fs.5: format under UNIX-7 roff!

mention boot & swap track locations

man/fs.5

@@ -4,14 +4,18 @@ NAME	format of file system
 .sp
 SYNOPSIS	--
 .sp
-DESCRIPTION	The RB09 fixed head disk has 8,000 64-word
+DESCRIPTION
-	blocks on each of its two surfaces. Unix uses
+.in 8
+The RB09 fixed head disk has 8,000 64-word
+blocks (100 tracks of 80 bloocks)
+on each of its two surfaces. The Unix filesystem
+is stored in the first 80 tracks of
 the second surface (physical blocks 8,000 to
-	15,999) and numbers them from logical block 0 to
+14,399 -- physical tracks 100 to 179)
-	logical block 7,999. The following discussion
+and numbers them from logical block 0 to
-	refers to logical blocks.
+logical block 6,399.
 .sp
-	The Unix filesystem is divided into 8,000 blocks
+The Unix filesystem is divided into 6,400 logical 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
@@ -26,44 +30,56 @@ DESCRIPTION	The RB09 fixed head disk has 8,000 64-word
 .sp
 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
+contain the i-nodes, with five 12-word
 i-nodes per block. Certain i-nodes are reserved
 for special files, directories and devices:
 .sp
-		1	The core file written by "sys save" or a
+.nf
-			bad system call
+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
+7	The "keyboard" (GRAPHIC-2)
-		8	The "pptin" (paper tape reader) special
+	special file
-			file
+8	The "pptin" (paper tape reader)
+	special file
 10	The "ttyout" special file
-		11	The "display" (graphic-2) special file
+11	The "display" (GRAPHIC-2)
-		12	The "pptout" (paper tape punch) special
+	special file
-			file
+12	The "pptout" (paper tape punch)
+	special file
+.fi
 .sp
 There is only one file system which is always
-	mounted; it resides on the RB disk. This device
+mounted; it resides on the RB disk.
-	is also used for swapping. The swap areas are at
+.sp
-	the high blocks on this device: blocks 6,400 to
+The last twenty tracks of the second disk surface
-	7,999. These blocks do not appear in the free
+are use for bootable images and swapping:
-	list.
+.sp
+Each physical track from 180 to 189
+contains a bootable system image of 3K words.
+.sp
+Each physical track from 190 to 199 is used to swap
+a user process (4K words plus a 64-word swapable
+"userdata" area).
 .sp
 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:
 .sp
+.nf
 0	flags (see below)
-		1	first indirect block or contents block
+1	first indirect block or data block
 ...
-		7	seventh indirect block or contents block
+7	seventh indirect block or data block
 8	user ID of owner
 9	link count
 10	size in words
 11	unique value assigned at creation
 .sp
+.in 8
 The flags are as follows:
 .sp
 400000   i-node is allocated
@@ -75,6 +91,8 @@ DESCRIPTION	The RB09 fixed head disk has 8,000 64-word
 000004   write, owner
 000002   read, non-owner
 000001   write, non-owner
+.fi
+.in 8
 .sp
 The allocated bit (flag ??????) is believed even
 if the i-node map says the i-node is free; thus
@@ -107,6 +125,7 @@ DESCRIPTION	The RB09 fixed head disk has 8,000 64-word
 corresponding block has never been allocated.
 Such a missing block reads as if it contained
 all zero words.
+.in 0
 .sp
 FILES	--
 .sp