ruehl@ethz.UUCP (Roland Ruehl) (07/11/90)
Does anybody know if a running program on the Symmetry may crash
because (while it is running) the binary is removed from the disk ? Can
I prevent a program crash by restoring the binary at the place where it
was started and afterwards removed ?
Roland Ruehl uucp: uunet!mcsun!ethz!ruehl
Tel: (01) 256 5146 (Switzerland) eunet: ruehl@iis.ethz.ch
+411 256 5146 (International)
Integrated Systems Laboratory
ETH-Zentrum
8092 Zurichianj@sequent.UUCP (Ian Johnstone) (07/12/90)
In article <5063@ethz.UUCP> ruehl@ethz.UUCP (Roland Ruehl) writes: > >Does anybody know if a running program on the Symmetry may crash >because (while it is running) the binary is removed from the disk ? Can >I prevent a program crash by restoring the binary at the place where it >was started and afterwards removed ? > Removing the file doesn't release space until the last reference to the file is removed. Mapping a file (eg, by executing it as a binary) holds a reference to the file. Therefore no 'crash' can occur. -- Ian Johnstone uunet!sequent!ianj Sequent Computer Systems 503-626-5700 Beaverton, Oregon
amos@taux01.nsc.com (Amos Shapir) (07/12/90)
In article <5063@ethz.UUCP> ruehl@ethz.UUCP (Roland Ruehl) writes: > >Does anybody know if a running program on the Symmetry may crash >because (while it is running) the binary is removed from the disk ? Can >I prevent a program crash by restoring the binary at the place where it >was started and afterwards removed ? As in any UNIX system, a file is not actually destroyed, only its name in the directory is removed. As long as the file has a hard link in another directory, or is still open (for reading, writing or execution) it (its inode, actually) stays on the disk. A file is only destroyed when the last process which uses it does a "close" or exits. Restoring the binary does not do anything in that regard, since it creates a *different* file with the same name and contents. On the other hand, some systems have a bug which cause them to crash when a large number of files are removed and created at a short time. Symmetry might have inherited this bug. -- Amos Shapir amos@taux01.nsc.com, amos@nsc.nsc.com National Semiconductor (Israel) P.O.B. 3007, Herzlia 46104, Israel Tel. +972 52 522408 TWX: 33691, fax: +972-52-558322 GEO: 34 48 E / 32 10 N