APPENDIX ELEVEN



3118           C2E            ....
     POKE with 0 to change only the first of matching filenames in
     case of duplication error in your directory (normally, Rename
     changes all files of the same name). POKE with 184 ($B8) to re-
     store. From the OS/A+ manual.

3460           D84            ....
     Deallocation bytes of the VTOC and directory; see the next few
     locations.

4226           1082           ....
     LSB of the current directory sector (first of eight reserved sec-
     tors). The directory is normally located in sectors 361-368. The
     default number here is 105 ($69).

4229           1085           ....
     MSB of current directory sector. To change the location of the
     directory, first copy the current sectors to the desired location
     (see 768 above), then POKE the new location of the first sector
     into the LSB/MSB bytes. That and the next seven sectors will be
     recognized as the new directory area. Finally, write the number
     for the new start sector (sector number/8 + 10) into 3460 ($D84).
     Leave BASIC and rewrite DOS onto a newly formatted disk. DOS
     disks with the original directory locations cannot read your
     directory.

     Disk Directories

     Format of a directory entry:

     Byte   Use
     0      Flag:
             $00 entry new (never used)
             $01 file opened for I/O
             $02 file created by DOS 2
             $20 file locked
             $40 file in use (normal)
             $80 file deleted
     1-2    Number of sectors in the file
     3-4    Starting sector number (LSB/MSB)
     5-12   Filename (space or $20 if blank)
     13Ä15  Extension

4264           10A8           ....
     LSB of the current VTOC (Volume Table Of Contents--only one
     sector reserved).