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Immediate Access For Full Field Drum Transfer

IP.com Disclosure Number: IPCOM000098780D
Original Publication Date: 1959-Dec-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Byrne, WJ: AUTHOR [+3]

Abstract

A system is described for immediate transfer of information between a random access memory and a full field of a magnetic drum memory. The initial location in the random access memory 2 is added in address counter 3 to the location of the drum register under the reading or writing heads of the drum 1. The number of words of information to be transferred is placed in a word counter 4 from which one is subtracted for each word transferred. The address counter 3 selects the proper location from which or into which information is to be transferred. Transfer continues until the word counter 4 reaches zero.

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Immediate Access For Full Field Drum Transfer

A system is described for immediate transfer of information between a random access memory and a full field of a magnetic drum memory. The initial location in the random access memory 2 is added in address counter 3 to the location of the drum register under the reading or writing heads of the drum
1. The number of words of information to be transferred is placed in a word counter 4 from which one is subtracted for each word transferred. The address counter 3 selects the proper location from which or into which information is to be transferred. Transfer continues until the word counter 4 reaches zero. Immediate access reading of the drum is accomplished as follows:
(1) A block of space in core memory 2 is specified by designating the initial location X(1) and the number of words of information to be transferred N (where N is equal to the number of drum registers available in one drum field). X(1) is loaded into the input output address counter 3, and N is loaded into the input output word counter 4.
(2) The field from which the information is to be

read is specified.
(3) The contents of the first available drum register Y are read into the drum read write register 5 and thence to buffer 7. Simultaneously the value of the angular position counter 6 which ' contains Y is added to X(1) and the sum is stored in the input output address counter 3.
(4) Access to the core memory 2 is requested. When access is obtained, the contents of the input output address counter 3 are transferred to the memory address register 8 and the contents of the buffer 7 are transferred to the memory buffer register 9. When the memory write cycle starts, the memory address register 8 selects core memory register (X(1) + Y(N)) and the contents of drum register Y now in memory buffer register 9 are transferred into core memory location (X(1) + Y(N)).
(5) Steps 3, 4 and 5 are repeated for each succeeding drum location until N words have been transferred.

Writing on the drum is accomplished as follows:
(1) A block...