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From: mwang@watmath.UUCP (mwang)
Newsgroups: ont.events
Subject: UW Essay Pres., Mr. Wright on "Backward Error Recovery in a UNIX Environment".
Message-ID: <196@watmath.UUCP>
Date: Thu, 21-Nov-85 12:12:11 EST
Article-I.D.: watmath.196
Posted: Thu Nov 21 12:12:11 1985
Date-Received: Sat, 23-Nov-85 00:14:07 EST
Expires: Tue, 26-Nov-85 00:00:00 EST
Organization: U of Waterloo, Ontario
Lines: 41


DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES

ESSAY PRESENTATION

                    - Monday, November 25, 1985.

Mr.  Michael Wright, a graduate student of this depart-
ment, will speak on ``Backward Error Recovery in a UNIX
Environment''.

TIME:                3:30 PM

ROOM:              MC 6091A

ABSTRACT

Backward  error  recovery is an important technique for
recovery in software systems that are designed to func-
tion  as  specified, even in the presence of unforeseen
errors  caused  by  design  faults  or  faults  in  the
environment.   The  presentation will begin with a gen-
eral  discussion  of  backward  error  recovery and its
variants,  including  both  inclusive and disjoint mul-
tilevel recovery.

The  provision  of  backward  error  recovery  has been
incorporated  into IOSYS, an entension of the UNIX sys-
tem  interface  that  provides a simple file and record
management  system for experimentation with data struc-
tures.   The  recovery facility is quite flexible, sup-
porting  both  inclusive and disjoint recovery.  A pro-
gram   using  disjoint  recovery  can  supply  its  own
recovery  routines.  Since a program also has full con-
trol  over recovery regions (which need not be nested),
this  provides  a most general tool for experimentation
with  backward  error  recovery.   A description of the
facility, with some implementation details and measure-
ments of its efficiency, will be given.