ref: f8ddcb23b9dd969875dd4e961591700c79b7d5f7
dir: /sys/man/4/dossrv/
.TH DOSSRV 4 .SH NAME dossrv, 9660srv, dosmnt, eject \- DOS and ISO9660 file systems .SH SYNOPSIS .B dossrv [ .B -rsv ] [ .B -f .I file ] [ .I service ] .PP .B 9660srv [ .B -9Jsv ] [ .B -c .I clusters ] [ .B -f .I file ] [ .I service ] .PP .B dosmnt .I n .I mtpt .PP .B eject [ .I n ] .SH DESCRIPTION .I Dossrv is a file server that interprets DOS file systems. A single instance of .I dossrv can provide access to multiple DOS disks simultaneously. .PP .I Dossrv posts a file descriptor named .I service (default .BR dos ) in the .B /srv directory. To access the DOS file system on a device, use .B mount with the .I spec argument (see .IR bind (1)) the name of the file holding raw DOS file system, typically the disk. If .I spec is undefined in the .BR mount , .I dossrv will use .I file as the default name for the device holding the DOS system. .PP Normally .I dossrv creates a pipe to act as the communications channel between itself and its clients. The .B -s flag instructs .I dossrv to use its standard input and output instead. The kernels use this option if they are booting from a DOS disk. This flag also prevents the creation of an explicit service file in .BR /srv . .PP The .B -v flag causes verbose output for debugging, while the .B -r flag makes the file system read-only. .PP The file attribute flags used by the DOS file system do not map directly to those used by Plan 9. Since there is no concept of user or group, permission changes via .B wstat (see .IR stat (2)) will fail unless the same (read, write, execute) permissions are specified for user, group, and other. For example, removing write permission in Plan 9 corresponds to setting the read-only attribute in the DOS file system. Most of the other DOS attributes are not accessible. .PP Setting the exclusive use flag (DMEXCL) in Plan 9 corresponds to setting the system use attribute in the DOS file system. Such files are not actually restricted to exclusive use, but do merit special treatment that helps in the creation of boot disks: when .I dossrv allocates a new block for such a file (caused, say, by a write that fills the file's last allocated block), it succeeds only if it can arrange for the file to be stored contiguously on disk. .PP Since other operating systems do not guarantee that system files are laid out contiguously, the DMAPPEND mode bit is set in file stat information only when the file is currently contiguous. Attempts to set the DMAPPEND mode bit explicitly will cause .I dossrv to try to make the file contiguous, succeeding only if this is possible. .PP .I 9660srv is similar to .I dossrv in specification, except that it interprets ISO9660 CD-ROM file systems instead of DOS file systems. Some CDs contain multiple directory trees describing the same set of files. .IR 9660srv 's first choice in such a case is a standard ISO9660 tree with Plan 9 system use fields; the second choice is a Microsoft ``Joliet'' tree, which allows long file names and Unicode characters; the third choice is a standard ISO9660 or High Sierra tree. The .B -9 flag causes .I 9660srv to ignore the Plan 9 system use fields, while the .B -J flag causes it to ignore the Joliet tree. The .B -c option sets the size of the RAM cache to .I clusters clusters of 128KB. The default .I clusters is 16, but a value of 5600 will cache an entire CD incrementally. .PP If the floppy drive has an ejection motor, .I eject will spit out the floppy from drive .IR n , default 0. .SH SOURCE .B /sys/src/cmd/dossrv .br .B /sys/src/cmd/9660srv .br .B /rc/bin/eject .br .B /rc/bin/dosmnt .SH BUGS The overloading of the semantics of the DMEXCL and DMAPPEND bits can be confusing.