Massachusetts Institute of Technology. Digital Computer Laboratory

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MIT DIC 6889. Project Whirlwind Memo M-1389. Bi-weekly progress report of Digital Computer Laboratory research teams.

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MIT DIC 6889. Project Whirlwind Memo M-1405. Bi-weekly progress report of Digital Computer Laboratory research teams.

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MIT DIC 6889. Project Whirlwind Memo M-1419. Bi-weekly progress report of Digital Computer Laboratory research teams.

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MIT DIC 6889. Project Whirlwind Memo M-1367. Bi-weekly progress report of Digital Computer Laboratory research teams.

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MIT DIC 6889. Project Whirlwind Memo M-1382. Bi-weekly progress report of Digital Computer Laboratory research teams.

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MIT DIC 6345. Project Whirlwind Limited Memo L-29. Memorandum on the visitors to the Digital Computer Laboratory from September 1, 1950 to September 1, 1951.

Scope and Contents MIT DIC 6889. Project Whirlwind Controlled Distribution Memo 6D-95. A small, ring-shaped, ferromagnetic core with properly "rectangular" B-H characteristics may be operated so that its flux polarity reverses only when the correct combination of two or three magnetizing windings are coincidentally excited. Such cores may then be used as memory devices and assembled into a two- or three-dimensional memory system with storage-cell selection at the intersection of two or three space...

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MIT DIC 6889. Project Whirlwind Engineering Note E-540. Engineering report on a fast core-tube register including a circuit diagram and experimental results.

Scope and Contents MIT DIC 6889. Project Whirlwind Engineering Note E-559. The free energy of magnetization is expressed as a fourth degree polynomial in the magnetization with a linear term due to an external field and quadratic and quartic terms due to Fermi, exchange, magnetostatic, etc., energies as well as to entropy effects. Below the Curie temperature the free energy function has three real extrema, namely two minima and a maximum, if the absolute magnitude of the external field lies below a...

Scope and Contents MIT DIC 6889. Project Whirlwind Memo M-2110. A linear selection memory in which each word is driven independently from a multi-position switch might have the following advantages over a coincident current memory: 1. No outputs from non-selected cores. 2. No limitation to memory size by delta voltages. 3. Large unipolarity output voltage pulses. 4. Possibility of operation on saturation Φ-I loop. 5. Common z and sensing winding. 6. Simpler...

Scope and Contents MIT DIC 6889. Project Whirlwind Engineering Note E-475. A magnetic-core gate to replace diodes is a necessity if an all-core computer is to be made feasible. A device is described composed of two magnetic cores and a resistance which will operate as a gate between the cores of a stepping register, replacing the diodes conventionally used. The theory of operation is presented, indicating an upper limit to the operating frequency of about 50 kc at present. A possible method of increasing the...

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MIT DIC 6889. Project Whirlwind Memo M-2240. The toggle-switch test storage units in WWI and MTC use large numbers of crystal diodes and vacuum tubes. A much simpler unit might be possible using a modified magnetic matrix switch which will both select the words and isolate outputs. Only one core per word will be needed.

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Project Whirlwind Engineering Note E-503. This memorandum contains the abstract of Report R-211, a Master's Thesis, by Kenneth H. Olsen.

Scope and Contents Project Whirlwind Report R-211. The random-access memory is an important element of a high-speed digital computer. This memory must be capable of operating at high speeds with long-time reliability, and should be compact and of low cost. The coincident-current magnetic memory has been proposed as a possible device which has these qualifications. It was one of the original purposes of this theses research to prove experimentally the feasibility of a coincident-current memory of useful size....

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Project Whirlwind Limited Memo L-32. Memorandum from Jay W. Forrester outlining goals for Project Lincoln, the Cape Cod System, and Whirlwind II, for the period from July 1952 to June 1953.

Scope and Contents MIT DIC 6889. Project Whirlwind Engineering Note E-512. A method for screening the Production Lots of ferrite cores to be tested for MTC is required because of testing limitations and large variations found between Production Lots. It is proposed that a sample of 100 cores be taken from each lot and tested at the factory. The mean of the sample must be between the Screening Limits specified for the lot to be accepted, from the manufacturer, for complete testing. The Per Cent Yield of the...

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MIT DIC 6889. Project Whirlwind Engineering Note E-454. A non-destructive read system for magnetic cores is proposed which involves a quadrature field and which promises to be fast.

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Project Whirlwind Memo M-2170. A good deal of delta and air-flux noise cancellation can be attained during readout by using the dФ/dt produced during the fall time of the read gate to cancel that produced during the rise time.

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MIT DIC 6889. Project Whirlwind Engineering Note E-464. A quantitative index of hysteresis-loop squareness i s defined. It can be determined directly from the hysteresis loop or by pulse test.

Scope and Contents MIT DIC 6889. Project Whirlwind Memo M-1744. Considering exchange and Fermi energy of a system of electrons together with magnetostatic, magnetostrictive and anisotropy forces, the internal energy of a magnetized system can be expressed as a function of its magnetization. As indicated by Slater, the entropy of the system is also a function of magnetization, so that the free energy can be expressed approximately as an even fourth degree polynomial in the magnetization in the absence of an...

Scope and Contents Project Whirlwind Controlled Distribution Memo 6D-103. A mechanism is proposed to show how the Fermi surface interacts with the Brillouin zone boundaries. The direction and relative magnitude of the variation of the c/a ratio for hexagonal crystals from the ideal value for close packing are predicted as a function of the electron-atom ratio, and these predictions are compared with values of lattice parameters which are reported in the literature. Reprinted from The Physical Review, Vol. 89,...

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MIT DIC 6889. Project Whirlwind Memo M-1929. The undersigned continued the discussion on FeNi₃ initiated by Dudley Buck at the seminar on magnetism, the meaning of order-disorder and entropy were examined. Hysteresis loops, saturation magnetization and Curie point of ordered and disordered states were contrasted and their differences tentatively explained.

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Project Whirlwind Memo M-1859. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1890. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1826. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1921. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1976. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-2113. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1805. Bi-weekly progress report of Digital Computer Laboratory research teams.

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Project Whirlwind Memo M-1944. Bi-weekly progress report of Digital Computer Laboratory research teams.