Added a description of SUN Disk Label for SUN SPARC machines.

doc/boot_sectors.txt

@@ -23,6 +23,8 @@ MIPS Volume Header, for MIPS Big Endian, e.g. SGI Indigo2.
 
 DEC Boot Block, for MIPS Little Endian , e.g. DECstation.
 
+SUN Disk Label and boot images, for SUN SPARC
+
 
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@@ -648,6 +650,109 @@ Byte Range | Value      | Meaning
   16 -  19 |   p_filesz | /* Segment size in file */
            |-> seg_size | Needed for seg_size
            |            |
+---------- | ---------- | ----------------------------------------------------
+
+
+------------------------------------------------------------------------------
+
+
+                          SUN Disk Label and boot images
+                                 for SUN SPARC
+
+Sources:
+   cdrtools-2.01.01a77/mkisofs/sunlabel.h
+   cdrtools-2.01.01a77/mkisofs/mkisofs.8
+   by Joerg Schilling
+
+
+The Disk Label is written to the first 512 bytes of the image. It can mark
+8 partitions (slices ) of which the first contains the ISO image. The other
+7 may contain boot images.
+Words are composed big-endian style.
+
+Boot images are provided externally. mkisofs arranges them after the end of
+the ISO image so that each starts at a cylinder boundary (320 kB).
+
+There is a mechanism in mkisofs which fills unused partitions by copies of
+their predecessor in the partition table:
+"If the special filename ... is used, the actual and all following
+ boot partitions are mapped to  the  previous  partition.
+ If mkisofs is called with -G image -B ... all boot partitions are
+ mapped to the partition that contains the ISO9660 filesystem."
+
+
+Disk Label components:
+
+Byte Range | Value      | Meaning
+---------- | ---------- | ----------------------------------------------------
+   0 - 127 |      label | ASCII Label
+           |            | "CD-ROM Disc with Sun sparc boot created by ..."
+           |            | mkisofs option -sparc-label
+           |            |
+ 128 - 263 | ========== | /* vtoc inclusions from AT&T SVr4 */
+           |            |
+ 128 - 131 |          1 | Layout version
+ 132 - 139 |          0 | /* volume name           */
+ 140 - 141 |          8 | Number of partitions
+           |            |
+ 142 - 173 | ========== | 8 partition entries of 4 bytes
+           |            |
+ 142 - 145 | ========== | Entry for partition 1
+ 142 - 143 |          4 | ID tag of partition: 4 = User partition
+ 144 - 145 |       0x10 | Permissions: 0x10 = read-only
+           |            |
+ 146 - 149 | ========== | Entry for partition 2 
+ 146 - 147 |    id_tag2 | ID tag of partition:
+           |            | 0 = unused
+           |            | 2 = Root partition with boot image
+ 148 - 149 |      perm2 | Permissions:
+           |            | 0 = unused
+           |            | 0x10 = read-only (if used)
+           |            |
+ 150 - 173 | ========== | Entries for partition 3 to 8.
+           |            | See above: Entry for partition 2
+           |            |
+ 174 - 175 |          0 | Padding
+           |            |
+ 176 - 187 |          0 | /* info for mboot       */
+           |            |
+ 188 - 191 | 0x600ddeee | /* to verify vtoc sanity */
+           |            |
+ 192 - 231 |          0 | Reserved
+           |            |
+ 232 - 263 |          0 | 8 Timestamps of yet unknown format
+           |            |
+ 264 - 419 |          0 | Padding
+           |            |
+ 420 - 443 | ========== | Disk properties
+           |            |
+ 420 - 421 |        350 | Rotations per minute
+ 422 - 423 |       2048 | Number of physical cylinders (fixely 640 MB)
+ 424 - 425 |          0 | /* alternates per cylinder */
+ 426 - 429 |          0 | /* obsolete */
+ 430 - 431 |          1 | /* interleave factor */
+ 432 - 433 |       2048 | Number of data cylinders (fixely 640 MB)
+ 434 - 435 |          0 | /* # of alternate cylinders */
+ 436 - 437 |          1 | Number of heads per cylinder (i.e. 1 cyl = 320 kB)
+ 438 - 439 |        640 | Number of sectors per head (i.e. 1 head = 320 kB)
+ 440 - 443 |          0 | /* obsolete */
+           |            |
+ 444 - 507 | ========== | Partition table
+           |            |
+ 444 - 451 | ========== | Partition table entry #1
+           |            |
+ 444 - 447 |  start_cyl | Start cylinder
+           |            |
+ 448 - 451 | num_blocks | Number of blocks in partition
+           |            |
+ 452 - 507 | ========== | Partition table entries #2 to #8
+           |        ... | See above Partition table entry #1
+           |            |
+ 508 - 509 |     0xdabe | Magic Number
+           |            |
+ 510 - 511 |   checksum | The result of exoring 2-byte words 0 to 254
+           |            |
+---------- | ---------- | ----------------------------------------------------
 
 
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