesn't actually say that.
- In any case, he does tell the story in an interesting and readable fashion.
-
- For some material in the last part of the chronology I also consulted:
-
- Encyclopedia of Computer Science and Engineering, 2nd edition.
- Editor Anthony Ralston, Associate Editor Edwin D. Reilly Jr.,
- pub. 1983 by Van Nostrand Reinhold, New York. ISBN 0-442-24496-7.
-
- The criteria for including a machine in this chronology were that it either
- was technologically innovative or was well known and influential; certain
- particularly innovative inventions have also been included as of the first
- time that they were described. When I refer to a machine as being able to do
- some operation, I mean that it can do it more or less without assistance from
- the user. This disqualifies the abacus from consideration, for instance;
- similarly, a user wanting to subtract 16 on a 6-digit Pascaline could do it
- by adding 99984, but this does not count as ability to do subtraction.
-
- Where I do not describe the size of a machine, it is generally suitable for
- desktop use if it has no memory and is unprogrammable, or is a small
- prototype, but would fill a small room if it has memory or significant
- programmability (of course, the two tend to go together).
-
- The names Tuebingen, Wuerttemberg, and Mueller should have an umlauted
- "u" in place of the "ue" used here.
-
- ----------------------------------------------------
-
- 1623. Wilhelm Schickard (1592-1635), of Tuebingen, Wuerttemberg (now in
- Germany), makes his "Calculating Clock". This is a 6-digit
- machine that can add and subtract, and perhaps includes an overflow
- indicator bell. Mounted on the machine is a set of Napier's Rods, a
- memory aid facilitating multiplications. The machine and plans are lost
- and forgotten in the war that is going on. (The plans were rediscovered
- in 1935, lost again in the war, and re-rediscovered by the same man in 1956!
- The machine was reconstructed in 1960 and found to be workable.)
- Schickard was a friend of the astronomer Kepler.
-
- 1644-5. Blaise Pascal (1623-1662), of Paris, makes his "Pascaline". This
- 5-digit machine can only add, and that probably not as reliably as
- Schickard's, but at least it doesn't get forgotten -- it establishes the
- computing machine concept in the intellectual community. (Pascal sold about
- 10-15 of the machines, some supporting as many as 8 digits, and a number of
- pirated copies were also sold. No patents...)
- This is the same Pascal who invented the bus.
-
- 1674. Gottfriend Wilhelm von Leibniz (1646-1716), of Leipzig, makes his
- "Stepped Reckoner". This uses a movable carriage so that it can
- multiply, with operands of up to 5 and 12 digits and a product of up to 16.
- But its carry mechanism requires user intervention and doesn't really work
- in all cases anyway. The calculator is powered by a crank.
- This is the same Leibniz or Leibnitz who co-invented calculus.
-
- 1775. Charles, the third Earl Stanhope, of England, makes a successful
- multiplying calculator similar to Leibniz's.
-
- 1770-6. Mathieus Hahn, somewhere in what is now Germany, also makes a
- successful multiplying calculator.
-
- 1786. J. H. Mueller, of the Hessian army, conceives the idea of what came
- to be called a "difference engine". That's a special-purpose calcu-
- lator for tabulating values of a polynomial, given the differences between
- certain values so that the polynomial is uniquely specified; it's useful
- for any function that can be approximated by a polynomial over suitable int-
- ervals. Mueller's attempt to raise funds fails and the project is forgotten.
-
- 1820. Charles Xavier Thomas de Colmar (1785-1870), of France, makes his
- "Arithmometer", the first mass-produced calculator.
-
- 1822. Charles Babbage (1792-1871), of London, having reinvented the differ-
- ence engine, begins his (government-funded) project to build one by
- constructing a 6-digit calculator using similar geared technology.
-
- 1832. Babbage produces a prototype segment of his difference engine,
- which operates on 6-digit numbers and 2nd-order differences (i.e.
- can tabulate quadratic polynomials). The complete engine was to have
- operated on 20-digit numbers and 6th-order difference, but no more than
- this prototype piece was ever assembled.
-
- 1834. Pehr George Scheutz, Stockholm, produces a small difference engine
- in wood, after reading a brief description of Babbage's project.
-
- 1836. Babbage produces the first design for his "Analytical Engine".
