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000141_icon-group-sender _Tue Jun 18 16:48:11 1996.msg
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1996-09-05
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Received: by cheltenham.cs.arizona.edu; Tue, 18 Jun 1996 16:20:23 MST
Date: Tue, 18 Jun 96 16:48:11 CDT
From: yak@comm.mot.com (Yarko Tymciurak)
Message-Id: <9606182148.AA03199@platov8>
To: H.Lawson@tees.ac.uk, icon-group@cs.arizona.edu
Subject: Re: Locking files
Errors-To: icon-group-errors@cs.arizona.edu
Status: O
| Date: Tue, 18 Jun 1996 13:11:43 +0100
| From: Hamish Lawson <H.Lawson@tees.ac.uk>
| To: icon-group@cs.arizona.edu
| Subject: Re: Locking files
|
| Jerzy Karczmarczuk wrote:
|
| > there is a cheap way of locking something
| > globally used for ages: the *creation* of a special "lock" file
| > just before entering the critical section (if it is absent,
| > otherwise sleep/wait), and the destruction after.
|
| Is there not a small risk that in the time between some process finding
| that the lock file doesn't exist and creating this file, another process
| might also find that the lock file doesn't exist, thereby breaking the
| exclusivity mechanism.
The lock "file" without this problem on UNIX is a directory -
its creation is guarenteed to be autonomous.
|
| | Hamish Lawson, School of Computing and Mathematics,
| | University of Teesside, Middlesbrough, Cleveland, UK, TS1 3BA
| | Tel: +44 1642 212695 Fax: +44 1642 342604
| | E-mail: H.Lawson@tees.ac.uk
|
Yarko Tymciurak
Motorola
iDEN Group