Calculating blocks free

[xlar54]

Hey guys,

I need a quick basic prog that will do the BAM calculation of blocks free on a 1541 disk. I know that the 4th byte of the BAM (T18, S0), added up is supposed to give this value, but Im way off for some reason. On the test/demo disk for the 1541, i keep coming up with 492 blocks free, instead of the 558 that is presented by the Commodore 64/128.

If you can help, thanks in advance.

[pearsoe]

10 a=0:c=1
20 open 15,8,15
30 print#15,"I0"
40 input#15,EN$,EM$,ET$,ES$
50 if EN$<>"00" goto 170
60 open2,8,2,"#"
70 print#15,"U1;2;0;18;0
80 input#15,EN$,EM$,ET$,ES$
90 if EN$<>"00" goto 170
95 get#2,B$
100 for i=1to140
110 get#2,b$
120 if b$="" then b$=chr$(0)
130 if c=4 then a=a+asc(b$)
140 if i=72 then a=a-asc(b$)
150 c=c+1:if c=5 then c=1
160 next i
170 close2:close15
180 print a

quick and dirty but it does the job. you have to subtract track 18 from the total of all tracks, this is done in line 140.

[xlar54]

Dude, you rock.  Thank you very much!

Edit - running it, I get DOS error 70 ( NO CHANNEL AVAILABLE ).  Im running it under VICE, so maybe that has something to do with it.  If you have any edits, let me know, but thanks again

[pearsoe]

Originally I tested it on a C-128 in C-64 mode with a 1541-II drive. Just tried it on WinVice 1.22 with a 1541 test/demo D64 attached to drive and it worked perfectly. I used the 1541 test /demo D64 from here:

http://www.zimmers.net/anonftp/pub/cbm/demodisks/drives/index.html

[xlar54]

Heh... suffice to say the program works... apparently my eyesight doesnt (user typing error)... Thanks again!