772 lines
15 KiB
Text
772 lines
15 KiB
Text
.TH PREP 8
|
||
.SH NAME
|
||
prep, edisk, fdisk, format, mbr \- prepare disks, floppies and flashes
|
||
.SH SYNOPSIS
|
||
.B disk/prep
|
||
[
|
||
.B -bcfnprw
|
||
]
|
||
[
|
||
.B -a
|
||
.I name
|
||
]...
|
||
[
|
||
.B -s
|
||
.I sectorsize
|
||
]
|
||
.I plan9partition
|
||
.PP
|
||
.B disk/edisk
|
||
[
|
||
.B -abfprw
|
||
]
|
||
[
|
||
.B -s
|
||
.I sectorsize
|
||
]
|
||
.I disk
|
||
.PP
|
||
.B disk/fdisk
|
||
[
|
||
.B -abfprw
|
||
]
|
||
[
|
||
.B -s
|
||
.I sectorsize
|
||
]
|
||
.I disk
|
||
.PP
|
||
.B disk/format
|
||
[
|
||
.B -dfvx
|
||
]
|
||
[
|
||
.B -b
|
||
.I bootblock
|
||
]
|
||
[
|
||
.B -c
|
||
.I csize
|
||
]
|
||
[
|
||
.B -l
|
||
.I label
|
||
]
|
||
[
|
||
.B -r
|
||
.I nresrv
|
||
]
|
||
[
|
||
.B -t
|
||
.I type
|
||
]
|
||
.I disk
|
||
[
|
||
.IR file ...
|
||
]
|
||
.PP
|
||
.B disk/mbr
|
||
[
|
||
.B -9
|
||
]
|
||
[
|
||
.B -m
|
||
.I mbrfile
|
||
]
|
||
.I disk
|
||
.SH DESCRIPTION
|
||
A partition table is stored on a hard disk to specify the division of
|
||
the physical disk into a set of logical units.
|
||
On PCs using traditional DOS partition table, the partition entries are stored
|
||
at the end of the master boot record of the disk.
|
||
Partitions of type
|
||
.B 0x39
|
||
are Plan 9 partitions.
|
||
EFI systems use GUID partition table (GPT) format where partition types
|
||
are identied by a 128-bit long identifiers. The randomly
|
||
generated GUID
|
||
.B C91818F9-8025-47AF-89D2-F030D7000C2C
|
||
is used to identify the Plan 9 partition type in this scheme.
|
||
The names of DOS and GPT partitions are chosen by convention from the type:
|
||
.BR dos ,
|
||
.BR plan9 ,
|
||
etc.
|
||
Second and subsequent partitions of the same type on a given disk are given
|
||
unique names by appending a number (or a period and a number if the name
|
||
already ends in a number).
|
||
.PP
|
||
Plan 9 partitions (and Plan 9 disks on non-PCs) are
|
||
themselves divided, using a textual partition table, called the Plan 9 partition table, in the second
|
||
sector of the partition (the first is left for architecture-specific boot data, such as PC boot blocks).
|
||
The table is a sequence of lines of the format
|
||
.BI part " name start end" \fR,
|
||
where
|
||
.I start
|
||
and
|
||
.I end
|
||
name the starting and ending sector.
|
||
Sector 0 is the first sector of the Plan 9 partition or disk,
|
||
regardless of its position in a larger disk.
|
||
Partition extents do not contain the ending sector,
|
||
so a partition from 0 to 5 and a partition from 5 to 10
|
||
do not overlap.
|
||
.PP
|
||
The Plan 9 partition often contains a number of
|
||
conventionally named subpartitions.
|
||
They include:
|
||
.TF arenas
|
||
.TP
|
||
.B 9fat
|
||
A small FAT file system used to hold
|
||
configuration information
|
||
(such as
|
||
.B plan9.ini
|
||
and
|
||
.BR plan9.nvr )
|
||
and kernels.
|
||
This typically begins in the first sector
|
||
of the partition, and contains the partition
|
||
table as a ``reserved'' sector.
|
||
See the discussion of the
|
||
.B -r
|
||
option to
|
||
.IR format .
