illumos: manual page: mkfs

MKFS_PCFS(8) Maintenance Procedures MKFS_PCFS(8)

NAME

mkfs_pcfs - construct a FAT file system

SYNOPSIS

mkfs -F pcfs [generic_options] [-o FSType_specific_options] raw_device_file

DESCRIPTION

The pcfs-specific module of mkfs constructs a File Allocation Table (FAT)
on removable media (diskette, JAZ disk, ZIP disk, PCMCIA card), a hard
disk, or a file (see NOTES). FATs are the standard MS-DOS and Windows
file system format. Note that you can use fdformat(1) to construct a FAT
file system only on a diskette or PCMCIA card.

mkfs for pcfs determines an appropriate FAT size for the medium, then it
installs an initial boot sector and an empty FAT. A sector size of 512
bytes is used. mkfs for pcfs can also install the initial file in the
file system (see the pcfs-specific -o i option). This first file can
optionally be marked as read-only, system, and/or hidden.

If you want to construct a FAT with mkfs for pcfs on a medium that is not
formatted, you must first perform a low-level format on the medium with
fdformat(1) or format(8). Non-diskette media must also be partitioned
with the fdisk(8) utility. Note that all existing data on the diskette or
disk partition, if any, is destroyed when a new FAT is constructed.

generic_options are supported by the generic mkfs command. See mkfs(8)
for a description of these options.

raw_device_file indicates the device on which to write unless the -o N
option has been specified, or if the -V or -m generic options are passed
from the generic mkfs module.

OPTIONS

See mkfs(8) for the list of supported generic options.

The following options are supported:

-o FSType_specific_options
Specify pcfs file system-specific options
in a comma-separated list with no
intervening spaces. If invalid options are
specified, a warning message is printed and
the invalid options are ignored.

b=label
Label the media with volume
label. The volume label is
restricted to 11 uppercase
characters.

B=filename
Install filename as the boot
loader in the file system's
boot sector. If you don't
specify a boot loader, an MS-
DOS boot loader is installed.
The MS-DOS boot loader
requires specific MS-DOS
system files to make the
diskette bootable. See NOTES
for more information.

fat=n
The size of a FAT entry.
Currently, 12, 16, and 32 are
valid values. The default is
12 for diskettes, 16 for
larger media.

h
Mark the first file installed
as a hidden file. The -i
option must also be
specified.

hidden=n
Set the number of hidden
sectors to n. This is the
number of sectors on the
physical disk preceding the
start of the volume (which is
the boot sector itself). This
defaults to 0 for diskettes
or a computed valued (based
on the fdisk table) for
disks. This option may be
used only in conjunction with
the nofdisk option.

i=filename
Install filename as the
initial file in the new file
system. The initial file's
contents are guaranteed to
occupy consecutive clusters
at the start of the files
area. When creating bootable
media, a boot program should
be specified as the initial
file.

nofdisk
Do not attempt to find an
fdisk table on the medium.
Instead rely on the size
option for determining the
partition size. By default,
the created FAT is 16 bits
and begins at the first
sector of the device. This
origination sector can be
modified with the hidden
option (-h).

nsect=n
The number of sectors per
track on the disk. If not
specified, the value is
determined by using a
dkio(4I) ioctl to get the
disk geometry, or (for
diskette) from the results of
an FDIOGCHAR ioctl.

ntrack=n
The number of tracks per
cylinder on the disk. If not
specified, the value is
determined by using a
dkio(4I) ioctl to get the
disk geometry, or (for
diskette) from the results of
an FDIOGCHAR ioctl.

N
No execution mode. Print
normal output, but do not
actually write the file
system to the medium. This is
most useful when used in
conjunction with the verbose
option.

r
Mark the first file installed
as read-only. The -i option
must also be specified.

reserve=n
Set the number of reserved
sectors to n. This is the
number of sectors in the
volume, preceding the start
of the first FAT, including
the boot sector. The value
should always be at least 1,
and the default value is
exactly 1.

s
Mark the first file installed
as a system file. The -i
option must also be
specified.

size=n
The number of sectors in the
file system. If not
specified, the value is
determined from the size of
the partition given in the
fdisk table or (for diskette)
by way of computation using
the FDIOGCHAR ioctl.

spc=n
The size of the allocation
unit for space within the
file system, expressed as a
number of sectors. The
default value depends on the
FAT entry size and the size
of the file system.

v
Verbose output. Describe, in
detail, operations being
performed.

FILES

raw_device_file
The device on which to build the FAT. The device name
for a diskette must be specified as /dev/rdiskette0
for the first diskette drive, or /dev/rdiskette1 for a
second diskette drive. For non-diskette media, a disk
device name must be qualified with a suffix to
indicate the proper partition. For example, in the
name /dev/rdsk/c0t0d0p0:c, the :c suffix indicates
that the first partition on the disk should receive
the new FAT.

For a file, raw_device_file is the block device name
returned by lofiadm(8).

EXAMPLES

The media in these examples must be formatted before running mkfs for
pcfs. See DESCRIPTION for more details.

Example 1: Creating a FAT File System on a Diskette

The following command creates a FAT file system on a diskette:

mkfs -F pcfs /dev/rdiskette

Example 2: Creating a FAT File System on a Disk

The following command creates a FAT file system on the second fdisk
partition of a disk attached to an x86 based system:

mkfs -F pcfs /dev/rdsk/c0d0p0:d

Example 3: Creating a FAT File System on a ZIP Disk

The following command creates a FAT file system on a ZIP disk located on
a SPARC based system:

mkfs -F pcfs /dev/rdsk/c0t4d0s2:c

Example 4: Creating a FAT File System on a JAZ Disk

The following command creates a FAT file system on a JAZ disk located on
a SPARC based system and overrides the sectors/track and tracks/cylinder
values obtained from the device's controller:

mkfs -F pcfs -o nsect=32,ntrack=64 /dev/rdsk/c0t3d0s2:c

ATTRIBUTES

NOTES

The default MS-DOS boot loader, which is installed by default if -o B is
not specified, requires specific MS-DOS system files to make the diskette
bootable. These MS-DOS files are not installed when you format a diskette
with mkfs for pcfs, which makes a diskette formatted this way not
bootable. Trying to boot from it on an x86 based system will result in
the following message:

Non-System disk or disk error
Replace and strike any key when ready

You must format a diskette with the DOS format command to install the
specific MS-DOS system files required by the default boot loader.

You can use lofiadm to create a file that appears to a mkfs command (for
example, mkfs_pcfs or mkfs_ufs) as a raw device. You can then use a mkfs
command to create a file system on that device. See lofiadm(8) for
examples of creating a UFS and a PC (FAT) file system on a device created
by lofiadm.

December 1, 2003 MKFS_PCFS(8)