BBC BASIC for Windows: Disc drive check

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Disc drive check
Post by TheFamousCash on Mar 13^th, 2015, 9:38pm

I run a program which requires to delete a file if it is on disc.
Using "openup" to check if file is there produces error if drive empty as does SYS "FindFirstFile".
Please could someone advise how I check if there is a disc in the drive without generating an error?
Thanks.

Re: Disc drive check
Post by rtr2 on Mar 13^th, 2015, 10:21pm

on Mar 13^th, 2015, 9:38pm, TheFamousCash wrote:

Please could someone advise how I check if there is a disc in the drive without generating an error?

This doesn't answer your question, but I should point out that even if such a test exists it doesn't really help. There will always be a finite time window between you performing the test and attempting to delete the file, during which the disc could have been ejected. In that (admittedly unlikely) event you're back to square one.

Getting back to the problem, are you specifically referring to floppy discs? I don't think that SYS "DeleteFile" generally does generate an error if a removable disc (e.g. CD-ROM) is missing, but floppies are an exception.

Read this Raymond Chen blog post for some background:

http://blogs.msdn.com/b/oldnewthing/archive/2009/04/02/9528175.aspx

Richard.

Re: Disc drive check
Post by TheFamousCash on Mar 16^th, 2015, 02:21am

Richard,
Many thanks for your response.
Speaking of CDs containing programs in normal PC disc drive.
I found one of your functions which works perfectly:-
IFCD$="D"SYS "DeleteFile", src$+$fpt%, dst$+$fpt%, 0 TO res%
IFCD$="C"SYS "CopyFile", src$+$fpt%, dst$+$fpt%, 0 TO res%
However, if there is no disc in the drive, an error is generated showing "No disc is in drive".
I cannot find a method to circumvent this problem. (*CD, *DIR et cetera and attempting to see a file is on disc by using OPENUP, all generate the error.)
I thought I had settings which advised by email when a reply had been posted but just found your response in double-checking.
Thanks, Bob.

Re: Disc drive check
Post by sveinioslo on Mar 18^th, 2015, 12:16pm

Maybe this proc does the trick ?

Svein

Code:

 
      DEF PROCdeletefile(file$)
      ON ERROR LOCAL : ENDPROC
      OSCLI "DEL "+file$
      ENDPROC

Re: Disc drive check
Post by rtr2 on Mar 18^th, 2015, 1:03pm

on Mar 18^th, 2015, 12:16pm, sveinioslo wrote:

Maybe this proc does the trick ?

Or, more straightforwardly (and no need for a PROC):

Code:

      SYS "DeleteFile", file$

But I already suggested that to the OP, and he said he tried it, so probably the error message he is referring to is a popup window like the one you get with a missing floppy.

Richard.

Re: Disc drive check
Post by sveinioslo on Mar 18^th, 2015, 9:55pm

I was hoping that the "No disc is in drive" error was trappable.
Can't test it at my current location.

Svein

Re: Disc drive check
Post by TheFamousCash on Mar 19^th, 2015, 12:21pm

Many thanks for assistance. I have found solution. Cycling through to discover which LT$ is actual disc drive using below PROC and checking to see if file$ present. If CDFLAG%=1 then simple OSCLI "DEL """+file$+"""" completes.

DEFPROCCHECKDISK(LT$)
ON ERROR LOCAL:ENDPROC
OSCLI "CD """+LT$+""""
LOCAL dir%, sh%, res%
DIM dir% LOCAL 317
SYS "FindFirstFile", "*", dir% TO sh%
IFsh%<>-1P%=OPENUPfile$:IFP>0CDFLAG=1:CLOSE#P%
ENDPROC