10 ! PROGRAM TO CALCULATE BITMAP BLOCK, WORD AND BIT NUMBER
11 ! CORRESPONDING TO AN ENTERED FILE ID NUMBER
20 PRINT 
30 PRINT "DISK MUST BE MOUNTED '/UNL'"
40 PRINT "ZAP>DDN:[0,0]INDEXF.SYS/AB"
60 PRINT "3:NNNNN\VVV"
65 PRINT "CLEAR BIT TO SHOW HEADER AVAILABLE, SET TO SHOW USED"
70 PRINT "-BBB"
80 PRINT "-X"
90 PRINT 
100 INPUT "FILE ID NUMBER (OCTAL) ";FI$
110 FI=OCT(FI$)
120 FI=FI-1
130 HI=INT(FI/8) : LO=FI-8*HI
140 PRINT "BYTE NUMBER = ";OCT$(HI)
145 MA=2^LO
150 PRINT " BIT MASK   = ";OCT$(MA)
160 GOTO 100