|
||
.TP
|
||
.B arenas
|
||
A
|
||
.IR venti (8)
|
||
arenas partition.
|
||
.TP
|
||
.B bloom
|
||
A
|
||
.IR venti (8)
|
||
bloom-filter partition.
|
||
.TP
|
||
.B cache
|
||
A
|
||
.IR cfs (4)
|
||
file system cache.
|
||
.TP
|
||
.B fscache
|
||
A
|
||
.IR cwfs (4)
|
||
worm cache partition.
|
||
.TP
|
||
.B fsworm
|
||
A
|
||
.IR cwfs (4)
|
||
worm filesystem.
|
||
.TP
|
||
.B fs
|
||
A kfs file system.
|
||
.TP
|
||
.B fscfg
|
||
A one-sector partition used to store an
|
||
.IR fs (3)
|
||
configuration.
|
||
.TP
|
||
.B isect
|
||
A
|
||
.IR venti (8)
|
||
index section.
|
||
.TP
|
||
.B nvram
|
||
A one-sector partition used to simulate non-volatile RAM on PCs.
|
||
.TP
|
||
.B other
|
||
A non-archived
|
||
.IR cwfs (4)
|
||
file system.
|
||
.TP
|
||
.B swap
|
||
A
|
||
.IR swap (8)
|
||
swap partition.
|
||
.PD
|
||
.PP
|
||
.I Fdisk
|
||
edits the DOS partition table and is usually
|
||
invoked with a disk like
|
||
.B /dev/sdC0/data
|
||
as its argument, while
|
||
.I prep
|
||
edits the Plan 9 partition table
|
||
and is usually invoked with a disk partition
|
||
like
|
||
.B /dev/sdC0/plan9
|
||
as its argument.
|
||
.I Edisk
|
||
is similar to
|
||
.I fdisk
|
||
but edits the GPT partition table on EFI systems.
|
||
.I Fdisk
|
||
works in units of disk ``cylinders'': the cylinder
|
||
size in bytes is printed when
|
||
.I fdisk
|
||
starts.
|
||
.I Prep
|
||
and
|
||
.I edisk
|
||
works in units of disk sectors, which are almost always 512 bytes.
|
||
.IR Fdisk ,
|
||
.I edisk
|
||
and
|
||
.I prep
|
||
share most of their options:
|
||
.TF -a
|
||
.PD
|
||
.TP
|
||
.B -a
|
||
Automatically partition the disk.
|
||
.I Fdisk
|
||
and
|
||
.I edisk
|
||
will create a Plan 9
|
||
partition in the largest unused area on the disk,
|
||
doing nothing if a
|
||
Plan 9 partition already exists.
|
||
.I Edisk
|
||
also adds a EFI system partition (esp) when not already exists.
|
||
If no other partition on the disk is marked active (i.e. marked as the boot partition),
|
||
.I fdisk
|
||
will mark the new partition active.
|
||
.IR Prep 's
|
||
.B -a
|
||
flag takes the name of a partition to create.
|
||
(See the list above for partition names.)
|
||
It can be repeated to specify a list of partitions to create.
|
||
If the disk is currently unpartitioned,
|
||
.I prep
|
||
will create the named partitions on the disk,
|
||
attempting to use the entire disk in a sensible manner.
|
||
The partition names must be from the list given above.
|
||
.TP
|
||
.B -b
|
||
Start with a blank disk, ignoring any extant partition table.
|
||
.TP
|
||
.B -p
|
||
Print a sequence of commands that when sent to the disk device's
|
||
.B ctl
|
||
file
|
||
will bring the partition
|
||
table information kept by
|
||
the
|
||
.IR sd (3)
|
||
driver up to date.
|
||
Then exit.
|
||
.I Prep
|
||
will check to see if it is being called with a disk partition
|
||
(rather than an entire disk) as its argument; if so, it
|
||
will translate the printed sectors by the partition's offset
|
||
within the disk.
