Browse Prior Art Database

Retaining and Reactivating Deleted Data Files

IP.com Disclosure Number: IPCOM000075997D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Bendel, MP: AUTHOR [+2]

Abstract

This is a method for retaining deleted data files so as to enable reactivation of the files if space occupied by them is not required by new active files. It is desirable to retain deleted files as long as possible because a need for them may arise due to the occurrence of an unforeseen event, such as accidental loss of hard copy files. Retention of deleted files is accomplished by changing their classification from a permanent to a nonpermanent status. All system information related to the deleted file is retained. Nonpermanent files cannot be accessed, and therefore, they do not interfere with other file operations.

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Retaining and Reactivating Deleted Data Files

This is a method for retaining deleted data files so as to enable reactivation of the files if space occupied by them is not required by new active files. It is desirable to retain deleted files as long as possible because a need for them may arise due to the occurrence of an unforeseen event, such as accidental loss of hard copy files. Retention of deleted files is accomplished by changing their classification from a permanent to a nonpermanent status. All system information related to the deleted file is retained. Nonpermanent files cannot be accessed, and therefore, they do not interfere with other file operations.

Fig. 1 illustrates the condition where file EE is in the deleted status. The index for file EE is X, rather than EE to make file EE inaccessible. The first and last tag is the same, i.e. 5, because EE is the only deleted file..

In Fig. 2, file CC is changed to a deleted file, file DD is added as a new permanent file and the deleted files are chained by making the first tag a 3 and the last tag a 5 in the index, and placing a forward pointer 5 for file CC and a backward pointer 3 for file EE. The index for file CC is changed to X to make it inaccessible.

Fig. 3 illustrates the reactivation of deleted file EE to a permanent file and adding a new file FF. The new active file FF is written over the file CC, because their is no space for it to be written elsewhere and file CC was still in the deleted status....