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First In/First Out Queue With Program Controlled Directory Search

IP.com Disclosure Number: IPCOM000083418D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Benedict, M: AUTHOR

Abstract

In the system of the drawing, a next command is entered into a store 2 at a location identified by an in-pointer and a current command is read from the store at a location identified by an out-pointer. The pointers are advanced as read and write operations take place in the store 2. A compare operation is performed on the in-pointer and the out-pointer.

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First In/First Out Queue With Program Controlled Directory Search

In the system of the drawing, a next command is entered into a store 2 at a location identified by an in-pointer and a current command is read from the store at a location identified by an out-pointer. The pointers are advanced as read and write operations take place in the store 2. A compare operation is performed on the in-pointer and the out-pointer.

When the next command has been entered in the last available location in the store, the in-pointer is stepped into equality with the out-pointer, and a condition Queue Busy is signalled to the controlled program. When the last command has been read from the store, the out-pointer is stepped into equality with the in-pointer, and a signal Queue Empty is supplied to the controlled program. The in-pointer is stepped away from equality with the out-pointer when a next command has been entered into an empty queue.

A command has an address field that may be held with additional information in a second store 3. In response to the signal Start or in response to the completion of a previous search, this address is gated into a search register. The control program may also supply an address to the search register, and the control program sets a mask register that establishes which bits of the search register are to control the search operation.

The control program sets a starting address into an address register 4 for the store 3 and it sets a counter with a...