|
||
Since
|
||
.I fdisk
|
||
and
|
||
.I edisk
|
||
operate on a table of unnamed partitions,
|
||
they assign names based on the partition type
|
||
(e.g.,
|
||
.BR plan9 ,
|
||
.BR dos ,
|
||
.BR ntfs ,
|
||
.BR linux ,
|
||
.BR linuxswap )
|
||
and resolve collisions by appending a numbered suffix.
|
||
(e.g.,
|
||
.BR dos ,
|
||
.BR dos.1 ,
|
||
.BR dos.2 ).
|
||
.TP
|
||
.B -r
|
||
In the absence of the
|
||
.B -p
|
||
and
|
||
.B -w
|
||
flags,
|
||
.IR prep ,
|
||
.I edisk
|
||
and
|
||
.I fdisk
|
||
enter an interactive partition editor;
|
||
the
|
||
.B -r
|
||
flag runs the editor in read-only mode.
|
||
.TP
|
||
.BI -s " sectorsize"
|
||
Specify the disk's sector size.
|
||
In the absence of this flag,
|
||
.IR prep ,
|
||
.I edisk
|
||
and
|
||
.I fdisk
|
||
look for a disk
|
||
.B ctl
|
||
file and read it to find the disk's sector size.
|
||
If the
|
||
.B ctl
|
||
file cannot be found, a message is printed and
|
||
a sector size of 512 bytes is assumed.
|
||
.TP
|
||
.B -w
|
||
Write the partition table to the disk and exit.
|
||
This is useful when used in conjunction with
|
||
.B -a
|
||
or
|
||
.BR -b .
|
||
.PP
|
||
If neither the
|
||
.B -p
|
||
flag nor the
|
||
.B -w
|
||
flag is given,
|
||
.IR prep ,
|
||
.I edisk
|
||
and
|
||
.I fdisk
|
||
enter an interactive partition editor that
|
||
operates on named partitions.
|
||
The DOS partition table distinguishes between
|
||
primary partitions, which can be listed in the boot
|
||
sector at the beginning of the disk,
|
||
and secondary (or extended) partitions, arbitrarily
|
||
many of which may be chained together in place
|
||
of a primary partition.
|
||
Primary partitions are named
|
||
.BR p \fIn\fR,
|
||
secondary partitions
|
||
.BR s \fIn\fR.
|
||
The number of primary partitions plus number of contiguous chains of
|
||
secondary partitions cannot exceed four.
|
||
The GPT partition table is a fixed array of partition
|
||
entries (usually 128). Partitions are named
|
||
.BR p \fIn\fR,
|
||
where
|
||
.I n
|
||
indexes the entry in array starting from 1 for the first entry.
|
||
.PP
|
||
The commands are as follows.
|
||
In the descriptions, read ``sector'' as ``cylinder'' when using
|
||
.IR fdisk .
|
||
.TF ".\fI newdot
|
||
.PD
|
||
.TP
|
||
.B "a\fR \fIname\fR [ \fIstart\fR [ \fIend\fR ] ]"
|
||
Create a partition named
|
||
.I name
|
||
starting at sector offset
|
||
.I start
|
||
and ending at offset
|
||
.IR end .
|
||
The new partition will not be created if
|
||
it overlaps an extant partition.
|
||
If
|
||
.I start
|
||
or
|
||
.I end
|
||
are omitted, the editor will prompt for them.
|
||
In
|
||
.I fdisk
|
||
and
|
||
.I edisk
|
||
the newly created partition is of the
|
||
.B Plan 9
|
||
type; to set a different type, use the
|
||
.B t
|
||
command (q.v.).
|
||
.I Start
|
||
and
|
||
.I end
|
||
may be expressions using the operators
|
||
.BR + ,
|
||
.BR - ,
|
||
.BR * ,
|
||
and
|
||
.BR / ,
|
||
numeric constants, and the
|
||
pseudovariables
|
||
.B .
|
||
and
|
||
.BR $ .
|
||
At the start of the program,
|
||
.B .
|
||
is set to zero; each time a partition is
|
||
created, it is set to the end sector
|
||
of the new partition.
|
||
It can also be explicitly set using the
|
||
.B .
