Commodore RF512C - Disk Format

APPENDIX B
DISK FORMAT
37
T hi s disk hierarchy
DIRECTORY-HEADER
FILE VECTOR TABLE-PROGRAM FILE
SEQUENTIAL FILE
USER FILE
RELATIVE FILE - SIDE SECTOR
DATA SECTOR
DIRECTORY HEADER (locate at track 18 se ctor 0)
BYTE
CONTENTS
0
Next tra
ck
1 Next sector
2
Usually 65
3
d x128
4t
nool fr ee sector on track t
4t+ 1
BAM of sector 0 to 7 of tr ack t
4t + 2
BAM of sector 8 to 16 of track t
4t+ 3
BAM of sector 17 + 23 of track t
144 to 143+ L
disk na
me with leng th L
144
+Llo 159 160 ill <16
162 fir st ID
163
second ID
164
Usually 160
165
Usually 50
166
Usually 65
167 to 170
Usually fill
ed wi th 160
171 to 179
Usually fill
ed with 0
180 to 191
st ri ng " BLOCK FREE :'
192 to 220
Us ua ll y fil l ed with 0
I' + 1 85
no of free sector on tract I'
Where d is the dou ble side fl ag (128 for doub le side; 0 for
single side).
t
is the t rack no . fr om 1 to 35 .
I' is the track no. from 36 to 70.