Browse Prior Art Database

Reducing the Incidence of System Hang in a Multiprogramming Computer System

IP.com Disclosure Number: IPCOM000123772D
Original Publication Date: 1999-Apr-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 24K

Publishing Venue

IBM

Related People

Balzi, F: AUTHOR [+2]

Abstract

Today, multiprogramming systems do not usually maintain all the data in physical memory but swap the data to the hard disk using virtual memory, which maintains in physical memory only the portion of the program that is really necessary to the program, all the rest being swapped out to the hard disk. Clearly, if there is no more room on the hard disk, the operating system cannot swap pages of virtual memory, leading to a hang of the system.

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Reducing the Incidence of System Hang in a Multiprogramming Computer
System

   Today, multiprogramming systems do not usually maintain
all the data in physical memory but swap the data to the hard disk
using virtual memory, which maintains in physical memory only the
portion of the program that is really necessary to the program, all
the rest being swapped out to the hard disk.  Clearly, if there is no
more room on the hard disk, the operating system cannot swap pages of
virtual memory, leading to a hang of the system.

   To mitigate against such hangs, the system creates a set of
reserve files.  When there is no free space on a selected drive, a
reserve file is deleted and the system administrator alerted to the
level of criticality reached on the system.  When the necessary
space is again available, the reserve file is re-created.  If we
want to avoid a deadlock for the memory, instead of reserve files
one would use reserve memory blocks, and in general blocks of the
resourced used.