- Whether this machine, if built, would have been a computer or not
- depends on how you define "computer". It lacked the "stored-program"
- concept necessary for implementing a compiler; the program was in read-only
- memory, specifically in the form of punch cards. In this article such a
- machine will be called a "program-controlled calculator".
- The final design had three punch card readers for programs and data.
- The memory had 50 40-digit words of memory and 2 accumulators. Its program-
- mability included the conditional-jump concept. It also included a form of
- microcoding: the meaning of instructions depended on the positioning of
- metal studs in a slotted barrel. It would have done an addition in
- 3 seconds and a multiplication or division in 2-4 minutes.
-
- 1842. Babbage's difference engine project is officially cancelled.
- (Babbage was spending too much time on the Analytical Engine.)
-
- 1843. Scheutz and his son Edvard Scheutz produce a 3rd-order difference
- engine with printer, and the Swedish government agrees to fund
- their next development.
-
- 1853. To Babbage's delight, Scheutz and Scheutz complete the first really
- useful difference engine, operating on 15-digit numbers and 4th-order
- differences, with a printer.
-
- 1858. The difference engine of 1853 does its only useful calculation,
- producing a set of astronomical tables for an observatory in Albany,
- New York. The person who spent money on it is fired and the machine ends up
- in the Smithsonian Institute. (The Scheutzes did make a second similar machine,
- which had a long useful life in the British government.)
-
- 1871. Babbage produces a prototype section of the Analytical Engine's
- "mill" (CPU) and printer. No more is ever assembled.
-
- 1878. Ramon Verea, living in New York City, invents a calculator with an
- internal multiplication table; this is much faster than the shifting
- carriage or other digital methods. He isn't interested in putting it into
- production; he just wants to show that a Spaniard can invent as well as
- an American.
-
- 1879. A committee investigates the feasibility of completing the Analytical
- Engine and concludes that it is impossible now that Babbage is dead.
- The project becomes somewhat forgotten and is unknown to most of the people
- mentioned in the last part of this chronology.
-
- 1885. Dorr E. Felt (1862-1930), of Chicago, makes his "Comptometer".
- This is the first calculator where numbers are entered by pressing
- keys as opposed to being dialed in or similar awkward methods.
-
- 1889. Felt invents the first printing desk calculator.
-
- 1890. US Census results are tabulated for the first time with significant
- mechanical aid: the punch card tabulators of Herman Hollerith
- (1860-1929) of MIT, Cambridge, Mass. This is the start of the punch card
- industry (thus establishing the size of the card, the same as a US $1 bill
- (then)). The cost of the census tabulation rises by 98% from the previous
- one, in part because of the temptation to use the machines to the fullest
- and tabulate more data than formerly possible. The use of electricity to
- read the cards is also significant.
-
- 1892. William S. Burroughs (1857-1898), of St. Louis, invents a machine
- similar to Felt's but more robust, and this is the one that really
- starts the office calculator industry. (The calculators are still hand
- powered at this point, but electrified ones follow in not too many years.)
-
- 1937. George Stibitz (c.1910-) of Bell Labs, New York City, constructs a
- demonstration 1-bit binary adder using relays.
-
- 1937. Alan M. Turing (1912-1954), of Cambridge University, England, publishes
- a paper on "computable numbers", which solves a mathematical problem
- by considering as a mathematical device the theoretical simplified computer
- that came to be called a Turing machine.
-
- 1938. Claude E. Shannon (c.1918-) publishes a paper on the implementation of
- symbolic logic using relays.
-
- 1938. Konrad Zuse (1910-) of Berlin completes a prototype mechanical
- programmable calculator, later called the "Z1". Its memory used sliding
- metal parts and stored about 1000 bits. The arithmetic unit was unreliable.
-
- Oct 1939. Stibitz and Samuel Williams complete the "Model I", a calculator
- using relay logic. It is controlled through modified teletypes
- and these can be connected through phone lines. Later machines in the series
- also have some programmability.
-
- c.Oct 1939. John V. Atanasoff (1903-) and Clifford Berry, of Iowa State
- College, Ames, Iowa, complete a prototype 16-bit adder. This
- is the first machine to calculate using vacuum tubes.
-
- c.1940. Zuse completes the "Z2", keeping the mechanical memory but using
- relay logic. He can't interest anyone in funding him.
