Detail View

Object Name: IBM ASCC-Mark I cams, counters, and relays
Date: 1939-1944
Inventory Number: 1997-1-0234
Classification: Computer Part
User: Harvard Computation Laboratory
founded 1944
Maker: Howard H. Aiken
1900 - 1973
Maker: Benjamin M. Durfee
1897 - 1980
Maker: Frank E. Hamilton
1898 - 1972
Maker: Clair D. Lake
1888 - 1958
Maker: Robert V. D. Campbell
born 1916
User: Grace Murray Hopper
1906 - 1992
User: Richard M. Bloch
1922 - 2000
User: United States Navy
founded 1775
Cultural Region: United States
City of Origin: Endicott
City of Use: Cambridge
Dimensions: 19.3 x 25 x 18.5 cm (7 5/8 x 9 13/16 x 7 5/16 in.)
Materials: rubber, copper
Description: Heavy piece of apparatus, which would be roughly cubic except for the sloping front. Metal casing on the sides and back, with several interlocking gears on the right side. On the front, near the bottom, is a row of nine white rotating discs, each attached to a toothed wheel. The numbers "1" and "9" are printed on the top and bottom, respectively, on the portion of each disc that is visible. [Presumably the numbers in between are printed on the portion of the discs not in view.] Above the white discs is a row of seventeen thin pieces of silver metal.

Above the thin metal pieces are nine large, black, toothed wheels, each with a curved piece of orange metal to the right of it. Several thin, evenly spaced, bronze colored metal bars run horizontally across the nine orange pieces of metal, with a black bolt fastening them to each. Thin, curved metal rods run along the left of each orange piece of metal, and are bolted to the bottom.

Above the orange bars is a horizontal brown metal bar, with ten bronze colored bolts on the front of it. At the very top of the apparatus is a row of eight brown, rectangular pieces of metal, each bolted to a silver piece of metal that extends behind the instrument, and another piece of brown metal.

At the bottom right of the instrument is a small, silver metal ledge with a black cylinder standing on it connected to a black wire. Beside the black cylinder is a front fracing metal rectangle with two bronze pieces of metal, potentially binding posts, attached to it.
Signed: unsigned
Inscribed: on back: 3-44

on back, towards bottom, on side with gears: S
Function: Part of the IBM Automatic Sequence Controlled Calculator, commonly known as the Harvard MARK I.

According to a brochure published by IBM in 1945:
"The IBM Automatic Sequence Controlled Calculator, an algebraic mechanism employing a unique automatic sequence control, is designed to solve, rapidly and accurately, practically any known problem in applied mathematics."

A detailed description of the history of MARK I, as well as how it works, can be found on the following website.
Curatorial Remarks: accompanying card reads: "The improved I.B.M. Cams, Counters, and Relays used in The Automatic Sequence Controlled Calculator were designed by Mr. Clair D. Lake, assisted by Mr. Wesley Pfaff."
Primary Sources: See IBM archives website for a history of MARK I.


Provenance: On March 13, 1997, the instrument was picked up from the Howard H. Aiken Computation Laboratory, 33 Oxford Street. It was transferred to the Collection by Edward P. Jackson, Facilities Manager in the Division of Engineering and Applied Sciences. Aiken Laboratory was to be destroyed during the summer of 1997 to make way for the new computing building. The instrument would have been disposed of if CHSI had not taken it. Was formerly on exhibition in the entrance area adjacent to the IBM Mark I Computer on the first floor of the Science Centre, Harvard University.
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