|
||
command.
|
||
When evaluating
|
||
.IR start ,
|
||
.B $
|
||
is set to one past the last disk sector.
|
||
When evaluating
|
||
.IR end ,
|
||
.B $
|
||
is set to the maximum value that
|
||
.I end
|
||
can take on without running off the disk
|
||
or into another partition.
|
||
Numeric constants followed by
|
||
.LR k ,
|
||
.LR m ,
|
||
.LR g ,
|
||
or
|
||
.LR t
|
||
(or upper-case equivalents)
|
||
are scaled to the respective size in kilo-, mega-, giga-, or tera-bytes.
|
||
Finally, the expression
|
||
.IB n %
|
||
evaluates to
|
||
.RI ( n × disksize )/100.
|
||
As examples,
|
||
.L "a . .+20%"
|
||
creates a new partition starting at
|
||
.B .
|
||
that takes up a fifth of the disk,
|
||
.L "a . .+21G"
|
||
creates a new partition starting at
|
||
.B .
|
||
that takes up 21 gigabytes (21×2\u\s-130\s0\d bytes),
|
||
and
|
||
.L "a 1000 $"
|
||
creates a new partition starting at
|
||
sector 1000 and
|
||
extending as far as possible.
|
||
.TP
|
||
.B ".\fR \fInewdot"
|
||
Set the value of the variable
|
||
.B .
|
||
to
|
||
.IR newdot ,
|
||
which is an arithmetic expression as described
|
||
in the discussion of the
|
||
.B a
|
||
command.
|
||
.TP
|
||
.BI d " name"
|
||
Delete the named partition.
|
||
.TP
|
||
.B h
|
||
Print a help message listing command synopses.
|
||
.TP
|
||
.B p
|
||
Print the disk partition table.
|
||
Unpartitioned regions are also listed.
|
||
The table consists of a number of lines containing
|
||
partition name, beginning and ending sectors,
|
||
and total size.
|
||
A
|
||
.B '
|
||
is prefixed to the names of partitions
|
||
whose entries have been modified but not written to disk.
|
||
.I Fdisk
|
||
adds to the end of each line a textual partition type,
|
||
and places a
|
||
.B *
|
||
next to the name of the active partition
|
||
(see the
|
||
.B A
|
||
command below).
|
||
.TP
|
||
.B P
|
||
Print the partition table in the format accepted by the disk's
|
||
.B ctl
|
||
file, which is also the format of the output of the
|
||
.B -p
|
||
option.
|
||
.TP
|
||
.B w
|
||
Write the partition table to disk.
|
||
.I Prep
|
||
will also inform the kernel of the changed
|
||
partition table.
|
||
The write will fail if any programs have any
|
||
of the disk's partitions open.
|
||
If the write fails (for this or any other reason),
|
||
the program will attempt to restore the partition table to
|
||
its former state.
|
||
.TP
|
||
.B q
|
||
Quit the program.
|
||
If the partition table has been modified but not written,
|
||
a warning is printed.
|
||
Typing
|
||
.B q
|
||
again will quit the program.
|
||
.PP
|
||
.I Fdisk
|
||
also has the following commands.
|
||
.TF "t \fR[\fI type \fR]
|
||
.PD
|
||
.TP
|
||
.BI A " name
|
||
Set the named partition active.
|
||
The active partition is the one whose boot block is used
|
||
when booting a PC from disk.
|
||
.TP
|
||
.BI t " name \fR[\fI type \fR]
|
||
Set the partition type. If it is not given,
|
||
.I fdisk
|
||
will display a list of choices and then prompt for it.
|
||
.PD
|
||
.PP
|
||
.I Edisk
|
||
also has the following commands.
|
||
.TF "t \fR[\fI type \fR]
|
||
.PD
|
||
.TP
|
||
.BI t " name \fR[\fI type \fR]
|
||
Set the partition type; like
|
||
.I fdisk
|
||
above.
|
||
.PD
|
||
.TP
|
||
.BI f " name \fR[\fI +-attr \fR]
|
||
Set or clear partition attributes.
