FLOPPY(3) Library Functions Manual FLOPPY(3)NAME
floppy - floppy disk interface
SYNOPSIS
bind -a #f /dev
/dev/fd0disk
/dev/fd0ctl
/dev/fd1disk
/dev/fd1ctl
/dev/fd2disk
/dev/fd2ctl
/dev/fd3disk
/dev/fd3ctl
DESCRIPTION
The floppy disk interface serves a one-level directory giving access to up to four floppy disk drives. Each drive is represented by a data
and control file. There are no partitions.
Messages accepted by the ctl file include:
eject Eject the floppy, if possible.
reset Reset the drive.
format type
(Not on the Nextstation) Format the floppy. The type sets the density and type of disk to be formatted; see format in prep(8).
A read of the ctl file returns a string describing the form factor of the disk, one of 31/2DD, 31/2HD, 51/4DD, or 51/4HD.
SOURCE
/sys/src/9/port/devfloppy.c
FLOPPY(3)
Check Out this Related Man Page
PREP(8) System Manager's Manual PREP(8)NAME
prep, format - prepare hard and floppy diskettes
SYNOPSIS
disk/prep [ -ra ] special [ type ]
disk/format [ -t type ] [ -f ] [ -d ] [ -b bfile ] [ -c csize ] [ -l label ] drive [ files ... ]
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 Plan 9 the parti-
tion table is a list of triples: name, starting sector, and ending sector. The kernel fabricates the first two partitions, disk and parti-
tion; the disk partition records the starting and ending sectors for the whole disk, and the partition partition, typically the last sector
on the disk, holds the partition table itself.
Special is the maximal prefix of names of the logical units on the disk, for example #w/hd0. Prep reads and prints the associated parti-
tion table and then enters a simple interactive mode to control editing the table.
The options are:
-r (read only) prohibits writing the table on disk.
-a automatically create default partitions if no partition table already exists. These include partitions for DOS, a boot kernel, an
NVRAM substitute, a kfs(4) file system, and, if room remains, a swap partition.
Format prepares for use the floppy diskette in the disk file named drive, for example /dev/fd0disk. The options are:
-f Do not physically format the disc. Used to install an MS-DOS filesystem on a previously formatted disc. With this option, drive can
be a plain file.
-t specify a density and type of disk to be prepared. The possible types are:
31/2DD 31/2" double density, 737280 bytes
31/2HD 31/2" high density, 1474560 bytes
51/4DD 51/4" double density, 368640 bytes
51/4HD 51/4" high density, 1146880 bytes
The default is the highest possible on the device, unless -f is used, in which case the default is 31/2HD.
-d add MS-DOS parameter block, file access table (FAT), and root directory to the start of the floppy.
The remaining options have effect only when -d is specified:
-b use the contents of bfile as the bootstrap block installed in sector 0.
-c use a DOS cluster size of csize sectors when creating the DOS FAT.
-l add a label when creating the DOS parameter block.
Again under -d, any files listed are added, in order, to the root directory of the MS-DOS filesytem. The files are contiguously allocated
and created with the READONLY attribute set.
The file /sys/src/boot/pc/bb is an example of a suitable bfile to make the disk a boot disk. It gets loaded by the BIOS at 0x7C00, reads
the root directory into address 0x7E00, and looks at the first root directory entry. If that file is called B.COM, it uses single sector
reads to load the file into address 0x10000 and then jumps to the loaded file image.
EXAMPLE
Create a Plan 9 boot floppy on a previously formatted diskette:
disk/format -f -b bb -d /dev/fd0disk /386/b.com
SOURCE
/sys/src/cmd/disk/prep.c
/sys/src/cmd/disk/format.c
/sys/src/boot/pc/bb.s
SEE ALSO floppy(3), wren(3), b.com(8)PREP(8)