pcfs(7FS)

Name | Synopsis | Description | Examples | Files | See Also | Warnings | Notes | Bugs

Name

pcfs– DOS formatted file system

Synopsis

#include <sys/param.h>
#include <sys/mount.h>
#include <sys/fs/pc_fs.h>

int mount(const char *spec, const char *dir, int mflag, "pcfs",
     struct pcfs_args, struct *pc_argp, sizeof(struct pcfs_args));

Description

pcfs is a file system type that enables direct access to files on DOS 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 DOS formatted disk. You can also create and delete directories and list files in a directory.

pcfs supports FAT12 (floppies) and FAT16 and FAT32 file systems.

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 MS_DATA bit in mflag must be set. Mounting a pcfs file system requires a pointer to a structure containing mount flags and local timezone information, *pc_argp:

struct pcfs_args {
    int timezone;     /* seconds west of Greenwich */
    int daylight;     /* type of dst correction */
    int flags;
    };

The information required in the timezone and daylight members of this structure is described in ctime(3C). flags can contain the PCFS_MNT_FOLDCASE flag. Fold names read from the file system to lowercase.

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

You can use:

mount directory-name

if the following line is in your /etc/vfstab file:

device-special:logical_drive - 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 DOS 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 partition 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 (see vold(1M)) use:

mount -F pcfs /dev/diskette /pcfs/a

If Volume Management is running, run volcheck(1) to automatically 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 DOS short file name convention or the long file name convention introduced with Windows 95. The DOS 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 DOS short file name format, otherwise it creates 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 PCFS_MNT_FOLDCASE 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 DOS 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.

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 illegal 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

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

See Also

chgrp(1), chown(1), dos2unix(1), eject(1), fdformat(1), unix2dos(1), volcheck(1), mount(1M), mount_pcfs(1M), vold(1M), ctime(3C), vfstab(4), pcmem(7D)

Warnings

Do not physically eject a DOS 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 various 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 DOS use different character sets and have different requirements for the text file format. Use the dos2unix(1) and unix2dos(1) commands to convert files between them.

pcfs offers a convenient transportation vehicle for files between Sun workstations and PCs. Because the DOS disk format 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 exhibited by Windows 95 version 4.00.950.

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.

SunOS 5.10  Last Revised 10 Feb 2009

Name | Synopsis | Description | Examples | Files | See Also | Warnings | Notes | Bugs