|
||
.PD
|
||
.TP
|
||
.BI l " name \fR[\fI label \fR]
|
||
Set the partition label.
|
||
.PP
|
||
.I Format
|
||
prepares for use the floppy diskette or hard disk partition in the file named
|
||
.IR disk ,
|
||
for example
|
||
.B /dev/fd0disk
|
||
or
|
||
.BR /dev/sdC0/9fat .
|
||
The options are:
|
||
.TP
|
||
.B -f
|
||
Do not physically format the disc. Used
|
||
to install a FAT file system on a
|
||
previously formatted disc. If
|
||
.I disk
|
||
is not a floppy device, this flag is a no-op.
|
||
.TP
|
||
.B -t
|
||
specify a density and type of disk to be prepared.
|
||
The possible
|
||
.I types
|
||
are:
|
||
.RS
|
||
.TP
|
||
.B 3½DD
|
||
3½" double density, 737280 bytes
|
||
.TP
|
||
.B 3½HD
|
||
3½" high density, 1474560 bytes
|
||
.TP
|
||
.B 5¼DD
|
||
5¼" double density, 368640 bytes
|
||
.TP
|
||
.B 5¼HD
|
||
5¼" high density, 1146880 bytes
|
||
.TP
|
||
.B hard
|
||
fixed disk
|
||
.PD
|
||
.PP
|
||
The default when
|
||
.I disk
|
||
is a floppy drive is the highest possible on the device.
|
||
When
|
||
.I disk
|
||
is a regular file, the default is
|
||
.BR 3½HD .
|
||
When
|
||
.I disk
|
||
is an
|
||
.IR sd (3)
|
||
device, the default is
|
||
.BR hard .
|
||
.RE
|
||
.TP
|
||
.B -d
|
||
initialize a FAT file system on the
|
||
.IR disk .
|
||
.TP
|
||
.B -b
|
||
use the contents of
|
||
.I bootblock
|
||
as a bootstrap block
|
||
to be installed in sector 0.
|
||
.PD
|
||
.PP
|
||
The remaining options have effect only when
|
||
.B -d
|
||
is specified:
|
||
.TP
|
||
.B -c
|
||
use a FAT cluster size of
|
||
.I csize
|
||
sectors when creating the FAT.
|
||
.TP
|
||
.B -l
|
||
add a
|
||
.I label
|
||
when creating the FAT file system.
|
||
.TP
|
||
.BI -r
|
||
mark the first
|
||
.I nresrv
|
||
sectors of the partition as ``reserved''.
|
||
Since the first sector always contains the
|
||
FAT parameter block, this really marks
|
||
the
|
||
.IR nresrv -1
|
||
sectors starting at sector 1 as ``reserved''.
|
||
When formatting the
|
||
.B 9fat
|
||
partition,
|
||
.B -r
|
||
.B 2
|
||
should be used to jump over the partition table sector.
|
||
.PD
|
||
.PP
|
||
Again under
|
||
.BR -d ,
|
||
any
|
||
.I files
|
||
listed are added, in order,
|
||
to the root
|
||
directory of the FAT file system. The files are
|
||
contiguously allocated.
|
||
.PP
|
||
.I Format
|
||
checks for a number of common mistakes; in particular,
|
||
it will refuse to format a
|
||
.B 9fat
|
||
partition unless
|
||
.B -r
|
||
is specified with
|
||
.I nresrv
|
||
larger than two.
|
||
It also refuses to format a raw
|
||
.IR sd (3)
|
||
partition that begins at offset zero in the disk.
|
||
(The beginning of the disk should contain an
|
||
.I fdisk
|
||
partition table with master boot record,
|
||
not a FAT file system or boot block.)
|
||
Both checks are disabled by the
|
||
.B -x
|
||
option.
|
||
The
|
||
.B -v
|
||
option prints debugging information.
|
||
.PP
|
||
The file
|
||
.B /386/pbs
|
||
is an example of a suitable
|
||
.I bfile
|
||
to make the disk a boot disk.
