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From: blymn@awadi.com.au (Brett Lymn)
Newsgroups: comp.os.386bsd.development
Subject: Re: File Truncation Philosophy
Date: 3 Apr 93 21:46:31
Organization: /usr/blymn/.organization
Lines: 35
Message-ID: <BLYMN.93Apr3214631@siren.awadi.com.au>
References: <C4tJ6C.C17@ns1.nodak.edu> <1pfteb$ch5@umd5.umd.edu>
NNTP-Posting-Host: siren.awadi.com.au
In-reply-to: mark@roissy.umd.edu's message of 1 Apr 1993 23:21:47 GMT
>>>>> On 1 Apr 1993 23:21:47 GMT, mark@roissy.umd.edu (Mark Sienkiewicz) said:
Mark> NNTP-Posting-Host: roissy.umd.edu
Mark> In article <C4tJ6C.C17@ns1.nodak.edu> tinguely@plains.NoDak.edu
(Mark Tinguely) writes:
[stuff deleted]
Mark> Idea 4: Copy the program text into the swap area
Mark> 4a- always. This causes a performance penalty when you start a
Mark> program.
Mark> 4b- when executing from a filesystem not known to be "reliable".
Mark> NFS. CDFS is unlikely to be a problem. various other
Mark> ideas here (e.g. 1,4c) might make UFS reliable. It would
Mark> probably work best if you had the kernel be conservative
Mark> about any "new" filesystem types. e.g. you don't know if
Mark> marksfs does what you need or not.
Mark> 4c- when the program file is opened for writing. You would have
Mark> to block the open until the copy was complete.
#define SARCASM
#ifdef SARCASM
Hey yer, how about
4d- have a special bit called, ummmmm, sticky (yeh that sounds
good) that will tell the vm system that the executable is
likely to be used again real soon now so do not reuse the
swap space
#endif
The system of copying the text to swap was how the original un*x
systems worked. The real problem with it is that you have to have as
much swap as real memory (otherwise you cannot use the real memory
that is not covered by swap) AND that swap will be filled with program
text that may not be being used. IMHO the current VM system is much
better.