File Systems pcfs(7FS)
NAME
pcfs - FAT formatted file system
SYNOPSIS
#include
#include
#include
int mount(const char *spec,
const char * dir, int mflag,
"pcfs", NUL, 0, char *optptr,
int optlen);
DESCRIPTION
pcfs is a file system type that enables direct access to
files on FAT formatted disks from within the SunOS operating
system.
Once mounted, pcfs provides standard SunOS file operations
and semantics. Using pcfs, you can create, delete, read, and
write files on a FAT formatted disk. You can also create and
delete directories and list files in a directory.
pcfs supports FAT12 (floppies) and FAT16 and FAT32 file sys-
tems.
pcfs file systems can be force umounted using the -f argu-
ment to umount(1M).
The pcfs file system contained on the block special file
identified by spec is mounted on the directory identified by
dir. spec and dir are pointers to pathnames. mflag specifies
the mount options. The MSDATA bit in mflag must be set.
Mount options can be passed to pcfs using the optptr and
optlen arguments. See mountpcfs(1M) for a list of mount
options supported by pcfs.
Because FAT formatted media can record file timestamps
between January 1st 1980 and December 31st 2127, it's not
possible to fully represent UNIX timet in pcfs for 32 bit
or 64 bit programs. In particular, if post-2038 timestamps
are present on a FAT formatted medium and pcfs returns
these, 32bit applications may unexpectedly fail with EOVER-
FLOW errors. To prevent this, the default behaviour of pcfs
has been modified to clamp post-2038 timestamps to the
latest possible value for a 32bit timet, which is January
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File Systems pcfs(7FS)
19th 2038, 03:14:06 UTC when setting and retrieving file
timestamps. You can override this behavior using the
noclamptime mount option, as described in mountpcfs(1M).
Timestamps on FAT formatted media are recorded in local
time. If the recording and receiving systems use different
timezones, the representation of timestamps shown on the two
systems for the same medium might vary. To correct this,
pcfs provides a timezone mount option to force interpre-
tation of timestamps as read from a FAT formatted medium in
a given timezone (that of the recorder). By default, the
local timezone of the receiver is used. See mountpcfs(1M)
for details.
The root directory of a FAT formatted medium has no times-
tamps and pcfs returns the time when the mount was done as
timestamp for the root of the filesystem.
The FAT filesystem doesn't support multiple links. As a
result, the link count for all files and directories in pcfs
is hard-coded as "1."
Mounting File Systems
Use the following command to mount pcfs from diskette:
mount -F pcfs device-special directory-name
You can use:
mount directory-name
if the following line is in your /etc/vfstab file:
device-special - directory-namepcfs - no rw
Use the following command to mount pcfs from non-diskette
media:
mount -F pcfs device-special:logical-drive directory-name
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File Systems pcfs(7FS)
You can use:
mount directory-name
if the following line is in your /etc/vfstab file:
device-special:logicaldrive - directory-name pcfs - no rw
device-special specifies the special block device file for
the diskette (/dev/disketteN) or the entire hard disk
(/dev/dsk/cNtNdNp0 for a SCSI disk, and /dev/dsk/cNdNp0 for
IDE disks) or the PCMCIA pseudo-floppy memory card
(/dev/dsk/cNtNdNsN).
logical-drive specifies either the DOS logical drive letter
(c through z) or a drive number (1 through 24). Drive letter
c is equivalent to drive number 1 and represents the Primary
DOS partition on the disk; drive letters d through z are
equivalent to drive numbers 2 through 24, and represent DOS
drives within the Extended FAT partition. Note that device-
special and logical-drive must be separated by a colon.
directory-name specifies the location where the file system
is mounted.
For example, to mount the Primary DOS partition from a SCSI
hard disk, use:
mount -F pcfs /dev/dsk/cNtNdNp0:c /pcfs/c
To mount the first logical drive in the Extended DOS parti-
tion from an IDE hard disk, use:
mount -F pcfs /dev/dsk/cNdNp0:d /pcfs/d
To mount a DOS diskette in the first floppy drive when
volume management is not running use:
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File Systems pcfs(7FS)
mount -F pcfs /dev/diskette /pcfs/a
If Volume Management is running, run volcheck(1) to automat-
ically mount the floppy and some removable disks.
To mount a PCMCIA pseudo-floppy memory card, with Volume
Management not running (or not managing the PCMCIA media),
use:
mount -F pcfs /dev/dsk/cNtNdNsN /pcfs
Conventions
Files and directories created through pcfs must comply with
either the FAT short file name convention or the long file
name convention introduced with Windows 95. The FAT short
file name convention is of the form filename[.ext], where
filename generally consists of from one to eight upper-case
characters, while the optional ext consists of from one to
three upper-case characters.
The long file name convention is much closer to Solaris file
names. A long file name can consist of any characters valid
in a short file name, lowercase letters, non-leading spaces,
the characters ],;=[], any number of periods, and can be up
to 255 characters long. Long file names have an associated
short file name for systems that do not support long file
names (including earlier releases of Solaris). The short
file name is not visible if the system recognizes long file
names. pcfs generates a unique short name automatically when
creating a long file name.
