Sflp(HW)

Sflp, LS-120, LS-240, floptical -- generic floppy device interface

Description

The Sflp device driver is a generic peripheral driver for any SCSI, ATAPI, or USB removable storage device that is not recognized by the fd(HW) driver as a standard floppy drive. Such devices include:

SuperDisk 240 (LS-240) drives
SuperDisk 120 (LS-120) drives
floppy drives
floptical drives

Sflp devices provide read/write access to 3.5" media, including:

240MB SuperDisk 240 (LS-240)
120MB SuperDisk 120 (LS-120, UHD)
21MB floppy disks (VHD)*
1.44MB floppy disks (HD)
720KB floppy disks (DD)

*: Very high density disks (VHD or floptical disks) are special, preformatted, combined optical/magnetic media; they are hard-formatted by optical means, allowing magnetic data to be read and written at a much higher density than on normal disks. VHD disks can be only read by floptical drives, which are SCSI-1 CCS-compliant devices that can be accessed using standard SCSI commands via a host adapter.

The following table lists the floppy media types that can be read by Sflp devices.

Media

Devices LS-240 LS-120 VHD HD DD

SuperDisk 240 X X X X

SuperDisk 120 X X X X

floptical X X X

floppy X X

	Media
Devices	LS-240	LS-120	VHD	HD	DD
SuperDisk 240	X	X		X	X
SuperDisk 120	X	X		X	X
floptical			X	X	X
floppy				X	X

By default, Sflp units are enumerated last in the list of floppy devices. For example, if there is a standard floppy drive and an LS-120 drive on a system, the LS-120 will be /dev/fd1 and the standard floppy will be /dev/fd0. (This ordering can be remapped by editing the floppy driver's /etc/conf/pack.d/fd/space.c file.)

The standard floppy driver, fd(HW), is aware of Sflp devices, and requests sent to /dev/fd0 will be passed to the corresponding Sflp device if fd0 is not a standard floppy drive.

The Sflp device driver supports all ioctl(S) calls that are recognized by the floppy disk driver. This means, for example, that you can format floppy disks in an LS-120 drive using format(C). Also, as with floppy disks, you can use:

archiving and conversion commands: tar(C), cpio(C), dd(C).
filesystem administration commands: divvy(ADM), fdisk(ADM), fsck(ADM), fstyp(ADM), mount(ADM).

NOTE: By default, Sflp allows you to format LS-120 or floppy devices. It can also format floptical devices by setting a flag in the /etc/conf/pack.d/Sflp/space.c file, but while set it cannot format LS-120 or USB devices.

Formatting LS-240 media is not yet supported. You cannot format media on USB removable storage devices.

The mkdev ls120 (and identical mkdev flopti) script is used to install or remove these removable storage devices.

Minor device numbering

The minor device bit representation scheme for floppy drives is shown in the table below. Using this table, you can construct the minor device number of any allowable floptical configuration.

Bits

9 8 7 6 5 4 3 2 1 0 Description

- - - - - - - 0 0 1 1.44MB (HD)

- - - - - - - 0 1 0 autodetect format *

- - - - - - - 0 0 0 720KB (DD)

- - - - - - - 1 0 0 21MB (VHD)

- - - 0 - 0 0 - - - Reserved +

- - - - 0 - - - - - Set to zero

X X X - - - - - - - Unit # (0-6) ++

Bits
9	8	7	6	5	4	3	2	1	0	Description
-	-	-	-	-	-	-	0	0	1	1.44MB (HD)
-	-	-	-	-	-	-	0	1	0	autodetect format *
-	-	-	-	-	-	-	0	0	0	720KB (DD)
-	-	-	-	-	-	-	1	0	0	21MB (VHD)
-	-	-	0	-	0	0	-	-	-	Reserved +
-	-	-	-	0	-	-	-	-	-	Set to zero
X	X	X	-	-	-	-	-	-	-	Unit # (0-6) ++

*: Bits 0-2 have no provision for LS-120 media, because UHD media can be correctly detected when the autodetect bit is turned on.
+: Reserved for future support of floppy devices.
++: Bits 8 and 9 are only used if extended minor numbering is used to support several floptical drives.

As an example, the minor device number for the block special device file for a second floptical drive using HD disks is 129 corresponding to a bit pattern of ``10000001''.

Device file naming

Six special device files are generated by the mkdev ls120 script; one block and one raw device for each of the three supported formats. The following table shows the device file naming convention (the drive number is shown by n):

Disk format Block device Character (raw) device

autodetect /dev/dsk/fpn0 /dev/rdsk/fpn0

1.44MB (HD) /dev/dsk/fpn0h /dev/rdsk/fpn0h

720KB (DD) /dev/dsk/fpn0d /dev/rdsk/fpn0d

Disk format	Block device	Character (raw) device
autodetect	/dev/dsk/fpn0	/dev/rdsk/fpn0
1.44MB (HD)	/dev/dsk/fpn0h	/dev/rdsk/fpn0h
720KB (DD)	/dev/dsk/fpn0d	/dev/rdsk/fpn0d

Note that floptical drives are numbered 0 for the first installed drive to 6. For example, the block special device file for a second floptical drive using HD disks is /dev/dsk/fp10h.

Limitations

Use of 2.88MB floppy disks in floptical drives is not supported.

Formatting VHD 21MB disks in a floptical drive can take up to 30 minutes.

It is not possible to create a boot floptical disk or to boot from a disk in a floptical drive.

As is the case for floppy disks, you can make a filesystem on a floptical disk using mkfs(ADM), and subsequently mount this using mount(ADM). However, it is not possible to use a floptical disk as a removable hard disk; for example, you cannot partition a floptical disk using fdisk(ADM).

You cannot format media on USB removable storage devices.

Files