Method for deleting objects from library resident optical disks by accumulating pending delete requests

• US 5,325,523 A
• Filed: 04/10/1991
• Issued: 06/28/1994
• Est. Priority Date: 04/10/1991
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Zelazny, Kimberly M., Beglin, Thomas W.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): MARCUS, STEPHEN
• Application Number:
  US07/683,768
• Time in Patent Office: 1,175 Days
• Field of Search: 364/200, 395/700, 395/145, 395/600, 395/425, 395/650, 395/725
• US Class Current: 1/1
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/41 Flat as opposed to hierarchical combination, e.g. library of tapes or discs, CD changer, or groups of record carriers that together store one title
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: G11B 27/34 Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing

Abstract

The response time of an automated optical disk library is improved by writing object delete requests to a deleted objects table before actually physically deleting those objects. By collecting object delete requests in a list of pending deletes for each volume in the library the number of necessary mounts are reduced. The delete requests in a list of pending deletes for a given volume are physically deleted just prior to performing a write or defrag request for that volume. The list of pending deletes for that volume are then deleted from the deleted objects table. During idle periods a predetermined number of pending delete requests will be performed for the currently mounted volume. If there are no pending delete requests for the currently mounted volume then a predetermined number of pending delete requests will be performed on the opposite side of the currently mounted volume. When all pending delete requests for both the currently mounted volume and the opposite side thereof have been completed the library-resident volume having the greatest amount of space to be deleted will be mounted and a predetermined number of pending deletes will be performed on that volume. This process continues as long as there are pending deletes. If all of the objects on an optical disk have expired then the next time that disk is mounted it will be reformatted.

Claims

1. In an information processing system, a machine-executed method of deleting objects from a volume, said machine-executed method comprising the steps of:

receiving a delete request for deleting an object from a first volume;

writing the delete request to a deleted objects table such that the delete request is added to a list of pending deletes for the first volume;

logically deleting the space associated with the delete request;

receiving a write request for the first volume;

mounting the first volume on a drive if the first volume is not already mounted;

determining whether said volume has expired; and

if all of the objects on said volume have expired;

deleting a list of pending deletes for said volume;

checking the expired status of an optical disk containing said volume when said volume is mounted; and

deleting all of the objects on the disk by reformatting the disk if the expired status is set;

if all of the objects on the volume have not expired;

deleting all of the objects on the first volume that are listed in the list of pending deletes;

adding logically deleted space of the first volume to current free space of the first volume; and

performing the write request.

2. The method according to claim 1 wherein delete request is user initiated.

3. In an information processing system, a machine-executed method of deleting objects from a volume, said machine-executed method comprising the steps of:

receiving defragmentation request for a first volume;

mounting the first volume on a drive if the first volume is not already mounted;

determining whether said volume has expired; and

if all of the objects on said volume have expired;

setting a volume empty status for said volume;

deleting a list of pending deletes for said volume;

checking the expired status of an optical disk containing said volume when said volume is mounted; and

deleting all of the objects on the disk by reformatting the disk if the expired status is set;

if all of the objects on said volume have not expired;

deleting all of the objects listed in a list of pending deletes for the first volume;

adding logically deleted space to current free space of the first volume; and

defragmenting the first volume.

4. The method according to claim 3 further comprising the steps of:

deleting one or more objects from a currently mounted volume during library idle periods;

if there are no objects to be deleted from the currently mounted volume during library idle periods;

mounting an unmounted volume having the greatest amount of logically deleted space; and

deleting objects in groups of one or more objects from said unmounted volume until all pending deletes have been performed.

6. The computer process according to claim 3 wherein the delete request is user initiated.

7. The computer process according to claim 3 further comprising the steps of:

receiving a defrag request for a second volume;

mounting the second volume on a drive if the second volume is currently unmounted;

deleting all objects from the second volume that are listed in a list of pending deletes for the second volume;

adding logically deleted space to current free space of the second volume; and

defragmenting the second volume.

5. A computer process for deleting objects from volumes in an automated storage library wherein the objects to be deleted are logically but not physically deleted until a predetermined event occurs, said automated storage library having a plurality of storage media wherein each storage medium has at least one volume for storing the objects thereon, the computer process comprising the steps of:

receiving a delete request for deleting an object from a first volume;

writing the delete request to a deleted objects table such that the delete request is added to alist of pending deletes for the first volume storing the object to be deleted, the space of the object being added to logically deleted space of the first volume;

receiving a write request for the first volume;

mounting the first volume if the first volume is not already mounted;

determining whether all of the objects stored on a storage medium have expired; and

if all of the objects on the storage medium have expired;

setting an expired status of the storage medium;

deleting a list of pending deletes for the storage medium; and

reformatting the storage medium when the storage medium is mounted;

if all of the objects on the storage medium have not expired;

deleting all objects on the first volume that are listed in the list of pending deletes for the first volume;

adding the logically deleted space to current free space of the first volume; and

performing the write request.

8. The method according to claim 5 further comprising the steps of:

deleting one or more pending deletes for a mounted volume;

if there are no pending deletes for the currently mounted volume;

mounting the opposite side of the currently mounted volume if the opposite side has pending deletes; and

deleting a predetermined number of objects from the opposite side during an library idle period; and

if there are no pending deletes for the opposite side;

mounting an unmounted volume having the greatest amount of logically deleted space during another idle period; and

deleting a predetermined number of objects on the unmounted volume.