ND floppy disks

Norsk Data floppy disks were originally only 8", but this later changed to 5 1/4". Newer systems would come with a dual 8" and 5 1/4" unit, and all ND software (e.g. SINTRAN-III and patch updates) were delivered on 5 1/4" floppies after the introduction of the smaller drives.

Both the 8" and in particular the 5 1/4" controllers could support a number of formats.

Formats supported by the 3027 floppy controller, 3106 and 3112 floppy/streamer controllers:
Additional formats only handled by the 3112 card:

Format identification numbers
The format identification number in the left column of the table was used to switch the floppy disk controller to the desired format before use, e.g. via the Sintran command DEVICE-FUNCTION.

Standard Norsk Data formats
The standard Norsk Data formats floppies were format 0b for 8" floppies and format 17b for 5 1/4" floppies. Only formats 0b and 17b could be used for a Sintran III file system or as a sequential-media volume for the BACKUP-SYSTEM application. The other formats could be used to support a foreign floppy disk format. Examples of the latter could be CP/M (8" single sided, single density, 128 bytes/sector, format 2b), or standard 80-track IBM PC 5 1/4" 1.25MB floppies (format 34b). None of the non-ND formats had built-in filesystem support in Sintran, so to read or write CP/M or IBM PC floppy disks the user would need to acquire or write specific software for it.

= Details of the default 8" and 5 1/4" formats =

8" format
The 8" Norsk Data format 0b was 512 bytes/sector, single sided/single density, 8 sectors per track, 77 tracks. The total capacity was 154 pages of 2048 bytes per page. Of this 148 pages could be allocated for files.

5 1/4" format
The 5 1/4" Norsk Data format 17b was 1024 bytes/sector, double sided/double density, 8 sectors per track, 77 tracks per side. The total capacity was 616 pages. Of this 612 pages could be allocated for files.

The floppy controller could use any of its supported formats on any media, 8" or 5 1/4", so it is also possible to have a format 17b 8" floppy disk. This became feasible when media with higher density became available.

= Reading a Norsk Data floppy on a Linux computer = A Linux computer equipped with a 5 1/4" floppy disk controller can read a Norsk Data floppy of format 17b. To do this the setfdprm tool is needed, which can be found in either the fdutils package or the util-linux package, depending on distribution. The version should be 5.2 or newer.

setfdprm /dev/fd0 sect=8 hd ssize=1024 cyl=77 dd if=/dev/fd0 bs=2048 count=616 of=file.image
 * Insert the floppy disk
 * Close the lever arm
 * Enter the following command (as user root):
 * The floppy can now be read with the following command:
 * Do not use the 'cat' command.
 * The setfdprm command must be repeated whenever a new floppy disk is inserted.
 * The floppy content will be found in the file.image file, or whatever output file defined by the of= parameter to the dd command.

If the above fails: Use this sequence instead of the single setfdprm command: fdrawcmd recalibrate 0 setfdprm /dev/fd0 sect=8 hd ssize=1024 cyl=77 Do this for every new floppy. If you forget the 'setfdprm' the drive may get into a read-error cyclic problem. If so, then insert the following command (once) before continuing with fdrawcmd, setfdprm: floppycontrol --resetnow 2 The above command, followed by the fdrawcmd recalibrate 0 command, will perform a full reset of the drive and 'setfdprm' should work afterwards. NB: Keep the floppy in the drive when executing these commands.

The format of the image data will normally be either a standard Sintran file system, or a backup volume. The Sintran file system is documented in.

= References =