NAME
sunlabel —
read or modify a SunOS disk
label
SYNOPSIS
DESCRIPTION
sunlabel reads or modifies a SunOS disk label on
device, which is used by the PROM on
NetBSD/sparc hardware to find partitions to boot from.
sunlabel only reads/writes the first 512 bytes of
device.
The supported options are:
-
-
- -m
- Ignore an incorrect magic number in the disk label.
-
-
- -n
- Synthesize a new label rather than reading what is
there.
-
-
- -q
- Quiet mode - don't print unnecessary babble (currently this
suppresses the “sunlabel>” prompt).
-
-
- -s
- Ignore checksum errors when reading the label.
Note that
-m is dangerous, especially when combined with
-s, since it will then happily believe whatever garbage it
may find in the label. When using these flags, all values should be checked
carefully, both those printed by
L and the partition table
printed by
P.
sunlabel prints a prompt “sunlabel>” and
expects commands. The following commands are understood:
-
-
- ?
- Show a short help message.
-
-
- [abcdefghijklmnop]
<cylno> <size>
- Change partition (see below).
-
-
- L
- Print label, except for the partition table.
-
-
- P
- Print the partition table.
-
-
- Q
- Quit program (error if no write since last change).
-
-
- Q!
- Quit program (unconditionally) [EOF also quits].
-
-
- S
- Set label in the kernel (orthogonal to
W).
-
-
- V
<name> <value>
- Change a non-partition label value.
-
-
- W
- Write (possibly modified) label out.
The
a through
p commands will accept, for
the
<size> parameter, the
nnn/nnn/nnn syntax used by SunOS 4.x
format. (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
-n 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 space in the Sun label format.
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
V ncyl 6204 would set the
ncyl value to 6204, or
V
ascii Seagate ST15230N cyl 5657 hd 19 sec varying would
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.
AUTHORS
der Mouse
<
mouse@rodents.montreal.qc.ca>
BUGS
It may be that the space in the label where the information for the extended
partitions is saved is used by SunOS.
Not very many consistency checks are done on the
V arguments,
and those only produce warnings.
NetBSD doesn't support 16 partitions in a Sun disk label
yet.