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der Mouse's sunlabel.doc

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1 parent a65afea commit 77ba051b6cd10573e67a901c0357432037443026 mrg committed Jan 10, 2002
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+sunlabel.c is the source. It should build Just Fine on any NetBSD
+machine; with -DDISTRIB, probably on many non-NetBSD machines - though
+it may require a little tweaking on some. It should work on both
+big-endian and little-endian machines; though I have not personally
+tried it on anything but SPARC and sun3, I have heard one report that
+it worked on NetBSD/i386, which is little-endian.
+
+Usage: pass a single argument, which is the disk device or file you
+wish to read/write the label to/from. sunlabel reads/writes only the
+first 512 bytes of its argument. There are also some flags supported:
+
+ -disk
+ takes an argument specifying the disk device (in case
+ you want to give something beginning with a -)
+ -fixmagic
+ says to ignore an incorrect magic number in the disk
+ label
+ -fixsum
+ says to ignore checksum errors when reading the label
+ -new
+ says to synthesize a new label rather than reading
+ what's there
+ -q
+ quiet mode - don't print unnecessary babble (currently
+ this suppresses the "sunlabel>" prompt).
+
+Note that -fixmagic is dangerous, especially when combined with
+-fixsum, since it will then happily believe whatever garbage it may
+find in the label. If you use these, you should check all values
+carefully, both the values printed by L and the partition table printed
+by P.
+
+sunlabel prints a prompt "sunlabel>" and expects commands. You can
+type ? for help; as of this writing, the help is
+
+ ? - print this help
+ L - print label, except for partition table
+ P - print partition table
+ [abcdefghijklmnop] <cylno> <size> - change partition
+ V <name> <value> - change a non-partition label value
+ W - write (possibly modified) label out
+ S - set label in the kernel (orthogonal to W)
+ Q - quit program (error if no write since last change)
+ Q! - quit program (unconditionally) [EOF also quits]
+
+(If built without special precautions, the S line is present only when
+built on NetBSD.)
+
+The a through p commands will accept, for the <size> parameter, the
+nnn/nnn/nnn syntax used by SunOS 4.x format(8). (For those not
+familiar with this syntax, a/b/c means a cylinders + b tracks + c
+sectors. For example, if the disk has 16 tracks of 32 sectors, 3/4/5
+means (3*16*32)+(4*32)+5=1669. This calculation always uses the nsect
+and ntrack values as printed by the L command; in particular, if they
+are zero (which they will initially be if -new is used), this syntax is
+not very useful. Some additional strings are accepted. For the
+<cylno> parameter, "end-X" (where X is a partition letter) indicates
+that the partition should start with the first free cylinder after
+partition X; "start-X" indicates that the partition should start at the
+same place as partition X. For the <size> parameter, "end-X" indicates
+that the partition should end at the same place as partition X (even if
+partition X ends partway through a cylinder); "start-X" indicates that
+the partition should end with the last cylinder before partition X; and
+"size-X" means that the partition's size should exactly match partition
+X's size.
+
+Note that sunlabel supports 16 partitions. SunOS supports only 8.
+Labels written by sunlabel, when partitions i through p are all set
+offset=0 size=0, are identical to Sun labels. If any of the "extended"
+partitions are nontrivial, information about them is tucked into some
+otherwise unused (as far as I can tell) space in the Sun label format.
+I don't know whether SunOS cares what's in that space; as far as I know
+only NetBSD actually uses the extended information, and even that only
+with my patches to do so.
+
+The V command changes fields printed by the L command. For example, if
+the L command prints
+
+ ascii: ST15230N cyl 5657 alt 2 hd 19 sec 78
+ rpm: 0 pcyl: 0 apc: 0 obs1: 0
+ obs2: 0 intrlv: 1 ncyl: 5657 acyl: 0
+ nhead: 19 nsect: 78 obs3: 0 obs4: 0
+
+then you could type "V ncyl 6204" to set the ncyl value to 6204, or
+"V ascii Seagate ST15230N cyl 5657 hd 19 sec varying" to set the
+ascii-label string to that string. sunlabel performs very few
+consistency checks on the values you supply, and the ones it does
+perform never generate errors, only warnings; it's a YAFIYGI program.
+
+I will be glad to correspond with anyone about this program. I'm...
+
+ der Mouse
+
+ mouse@rodents.montreal.qc.ca
+ 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

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