VDFS: OPENUP creates a new file if it doesn't already exist

[soruk42]

On DFS and ADFS, trying to OPENUP a file that doesn't already exist returns 0. However, on VDFS it's non-zero and a new file is created. This anomaly is even more surprising when running BASIC 1 and OPENIN (which became OPENUP in BASIC 2+) creates a file!

[hoglet67]

It might be worth running Tom Seddon's File System Test Suite on VDFS: https://github.com/tom-seddon/beeb-fstest

Dave

[SteveFosdick]

I have just run Tom's File System Test Suite. It needed hacking to detect VDFS and ADFS-like rather than DFS-like. Other than that it uses EXT#=, i.e. sets a file length from BASIC. This seems to be something introduced after BASIC 2 as that reports "Syntax Error". On a Master, it issues OSARGS with A=3 so I have implemented that, and fixed OSARGS A=1 so it extends the file if the pointer is moved beyond the end even if there no subsequent write,

It didn't detect this open for update issue, though. I have fixed that too, though.

[SteveFosdick]

https://github.com/stardot/b-em/commit/1431e7b0e527bc410288a6eedf5ce0cbbe7eac90

[soruk42]

Thank you - confirmed fixed. 👍