2.9BSD/usr/man/man2/mount.2

.TH MOUNT 2 
.UC
.SH NAME
mount, umount \- mount or remove file system
.SH SYNOPSIS
.B mount(special, name, rwflag)
.br
.B char *special, *name;
.PP
.B umount(special)
.br
.B char *special;
.SH DESCRIPTION
.I Mount
announces to the system that a removable file system has
been mounted on
the block-structured special file
.I special;
from now on, references to file
.I name
will refer to
the root file on the newly mounted file system.
.I Special
and
.I name
are pointers to null-terminated strings
containing the appropriate path names.
.PP
.I Name
must exist already. 
.I Name
must be a directory (unless the root of the mounted file system
is not a directory).
Its old contents
are inaccessible while the file system
is mounted.
.PP
The
.I rwflag
argument determines whether
the file system can be written on; if it is 0 writing
is allowed, if non-zero no writing is done.
Physically write-protected and magnetic
tape file systems must be mounted read-only or
errors will occur when access times are updated,
whether or not any
explicit write is attempted.
.PP
.I Umount
announces to the system that the
.I special
file is no longer to contain a removable file system.
The associated file reverts to its ordinary interpretation.
.SH ERRORS
.I Mount
will fail if:
.TP 20
[EPERM]
The process's effective user ID is not the super-user.
.TP 20
[ENODEV]
.I Special
does not exist.
.TP 20
[ENOTBLK]
.I Special
is not a block device.
.TP 20
[ENXIO]
The major device number of
.I special
is out of range (this indicates no device driver exists for the associated
hardware).
.TP 20
[EINVAL]
The path name
.I name
contains a non-ASCII byte.
.TP 20
[ENOTDIR]
A component of the path prefix in
.I name
is not a directory.
.TP 20
[EROFS]
.I Name
resides on a read-only file system.
.TP 20
[EBUSY]
.I Name
is not a directory or another process currently holds a reference to it.
.TP 20
[EBUSY]
No space remains in the mount table.
.PP
.I Umount
may fail with one of the following errors:
.TP 20
[EPERM]
The process's effective user ID is not the super-user.
.TP 20
[ENODEV]
.I Special
does not exist.
.TP 20
[ENOTBLK]
.I Special
is not a block device.
.TP 20
[ENXIO]
The major device number of
.I special
is out of range (this indicates no device driver exists for the associated
hardware).
.TP 20
[EINVAL]
The requested device is not in the mount table.
.TP 20
[EBUSY]
A process is holding a reference to a file located on the file system.
.SH "SEE ALSO"
mount(8)
.SH ASSEMBLER
(mount = 21.)
.br
.B sys  mount; special; name; rwflag
.PP
(umount = 22.)
.br
.B sys  umount; special