What is /dec/shm? Is is kind of a RAM drive? I have had an entry in my df listing and /etc/fstab for it for quite a while. I was just wondering what it was... Later Mike -- +----------------------------------------------------------------------+ | Digital Civilization magazine: http://www.digitalcivilization.ca | |Call-A.P.P.L.E. and the Digital Civilization http://www.callapple.org | | http://members.shaw.ca/pfaiffer = Mike Pfaiffer (B.A., B.Sc.) | +----------------------------------------------------------------------+ ----- BEGIN GEEK CODE BLOCK ----- Version: 3.12 GCS/G/IT/PA/SS d s+:- a? C++ UL L++ W++ N++ o+ K- w(---) O+@ M++@ V PS+ PE !PGP t+ 5+ X R tv b+ DI+++ D++ G e++* h! r-- !y-- UF++ ------ END GEEK CODE BLOCK ------
On Tue, 2004-07-20 at 23:02, Mike Pfaiffer wrote:
What is /dec/shm? Is is kind of a RAM drive? I have had an entry in my df
[sean@bob sean]$ mount ... none on /dev/shm type tmpfs (rw) [sean@bob sean]$ locate tmpfs /usr/src/linux-2.4.22-1.2188.nptl/include/config/tmpfs.h /usr/src/linux-2.4.22-1.2197.nptl/Documentation/filesystems/tmpfs.txt /usr/src/linux-2.4.22-1.2197.nptl/fs/intermezzo/journal_tmpfs.c [sean@bob sean]$ more /usr/src/linux-2.4.22-1.2197.nptl/Documentation/filesystems/tmpfs.txt Tmpfs is a file system which keeps all files in virtual memory. ... Who uses it? shm is an acronym for SHared Memory. From the shm_open(3) man page there is a note:
The POSIX shared memory object implementation on Linux 2.4 makes use of a dedicated file system, which is normally mounted under /dev/shm.
"UNIX Network Programming" by Stevens explains shm and other forms of IPC far better than I could ever hope to. Sean -- Sean A. Walberg <sean@ertw.com> http://www.ertw.com
On July 21, 2004 06:49 am, Sean A. Walberg wrote:
On Tue, 2004-07-20 at 23:02, Mike Pfaiffer wrote: <snip>
Thanks. I'm still not quite sure what's up. That's OK though. Now I have a vague idea what it is. I was kind of worried it was something about half the size of my physical memory. The important thing is it's supposed to be there. ;-) Later Mike -- +----------------------------------------------------------------------+ | Digital Civilization magazine: http://www.digitalcivilization.ca | |Call-A.P.P.L.E. and the Digital Civilization http://www.callapple.org | | http://members.shaw.ca/pfaiffer = Mike Pfaiffer (B.A., B.Sc.) | +----------------------------------------------------------------------+ ----- BEGIN GEEK CODE BLOCK ----- Version: 3.12 GCS/G/IT/PA/SS d s+:- a? C++ UL L++ W++ N++ o+ K- w(---) O+@ M++@ V PS+ PE !PGP t+ 5+ X R tv b+ DI+++ D++ G e++* h! r-- !y-- UF++ ------ END GEEK CODE BLOCK ------
participants (2)
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Mike Pfaiffer -
Sean A. Walberg