ND floppy disks
ND Floppy Disk format
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 3106 and 3112 floppy and streamer controllers:
| Format | Identification | Sector size | Sides/Density |
|---|---|---|---|
| 0b | IBM SYS-32-II | 512 bytes/sector | SS/SD |
| 1b | IBM 3600 | 256 bytes/sector | SS/SD |
| 2b | IBM 3740 | 128 bytes/sector | SS/SD |
| 3b | - | ||
| 4b | Non IBM | 512 bytes/sector | DS/SD |
| 5b | Non IBM | 256 bytes/sector | DS/SD |
| 6b | Non IBM | 128 bytes/sector | DS/SD |
| 7b | - | ||
| 10b | Non IBM | 512 bytes/sector | SS/SD |
| 11b | IBM SYS-34 | 256 bytes/sector | SS/DD |
| 12b | - | ||
| 13b | Non IBM | 1024 bytes/sector | SS/DD |
| 14b | Non IBM | 512 bytes/sector | DS/DD |
| 15b | IBM SYS-34 | 256 bytes/sector | DS/DD |
| 16b | - | ||
| 17b | Non IBM | 1024 bytes/sector | DS/DD |
| Additional | formats only | handled by the | 3106 card: |
| 20b | - | ||
| 21b - | |||
| 22b | Basic 5 1/4" | 128 bytes/sector | SS/SD |
| 23b - 33b | - | ||
| 34b | IBM PC | ||
| 35b - 57b | - | ||
| 60b - 67b | User specified |
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. The other formats could be used as e.g. a volume for the backup-system application (i.e. as a sequential medium, like a tape drive), or 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. The total capacity was 616 pages. Of this 612 pages could be allocated for files.
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.[1]
- Insert the floppy disk
- Close the lever arm
- Enter the following command (as user root):
setfdprm /dev/fd0 sect=8 hd ssize=1024 cyl=77
- The floppy can now be read with the following command:
dd if=/dev/fd0 bs=2048 count=616 of=file.image
- 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.
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 Norsk Data Document ND–30.003 SINTRAN III System Supervisor .
References
Norsk Data Document ND–30.003 SINTRAN III System Supervisor
Norsk Data Document ND–11.015 FLOPPY DISK CONTROLLER - 3027
Norsk Data Document ND–11.021 FLOPPY AND STREAMER CONTROLLER 3106/3112