-
- Dec 1941. Zuse, having promised to a research institute a special-purpose
- calculator for their needs, actually builds them the "Z3", which
- is the first operational program-controlled calculator, and has 64 22-bit
- words of memory. However, its programmability doesn't include a conditional-
- jump instruction; Zuse never had that idea. The program is on punched tape.
- The machine includes 2600 relays, and a multiplication takes 3-5 seconds.
-
- Spring 1942. Atanasoff and Berry complete a special-purpose calculator for
- solving systems of simultaneous linear equations, later called
- the "ABC" ("Atanasoff-Berry Computer"). This has 60 50-bit words of memory
- in the form of capacitors (with refresh circuits) mounted on two revolving
- drums. The clock speed is 60 Hz, and an addition takes 1 second.
- For secondary memory it uses punch cards, with the holes being burned
- rather than punched in them, moved around by the user. (The punch card
- system's error rate was never reduced beyond 0.001%, which wasn't good enough.)
- Atanasoff then left Iowa State, and apparently lost all interest
- in digital computing machines.
- [You can read more about the ABC in an article in one of the issues
- of Scientific American from this summer, which called it the first computer.]
-
- Jan 1943. Howard H. Aiken (1900-1973) and his team at Harvard University,
- Cambridge, Mass. (with backing from IBM), complete the "ASCC
- Mark I" ("Automatic Sequence-Controlled Calculator Mark I"). This is the first
- program-controlled calculator to be widely known: Aiken was to Zuse as Pascal
- to Schickard. The machine is about 60 feet long and weighs 5 tons; it has
- 72 accumulators.
-
- Dec 1943. Alan Turing and his team at Bletchley Park, near Cambridge, England,
- complete the first version of the "Colossus". This is a secret,
- special-purpose decryption machine, not exactly a calculator but close kin.
- It includes 2400 tubes for logic and reads characters (optically) from 5
- long paper tape loops moving at 5000 characters per second.
-
- Nov 1945. John W. Mauchly (pronounced Mawkly; 1907-80) and J. Presper Eckert
- (1919-) and their team at the Moore School of the University of
- Pennsylvania, Philadelphia, complete the "ENIAC" ("Electronic Numerator,
- Integrator, Analyzer, and Computer") for the US Army's Ballistics Research
- Lab. (Too late for the war and 200% over budget -- problems that would face
- Eckert and Mauchly again on later projects.)
- The machine is a secret (until Feb 1946) program-controlled calculator.
- Its only memory is 20 10-digit accumulators (4 were originally planned).
- The accumulators and logic use vacuum tubes, 17648 of them altogether.
- The machine weighs 30 tons, covers about 1000 square feet of floor, and
- consumes what is either 174 kilowatts (233 horsepower) or 174 hp (130 kW).
- Its clock speed is 100 kHz; it can do 5000 additions per second, 333 multip-
- lications per second. It reads data from punch cards, and the program is
- set up on a plugboard (considered reasonable since the same or similar
- program would tend to be used for weeks at a time).
- Mauchly and Eckert apply for a patent. The university disputes
- this at first, but they settle. The patent is finally granted in 1964, but
- is overturned in 1973, in part because of the previous work by Atanasoff.
-
- 1945-46. John von Neumann (1903-1957) joins the ENIAC team and writes a
- report describing the future computer eventually built as the
- "EDVAC" ("Electronic Discrete Variable Automatic Computer" (!)). This
- report was the first description of the design of a stored-program computer.
- An early draft which fails to credit other team members such as Eckert
- and Mauchly gets too-wide distribution, leading to von Neumann getting
- too much credit, e.g., the term "von Neumann computer" which is derived from
- this paper.
-
- Jan 1948. Wallace Eckert (1902-1971, no relation to Presper Eckert and not
- mentioned again in this article) of IBM, with his team, completes
- the "SSEC" ("Selective Sequence Electronic Calculator"). This technological
- hybrid has vacuum tube logic with 8 20-digit registers, 150 20-digit words
- of relay memory, and a program that is partly stored but also controlled
- by a plugboard. IBM considers it the first computer.
-
- Jun 1948. Max Newman, F. C. Williams, and their team at Manchester Univers-
- ity, Manchester, England, complete a prototype machine called the
- "Mark I". This is the first machine that everyone would call a computer,
- because it's the first with a true stored-program capability.