Given a long file name such as This is a really long
filename.TXT, the short file name will generally be of the
form THISIS~N.TXT, where N is a number. The long file name
will probably get the short name THISIS~1.TXT, or
THISIS~2.TXT if THISIS~1.TXT already exits (or THISIS~3.TXT
if both exist, and so forth). If you use pcfs file systems
on systems that do not support long file names, you may want
to continue following the short file name conventions. See
EXAMPLES.
When creating a file name, pcfs creates a short file name if
it fits the FAT short file name format, otherwise it creates
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File Systems pcfs(7FS)
a long file name. This is because long file names take more
directory space. Because the root directory of a pcfs file
system is fixed size, long file names in the root directory
should be avoided if possible.
When displaying file names, pcfs shows them exactly as they
are on the media. This means that short names are displayed
as uppercase and long file names retain their case. Earlier
versions of pcfs folded all names to lowercase, which can be
forced with the PCFSMNTFOLDCASE mount option. All file
name searches within pcfs, however, are treated as if they
were uppercase, so readme.txt and ReAdMe.TxT refer to the
same file.
To format a diskette or a PCMCIA pseudo-floppy memory card
in FAT format in the SunOS system, use either the fdformat
-d or the DOS FORMAT command.
Boot Partitions
On x86 systems, hard drives may contain an fdisk partition
reserved for the Solaris boot utilities. These partitions
are special instances of pcfs. You can mount an x86 boot
partition with the command:
mount -F pcfs device-special:boot directory-name
or you can use:
mount directory-name
if the following line is in your /etc/vfstab file:
device-special:boot - directory-name pcfs - no rw
device-special specifies the special block device file for
the entire hard disk (/dev/dsk/cNtNdNp0)
directory-name specifies the location where the file system
is mounted.
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File Systems pcfs(7FS)
All files on a boot partition are owned by super-user. Only
the super-user may create, delete, or modify files on a boot
partition.
EXAMPLES
Example 1 Sample Displays of File Names
If you copy a file financial.data from a UNIX file system to
pcfs, it displays as financial.data in pcfs, but may show up
as FINANC~1.DAT in systems that do not support long file
names.
The following are legal long file names. They are also ille-
gal short file names:
test.sh.orig
data]
.login
Other systems that do not support long file names may see:
TESTSH~1.ORI
DATA~1
LOGIN~1
The short file name is generated from the initial characters
of the long file name, so differentiate names in the first
few characters. For example, these names:
WorkReport.January.Data
WorkReport.February.Data
WorkReport.March.Data
result in these short names, which are not distinguishable:
WORKRE~1.DAT
WORKRE~2.DAT
WORKRE~13.DAT
These names, however:
January.WorkReport.Data
February.WorkReport.Data
March.WorkReport.Data
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File Systems pcfs(7FS)
result in the more descriptive short names:
JANUAR~1.DAT
FEBRUA~1.DAT
MARCHW~1.DAT
FILES
/usr/lib/fs/pcfs/mount pcfs mount command
/usr/kernel/fs/pcfs 32-bit kernel module
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables for the current locale setting: LANG, LCAL,
LCTYPE, and LCOLATE.
SEE ALSO
chgrp(1), chown(1), dos2unix(1), eject(1), fdformat(1),
unix2dos(1), volcheck(1), mount(1M), mountpcfs(1M),
umount(1M), ctime(3C), vfstab(4), environ(5), pcmem(7D)
WARNINGS
Do not physically eject a FAT floppy while the device is
mounted as pcfs. If Volume Management is managing a device,
use the eject(1) command before physically removing media.
When mounting pcfs on a hard disk, make sure the first block
on that device contains a valid fdisk partition table.
Because pcfs has no provision for handling owner-IDs or
group-IDs on files, chown(1) or chgrp(1) may generate vari-
ous errors. This is a limitation of pcfs, but it should not
cause problems other than error messages.
NOTES
Only the following characters are allowed in pcfs short file
names and extensions:
0-9
A-Z
$#&@!%()-{}<>`^~'
SunOS and FAT use different character sets and have dif-
ferent requirements for the text file format. Use the
dos2unix(1) and unix2dos(1) commands to convert files
between them.
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File Systems pcfs(7FS)
pcfs offers a convenient transportation vehicle for files
between Sun workstations and PCs. Because the FAT disk for-
mat was designed for use under DOS, it does not operate
efficiently under the SunOS system and should not be used as
the format for a regular local storage. Instead, use ufs for
local storage within the SunOS system.
Although long file names can contain spaces (just as in UNIX
file names), some utilities may be confused by them.
This implementation of pcfs conforms to the behavior exhi-
bited by Windows 95 version 4.00.950.
When pcfs encounters long file names with non-ASCI charac-
ters, it converts such long file names in Unicode scalar
values into UTF-8 encoded filenames so that they are legible
and usable with any of Solaris UTF-8 locales. In the same
context, when new file names with non-ASCI characters are
created, pcfs expects that such file names are in UTF-8.
This feature increases the interoperability of pcfs on
Solaris with other operating systems.
BUGS
pcfs should handle the disk change condition in the same way
that DOS does, so you do not need to unmount the file system
to change floppies.
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