Added dir.5 and filesys.5 manuals.
This commit is contained in:
@@ -0,0 +1,34 @@
|
||||
11/3/70 DIRECTORY (V)
|
||||
|
||||
|
||||
NAME format of directories
|
||||
|
||||
SYNOPSIS
|
||||
|
||||
DESCRIPTION A directory behaves exactly like an ordinary file, save
|
||||
that no user may write into a directory. The fact that a
|
||||
file is a directory is indicated by a bit in the flag word
|
||||
of its i-node entry.
|
||||
|
||||
Directory entries are 8 words long. The first word is the
|
||||
i-node of the file represented by the entry, if non-zero;
|
||||
if zero, the entry is empty.
|
||||
|
||||
Words 1-4 represent the (8-character) file name, space
|
||||
padded on the right. These words are not necessarily
|
||||
cleared for empty slots.
|
||||
|
||||
By convention, the first entry in each directory is
|
||||
for "dd", which is the "directory directory" that holds
|
||||
all the users' home directories and the "system" directory.
|
||||
The "system" directory contains "init" and "sh".
|
||||
|
||||
FILES
|
||||
|
||||
SEE ALSO file system format
|
||||
|
||||
DIAGNOSTICS
|
||||
|
||||
BUGS
|
||||
|
||||
OWNER ken, dmr
|
||||
+104
@@ -0,0 +1,104 @@
|
||||
11/3/70 FILE SYSTEM (V)
|
||||
|
||||
|
||||
NAME format of file system
|
||||
|
||||
SYNOPSIS
|
||||
|
||||
DESCRIPTION The RB09 fixed head disk has 8,000 64-word blocks on
|
||||
each of its two surfaces. Unix uses the second surface
|
||||
(physical blocks 8,000 to 15,999) and numbers them
|
||||
from logical block 0 to logical block 7,999. The following
|
||||
discussion refers to logical blocks.
|
||||
|
||||
The Unix filesystem is divided into 8,000 blocks of 64 words
|
||||
per block. Block 0 is the "sysdata" block. The first word
|
||||
points to the first block of the free-storage map. Each block
|
||||
in the free-storage map is structured as follows: the first
|
||||
word is the block number of the next block in the free-storage
|
||||
map, or zero if this is the end of the free-storage map. The
|
||||
next nine words hold free block numbers, or zero (no block number).
|
||||
|
||||
Block 1 on the filesystem is unused. (?)
|
||||
|
||||
I-numbers begin at 1, and the storage for i-nodes begins at
|
||||
block 2. Blocks 2 to 711 contain the i-nodes, with five
|
||||
consecutive i-nodes per block. Certain i-nodes are reserved for
|
||||
special files, directories and devices:
|
||||
|
||||
1 The core file written by "sys save" or a bad system call
|
||||
2 The "dd" directory directory
|
||||
3 The "system" directory
|
||||
6 The "ttyin" special file
|
||||
7 The "keyboard" (graphic-2) special file
|
||||
8 The "pptin" (paper tape reader) special file
|
||||
10 The "ttyout" special file
|
||||
11 The "display" (graphic-2) special file
|
||||
12 The "pptout" (paper tape punch) special file
|
||||
|
||||
|
||||
There is only one file system which is always mounted;
|
||||
it resides on the RB disk. This device is also used for
|
||||
swapping. The swap areas are at the high blocks on this device:
|
||||
blocks 6,400 to 7,999. These blocks do not appear in the free list.
|
||||
|
||||
Each i-node represents one file. The format of
|
||||
an i-node is as follows, where the left column represents
|
||||
the offset in words from the beginning of the i-node:
|
||||
|
||||
0 flags (see below)
|
||||
1 first indirect block or contents block
|
||||
...
|
||||
7 seventh indirect block or contents block
|
||||
8 user ID of owner
|
||||
9 link count
|
||||
10 size in words
|
||||
11 unique value assigned at creation
|
||||
|
||||
The flags are as follows:
|
||||
|
||||
400000 i-node is allocated
|
||||
200000 large file
|
||||
?????? allocated bit (always on)
|
||||
000040 special file
|
||||
000020 directory
|
||||
000010 read, owner
|
||||
000004 write, owner
|
||||
000002 read, non-owner
|
||||
000001 write, non-owner
|
||||
|
||||
The allocated bit (flag ??????) is believed even if the i-node
|
||||
map says the i-node is free; thus corruption of the map may
|
||||
cause i-nodes to become unallocatable, but will not cause active
|
||||
nodes to be reused.
|
||||
|
||||
Word number n of a file is accessed as follows: n is
|
||||
divided by 64 to find its logical block number (say b) in
|
||||
the file. If the file is small (flag 200000 is 0), then b
|
||||
must be less than 7, and the physical block number corresponding
|
||||
to b is the bth entry in the address portion of the i-node.
|
||||
|
||||
If the file is large, b is divided by 64 to yield a number
|
||||
which must be less than 8 (or the file is too large for
|
||||
UNIX to handle). The corresponding slot in the i-node
|
||||
address portion gives the physical block number of an
|
||||
indirect block. The residue mod 64 gives a word offset
|
||||
in the indirect block, and the word found there is the
|
||||
physical address of the block corresponding to b.
|
||||
|
||||
If block b in a file exists, it is not necessary that all
|
||||
blocks less than b exist. A zero block number either in the
|
||||
address words of the i-node or in an indirect block
|
||||
indicates that the corresponding block has never been
|
||||
allocated. Such a missing block reads as if it contained
|
||||
all zero words.
|
||||
|
||||
FILES
|
||||
|
||||
SEE ALSO format of directories
|
||||
|
||||
DIAGNOSTICS
|
||||
|
||||
BUGS
|
||||
|
||||
OWNER
|
||||
Reference in New Issue
Block a user