Date: Wed, 1 Mar 2000 14:57:38 -0500 From: Christopher Masto <chris@netmonger.net> To: John Polstra <jdp@polstra.com> Cc: current@freebsd.org Subject: Re: Shared memory - Was: 2 Queries Message-ID: <20000301145737.A22521@netmonger.net> In-Reply-To: <200003011928.LAA75785@vashon.polstra.com>; from John Polstra on Wed, Mar 01, 2000 at 11:28:13AM -0800 References: <20000229021327.E21720@fw.wintelcom.net> <20000229134143.B4903@netmonger.net> <20000301182028.C61034@plab.ku.dk> <20000301124613.A15018@netmonger.net> <200003011928.LAA75785@vashon.polstra.com>
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On Wed, Mar 01, 2000 at 11:28:13AM -0800, John Polstra wrote: > > It takes no more than a well-designed operating system service to > > ensure that badly written programs don't fail to release resources > > when they crash. > > We didn't design that particular service. That's why it's called > System V shared memory. I did mean to imply that it was poorly designed, but not that it was designed by FreeBSD's designers. > Also, it's persistent for legitimate design reasons, just like files > are. Applications need to clean up after themselves. You can have many more than 32 files. Files are (usually) well-organized and have names, so you can wipe out your web browser's cache or lock file relatively easily. Files take up a negligible fraction of the available file space. SysV shared memory is limited, unnamed, unorganized, and uses up a very scarce resource. > The OS has no way of knowing whether an application wants its shared > memory segments to survive after it terminates. That's unfortunate. That's one of the reasons I try to stay away from SysV IPC. I don't like to have to reboot. -- Christopher Masto Senior Network Monkey NetMonger Communications chris@netmonger.net info@netmonger.net http://www.netmonger.net Free yourself, free your machine, free the daemon -- http://www.freebsd.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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