- It uses a new type of memory invented by Williams, which uses the
- residual charges left on the screen of a CRT after the electron beam has been
- fired at it. (The bits are read by firing another beam through them and
- reading the voltage at an electrode beyond the screen.) This is a bit
- unreliable but is fast, relatively cheap, and much more compact (with room
- for about 1024 or 2048 bits per tube) than any other memory then existing.
- The Mark I uses six of them, but I don't know of how many bits.
- Its programs are initially entered in binary on a keyboard, and
- the output is read in binary from another CRT. Later Turing joins the
- team and devises a primitive form of assembly language, one of several
- developed in different places.
- Newman was the first person shown Turing's 1937 paper in draft form.
-
- 1949-51. Jay W. Forrester and his team at MIT construct the "Whirlwind" for
- the US Navy's Office of Research and Inventions. The vague date
- is because it advanced to full-time operational status gradually. Originally
- it had 3300 tubes and 8900 crystal diodes. It occupied 2500 square feet
- of floor. Its 2048 16-bit words of CRT memory used up tubes so fast they
- were costing $32000 per month.
- This was the first computer designed for real-time work, hence the
- short word size; it could do 500000 additions or 50000 multiplications
- per second.
-
- Spring 1949. Forrester conceives the idea of magnetic core memory. The first
- practical form, 4 years later, will replace the Whirlwind's
- CRT memory and render all then existing types obsolete.
-
- Jun 1949. Maurice Wilkes (1913-) and his team at Cambridge University
- complete the "EDSAC" ("Electronic Delay Storage Automatic Computer"),
- which is closely based on the EDVAC design report from von Neumann's group.
- This is the first operational stored-program computer that's not a prototype.
- Its I/O is by paper tape, and it has a sort of mechanical read-only memory
- for booting, consisting of rotary telephone switches.
- Its main memory is of another new type, invented by Eckert: the
- "ultrasonic" or "delay line" memory. In this type, the data is repeatedly
- converted back and forth between electrical pulses and ultrasonic pulses;
- only the bits currently in electrical form are accessible. (The ultrasonic
- pulses were typically fired from one end of a tank of mercury to the other,
- though other substances were also used.) In the EDSAC, 32 mercury tanks
- 5 feet long give a total of 256 35-bit words of memory.
-
- Aug 1949. Eckert and Mauchly, having formed their own company, complete
- the "BINAC" ("Binary Automatic Computer") for the US Air Force.
- Designed as a first step to in-flight computers, this has dual (redundant)
- processors each with 700 tubes and 512 31-bit words of memory. Each
- processor occupies only 4 square feet of floor space and can do 3500
- additions or 1000 multiplications per second.
- The designers are thinking mostly of their forthcoming "UNIVAC"
- ("Universal Automatic Computer") and don't spend much time making the BINAC
- as reliable as it should be, but the tandem processors compensate somewhat.
-
- Feb 1951. Ferranti Ltd., of Manchester, England, completes the first
- commercial computer, also called the "Mark I". 8 of them are sold.
-
- Mar 1951. Eckert and Mauchly, having sold their company to Remington Rand,
- complete the first UNIVAC, which is the first US commercial computer.
- It has 1000 12-digit words of ultrasonic memory and can do 8333 additions
- or 555 multiplications per second; it contains 5000 tubes and covers
- 200 square feet of floor.
-
- 1951. Grace Murray Hopper (1906-), of Remington Rand, invents the modern
- concept of the compiler.
-
- 1951-52. The EDVAC is finally completed. It has 4000 tubes, 10000 crystal
- diodes, and 1024 44-bit words of ultrasonic memory. Its clock speed
- is 1 mHz.
-
- 1952. The IBM "Defense Calculator", later renamed the "701", the first
- IBM computer unless you count the SSEC, enters production at
- Poughkeepsie, New York. (The first one is delivered in March 1953; 19 are
- sold altogether. The memory is electrostatic and has 4096 36-bit words;
- it does 2200 multiplications per second.)
-
- 1952. Grace Murray Hopper implements the first compiler, the "A-0".
- (As with "computer", this is a somewhat arbitrary designation.)
-
- ----------------------------------------------------
-
- A few things have happened since then, too, but this margin is too narrow...
-
- Mark Brader "Inventions reached their limit long ago,
- SoftQuad Inc., Toronto and I see no hope for further development."
- utzoo!sq!msb, msb@sq.com -- Julius Frontinus, 1st century A.D.
-
-