Formatting a disc on
a BBC Model B
OK. You've just bought a BeebMaster Disc Upgrade Kit, you've put it in the Beeb and put your lovely Beeb back together. All appears well and you've tried out a few discs of games and now you want to format your first disc.
You type *FORM80 0 and all you get is "Disk fault 18 at 00/00". Disaster!
Don't worry - this is quite normal! The reason is that the format utility was not built into the original 8271 DFS software. You will need a special formatting utility and if you can't find one, just type in the programme below and all your problems will be solved!
When RUN, this programme asks you for the drive to format and then formatting begins without any further warning so make sure you have the correct disc in the drive! At the end, there is the option to format another disc.
The routine here is an update from the version originally posted, with a number of improvements. Firstly, I've optimised the code, so at 63 lines, it's quite a bit shorter for typing in than the previous 96-line version. Secondly, I've corrected some previous errors in the format parameters to make them match the Acorn DFS specification. Thirdly, I've deleted the seek track immediately prior to each format track call, because the format track call does this anyway, so it's quite a bit quicker.
Fourthly, I've set it to write the disc map and catalogue twice, because sometimes the first time, the drive head hasn't quite caught up and so it fails. This appears to be a particular problem with modern 3½" drives. I could have used a seek track 0 command to ensure the head was in the right place before writing, but since I'd deleted the seek track code, it was easier to call the write map bit twice. Finally, there is a repeat loop to allow multiple discs to be formatted.
If it's too much to type (and remember that any line or section of line from "REM" onwards can be omitted to save time) then there is a download archive file here which contains a text file of the code as well as a tokenised BASIC version. It's up to you how you get it from here to your Beeb though!
Click here to go back