Browse Prior Art Database

Read Only Memory

IP.com Disclosure Number: IPCOM000096174D
Original Publication Date: 1963-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Matick, RE: AUTHOR

Abstract

The read-only memory consists of permalloy film elements 11 having a thickness of 4000 to 8000 angstroms and exhibiting a uniaxial magnetic anisotropy or easy direction ED. Elements 1 1 are sandwiched between strip transmission lines 12 and 13. These supply drive fields with a field vector pointing into the hard direction HD. The drive pulses are generated in a word-addressed driving unit 17. Sensing is by figure-eight shaped conductor loops 15a and 15b placed directly above each element 11, where the sense lines run substantially parallel to direction ED. Information is stored in the memory by small bias magnets 16. These are above each bit position where 0 has to be stored. Magnets 16 are supported by carrier 17 and are strong enough to saturate associated elements 11 in direction HD.

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Read Only Memory

The read-only memory consists of permalloy film elements 11 having a thickness of 4000 to 8000 angstroms and exhibiting a uniaxial magnetic anisotropy or easy direction ED. Elements 1 1 are sandwiched between strip transmission lines 12 and 13. These supply drive fields with a field vector pointing into the hard direction HD.

The drive pulses are generated in a word-addressed driving unit 17. Sensing is by figure-eight shaped conductor loops 15a and 15b placed directly above each element 11, where the sense lines run substantially parallel to direction ED. Information is stored in the memory by small bias magnets 16. These are above each bit position where 0 has to be stored. Magnets 16 are supported by carrier 17 and are strong enough to saturate associated elements 11 in direction HD.

Since magnets 16 are external to the actual film array and strip line arrangement, the stored information can be changed by providing interchangeable carriers 17 with magnets 16 arranged in different patterns.

The binary 1 is represented by a split-up film element. Such element is disassociated into multiple domains which align in parallel but opposite directions along direction ED. The multiple domain structure is caused by the self- demagnetizing force which builds up within the film element as the thickness increases.

During interrogation, when a readout pulse field is applied to the film elements of a selected word, elements with a stored 0 remain unaffected....