V3/usr/man/man2/mount.2

Find at most related files.
including files from this version of Unix. 
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NAME		mount  --  mount file system
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SYNOPSIS	sys  mount; special; name  / mount = 21.
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DESCRIPTION	mount_____
announces to the system that a removable file system has
been mounted on special file special_______;
from now on, references to file name____ will refer to
the root file on the newly mounted file system.
Special_______ and name____ are pointers to null-terminated strings
containing the appropriate path names.

Name____ must exist already.  If it had contents,
they are inaccessible while the file system
is mounted.
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SEE ALSO	mount(I), umount(II)
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DIAGNOSTICS	Error bit
(c-bit) set if: special_______ is inaccessible; name____
does not exist;
special_______ is already mounted;
name____ is not on the RF;
there are already four special files mounted.
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BUGS		At most
four removable devices can be mounted at a time.
This call should be restricted to the super-used.