Browse Prior Art Database

Smart Daemon - Smart Garbage Collection

IP.com Disclosure Number: IPCOM000111748D
Original Publication Date: 1994-Mar-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Whalen, PCF: AUTHOR

Abstract

The environment on Rational* machines requires that garbage collection be run on a daily basis to prevent a depletion of disk space which can force a system into a suspended state. Since garbage collection can take between three and six hours, it makes sense to look at garbage collection for efficiency increases.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 64% of the total text.

Smart Daemon - Smart Garbage Collection

      The environment on Rational* machines requires that garbage
collection be run on a daily basis to prevent a depletion of disk
space which can force a system into a suspended state.  Since garbage
collection can take between three and six hours, it makes sense to
look at garbage collection for efficiency increases.

      The default collection routine is Disk Daemon.  Disk Daemon
will execute every day at a predefined time.  In addition, when free
space on a volume goes below the "Start Collection" threshold, that
volume is immediately put on the garbage-collection queue.

      There are several inefficiencies with this system.  If a volume
is running garbage collection for any reason when the Disk Daemon
starts running, that volume will still be put on the
garbage-collection queue.  Further, if the Disk Daemon has started a
volume, and while collecting, that same volume crosses threshold, it
will be put back on the queue.  Thus, in these cases, a single volume
will run twice.

      The order that the Disk Daemon will run the volumes is also
inefficient: the queue is not a priority queue so that volumes with
considerable free space may be run before volumes with hardly any
free space.

      The Smart Daemon program avoids these inefficiencies.  First,
any volumes which have finished collection recently (within six
hours) will be noted and not run again.  However, if time permits and
a volume that r...