Hi,

Is there a simple test I can use in BASIC to determine whether a DFS is present without using PAGE?

Sam.

Actually, it doesn't look like I need this anyway. Though it be handy to know anyway if anyone has any ideas?

Sam.

I woke up with the obvious idea of using ON ERROR. Must remember to sleep on it next time!

Sam.

hmm ... actually that doesn't quite do what I want. That'll tell me if a DFS is present but not whether it's the currently selected filing system which I think is what I'm really after.

Is there a memory location I can query which will tell me?

Sam.

OSARGS 0,0 will do that...


FS% now contains the current file system.

See here for a list of values http://beebwiki.jonripley.com/OSARGS

blast typed too slow.

Anyway 'A' will then return the current filing system, figured you might be using machine code.

Thanks, Pauls!

PaulDv's code is exactly what I was looking for. It's going in a BASIC menu, so that fits the bill perfectly.

Sam.

You shouldn't unnessessarily restrict your program's functionality when it's running on DFS unless it's absolutely neccessary. Especially, don't make your program jump through complicated hoops for DFS when non-specific filing systems calls do the job just as well. I've seen abominations of code that effectively do:
IF (NOT DFS) THEN use API to read directory
ELSE VDU 21, *CAT, VDU 6, peek memory

when the correct code is just... use API to read directory.

Also, as some filing systems that respond with fs=4 have more functionality than Acorn DFS (eg HDFS, WatfordDFS), and some filing systems that respond with fs<>4 actually have the same functionality as DFS (eg RetroRAMFS), in some cases a better test is: dfs%=FNfile("$",5)<>2. See the Wiki article.

(PS: Is there any way to get inline code in the above paragraph, not having appear as a seperate paragraph?)