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IP.com Disclosure Number: IPCOM000074506D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Canaday, GF: AUTHOR [+2]

Abstract

The drawing shows the format of a list of storage words allocated to various users of a data processing system. The first two words in the list are used for accessing the list. The numbers 8 through 12 identify the users to which other word locations have been allocated and the 0's identify unallocated words. The list is useful, for example, for assigning storage space to different users.

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The drawing shows the format of a list of storage words allocated to various users of a data processing system. The first two words in the list are used for accessing the list. The numbers 8 through 12 identify the users to which other word locations have been allocated and the 0's identify unallocated words. The list is useful, for example, for assigning storage space to different users.

The search word has a bit for each allocatable word of the table and a 1 stored in a bit location identifies the next word position to be accessed. The allocation word has a 1 for words that have been allocated and a 0 for words that are available to be allocated.

To enter new data in the list, the search and allocation words are first ANDed and this logical product is searched for a 1 in any bit position. Since coincident 1's in the search and allocation words signify that the search operation has advanced to a previously allocated word location, a 0 result from this operation signifies that the next space is vacant and that the operation to enter new data can proceed. The relative address of the vacant position is calculated from the position of the 1 in the search index and the user is given the address of the allocated word location. A 1 is entered in the corresponding position of the allocation word and the 1 in the search word is advanced to the next position.

Words can be removed from the list in either a first in, first out or last in, first out order. F...