Browse Prior Art Database

Shared Directory

IP.com Disclosure Number: IPCOM000075232D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Enger, TA: AUTHOR

Abstract

The drawing shows a Directory 1, or index array, which is used for various data processing system operations. In particular, it may be desired to insert Data in the Directory which is to be associated with address information specified by address bits 0 - 23 generated in the data processing system. In normal operation, certain subsets of storage addresses are logically formed into 128 groups of addresses and correspond to 128 addressable locations in the Directory. These groups are specified by address bits 14 - 20. Any of the addresses within a particular group specified will have the associated Data inserted in a predetermined location of the Directory, as specified by bits 14 - 20. Associated with any particular address specified, is to be data or control information.

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Shared Directory

The drawing shows a Directory 1, or index array, which is used for various data processing system operations. In particular, it may be desired to insert Data in the Directory which is to be associated with address information specified by address bits 0 - 23 generated in the data processing system. In normal operation, certain subsets of storage addresses are logically formed into 128 groups of addresses and correspond to 128 addressable locations in the Directory. These groups are specified by address bits 14 - 20. Any of the addresses within a particular group specified will have the associated Data inserted in a predetermined location of the Directory, as specified by bits 14 - 20. Associated with any particular address specified, is to be data or control information. Each time a new address is provided from a user, a determination is made as to whether or not the data associated with that address is resident in the Directory 1. To make this determination, the address bits 14 - 20 are utilized in an Address Decoder 2 to access the location specified by bits 14 - 20. The Index portion (remaining address bits) of the location specified is read from the Directory and compared with the remaining bits of the address from the user, to determine if the particular address of the subset is the one being specified and has data within the directory. The comparison is made in a compare circuit 3, which, if a compare is made, will gate the associated data or control information from a gate 4 to the user.

In using a Directory approach as described above, difficulty is encountered when a number of users of the system are permitted to utilize identical addresses but require different data or control informati...