Date: Sun, 12 Aug 2001 03:21:53 -0400 From: Jules Gilbert <jules@aasp.net> To: freebsd-questions@FreeBSD.ORG Subject: simple, stupid question... Message-ID: <3B762E90.E9DCF329@aasp.net>
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This is a multi-part message in MIME format. --------------5E8084FD84849473F97B6709 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I am not a BSD whiz. But I have a bunch of BSD systems which run all the time, and occasionally one of them comes up with a bright idea 'he' wants to write to a common file on one of the machines. That way I can see it in the morning. Now, the thing is, it could happen that two machines attempt to do an 'fopen' concurrently, with the second argument being "ab", ie., append binary. All machines talk to a common directory (which exists on a single machine) over an NFS based architecture. These machines spend most of their time thinking. I was considering allowing each machine a small slot of time, so that a deadlock on the common resource would be impossible. (First machine gets the first 10 seconds of a minute. Second machine gets the second 10 seconds of a minute, etc...) These machines spend most of their life thinking deep thoughts and only occasionally want to write to this single file on one directory on one of the machines, so the chance for collisions is small anyway... Another way is to cause one machine to successfully open the file, write out the brilliance, and the other machine to be told to try back in 30 seconds or a minute. Is a file lock (flock.tar), the right choice here? Years ago, I used a machine which had two macros, "ENQUE" and "DEQUE", which by naming the resource, assured me of serial access. (The thing is, it didn't always work. This was the Xerox Sigma 9; over 10,000 years ago...) Also, any advantage to using text files here instead of binary files, with respect to this problem? Please copy your answer to: jules@aasp.net and also me as: jg@medg.lcs.mit.edu By the way, THANK YOU BSD COMMUNITY -- this is a wonderful system, and while I am still learning how to best make use of it, I, along with thousands of others living on this planet, thank you for your efforts. This ingredient, among others, enables me to make a living without having to use/touch/feel/see/think about MS and that whole ugly mess... --------------5E8084FD84849473F97B6709 Content-Type: text/x-vcard; charset=us-ascii; name="jules.vcf" Content-Transfer-Encoding: 7bit Content-Description: Card for Jules Gilbert Content-Disposition: attachment; filename="jules.vcf" begin:vcard n:Gilbert;Jules x-mozilla-html:FALSE adr:;;PO Box 3351;North Attleborough;MA;02761; version:2.1 end:vcard --------------5E8084FD84849473F97B6709-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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