SUMMARY: Increasing the Number of file descriptors

From: Steve Pomush (
Date: Tue Jul 06 1993 - 02:34:32 CDT

Sorry it took so long to summarize, but we have been very busy. My
original question was:

> We need to increase the number of file descriptors available to a process.
> Right now, if we run "limit descriptor" inside a C-shell, the result
> is "descriptor 64" . How do we increase this value. We think there
> is a kernel variable that can be changed, we just don't remember
> what its called and where its resides.

Everyone who responded mentioned the limit command in the csh shell:

csh> limit descriptor 256

However, Shankar Ishwar of AT&T Bell Labs also mentioned two other changes that
would apply to all users on the system:

256 is the MAX by default; However, if you need to go beyond this,
you will have to tweak the file: types.h in the kernel area's sys sub direc.
</usr/sys/sys/types.h> ==> <#define FD_SETSIZE 256>
If you want to change the default value from 64 to something diff., you
will have to tweak the file: /usr/sys/sys/param.h ==> <#define NOFILE 64>

Thanks to all the others that responded (sorry if I missed anyone):
uunet!!mike (Michael Sullivan)

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