11/3/71 DIRECTORY (V)
NAME format of directories
SYNOPSIS --
DESCRIPTION A directory behaves exactly like an ordinary
file, save that no user may write into a direc-
tory. The fact that a file is a directory is in-
dicated by a bit in the flag word of its i-node
entry.
Directory entries are 10 bytes long. The first
word is the i-node of the file represented by the
entry, if non-zero; if zero, the entry is empty.
Bytes 2-9 represent the (8-character) file name,
null padded on the right. These bytes are not
necessarily cleared for empty slots.
By convention, the first two entries in each di-
rectory are for "." and "..". The first is an
entry for the directory itself. The second is
for the parent directory. The meaning of ".." is
modified for the root directory of the master
file system and for the root directories of re-
movable file systems. In the first case, there
is no parent, and in the second, the system does
not permit off-device references without a mount
system call. Therefore in both cases ".." has
the same meaning as ".".
FILES --
SEE ALSO file system format
DIAGNOSTICS --
BUGS --
OWNER ken, dmr