more on locks

Bradley K. Sherman bks at s27w007.pswfs.gov
Sat Sep 25 11:57:08 EST 1993


In article <HCOBB.93Sep24121839 at fly2.berkeley.edu> hcobb at fly2.berkeley.edu (Henry J. Cobb) writes:
> ...
>	I'll check for spec == "atomic" and do an open() with O_WRONLY |
>O_CREAT | O_EXCL followed by an fdopen() for lockfile itself.
> ...
>	All of the OS'es I am aware of have some procedure for atomic file
>creation, and I know of no other IPC which is common to all of them.  If
>this is a problem under say VMS or MVS or Novell or Appleshare, etc.,
>please let me know.
> ...

There was a nasty problem with NFS and SunOS 3.x where calls such
as this (open (...O_CREAT...)) appeared to succeed but which did
not preempt similar calls from other workstations.  This was
caused by local file caching. I do not know if this feature of
Sun/NFS interaction has been fixed in subsequent releases, or
whether it plagues other NFS implementations.

    --bks
-- 
Bradley K. Sherman               P.O. Box 245                    
Computer Scientist               Berkeley, CA, 94701
Dendrome Project                 510-559-6437 FAX: 510-559-6440  
Institute of Forest Genetics     Internet: bks at s27w007.pswfs.gov




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