|
||
It gets loaded by the BIOS at 0x7C00,
|
||
reads the first sector of the
|
||
root directory into address 0x7E00, and looks for
|
||
a directory entry named
|
||
.BR 9BOOTFAT .
|
||
If it finds such an entry,
|
||
it uses
|
||
single sector reads to load the file into address 0x7C00 and then
|
||
jumps to the loaded file image.
|
||
.PP
|
||
.I Mbr
|
||
installs a new boot block in sector 0 (the master boot record)
|
||
of a disk such as
|
||
.BR /dev/sdC0/data .
|
||
If
|
||
.I mbrfile
|
||
contains more than one sector of `boot block',
|
||
the rest will be copied into the first track of the
|
||
disk, if it fits.
|
||
This boot block should not be confused with the
|
||
boot block used by
|
||
.IR format ,
|
||
which goes in sector 0 of a partition.
|
||
Typically, the boot block in the master boot record
|
||
scans the PC partition table to find an active
|
||
partition and then executes the boot block for
|
||
that partition.
|
||
The partition boot block then loads a bootstrap
|
||
program such as
|
||
.IR 9boot (8),
|
||
which then loads the operating system.
|
||
If MS-DOS or Windows 9[58] is already installed
|
||
on your hard disk, the master boot record
|
||
already has a suitable boot block.
|
||
Otherwise,
|
||
.B /386/mbr
|
||
is an appropriate
|
||
.IR mbrfile .
|
||
It detects and uses LBA addressing when available
|
||
from the BIOS (the same could not
|
||
be done in the case of
|
||
.B pbs
|
||
due to space considerations).
|
||
If the
|
||
.I mbrfile
|
||
is not specified, a boot block is installed that
|
||
prints a message explaining that the disk is not bootable.
|
||
The
|
||
.B -9
|
||
option initialises the partition table to consist of one
|
||
.BR plan9
|
||
partition which spans the entire disc starting at the end of the
|
||
first track.
|
||
.SH EXAMPLES
|
||
Initialize the kernel disk driver with the partition information
|
||
from the FAT boot sectors.
|
||
If Plan 9 partitions exist, pass that partition information as well.
|
||
.IP
|
||
.EX
|
||
for(disk in /dev/sd??) {
|
||
if(test -f $disk/data && test -f $disk/ctl)
|
||
disk/fdisk -p $disk/data >$disk/ctl
|
||
for(part in $disk/plan9*)
|
||
if(test -f $part)
|
||
disk/prep -p $part >$disk/ctl
|
||
}
|
||
.EE
|
||
.PP
|
||
Initialize the blank hard disk
|
||
.BR /dev/sdC0/data .
|
||
.IP
|
||
.EX
|
||
disk/mbr -m /386/mbr /dev/sdC0/data
|
||
disk/fdisk -baw /dev/sdC0/data
|
||
disk/prep -bw -a^(9fat nvram fscache fsworm other swap) /dev/sdC0/plan9
|
||
disk/format -b /386/pbs -d -r 2 /dev/sdC0/9fat \e
|
||
/386/9bootfat /386/9pc /tmp/plan9.ini
|
||
.EE
|
||
.SH FILES
|
||
.TP
|
||
.B /386/mbr
|
||
.TP
|
||
.B /386/pbs
|
||
.SH SOURCE
|
||
.TF /sys/src/cmd/disk/prep
|
||
.TP
|
||
.B /sys/src/cmd/disk/prep
|
||
.TP
|
||
.B /sys/src/boot/pc
|
||
.SH SEE ALSO
|
||
.IR floppy (3),
|
||
.IR sd (3),
|
||
.IR nusb (4),
|
||
.IR 9boot (8),
|
||
.IR partfs (8),
|
||
.IR diskparts (8)
|
||
.SH BUGS
|
||
If
|
||
.L "prep -p"
|
||
doesn't find a Plan 9 partition table,
|
||
it will emit commands to delete
|
||
.I all
|
||
extant partitions.
|
||
Similarly,
|
||
.L "fdisk -p"
|
||
will delete all partitions,
|
||
including
|
||
.LR data ,
|
||
if there are no partitions defined in the MBR.
|