Browse Prior Art Database

An Efficient Algorithm for Managing Pinned Control Blocks

IP.com Disclosure Number: IPCOM000103138D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Chang, A: AUTHOR [+4]

Abstract

Disclosed is a technique for managing pinned control blocks in a paging system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 73% of the total text.

An Efficient Algorithm for Managing Pinned Control Blocks

      Disclosed is a technique for managing pinned control blocks in
a paging system.

      Selected control blocks in a paging system must be fixed in
primary memory or pinned. The number of these control blocks may vary
over time based on the current system activity. Finally, it is often
required that managing of control blocks must be very efficient.

      A section of virtual memory is allocated to contain a large
array of the desired type of control block. A service is provided to
indicate how many of these control blocks various parts of the
operating system need. This service maintains a count of the number
of pinned control blocks that the system must have available at any
instance in time.

      Two free list are maintained. One is a list of the free pinned
control blocks and the other is a list of the free unpinned control
blocks. The number of allocated pinned control blocks plus the number
on the list of free pinned control blocks is always greater than the
number of pinned control blocks required.

      Both free lists are carefully maintained to minimize the number
of pages containing a control block. A free control block is placed
at the front of the list of pinned control blocks if its index is
less than the number required by the system. Otherwise, the control
block is placed on the pinned list if the number of free pinned
control blocks is too low and on the unpinned free lis...