User`s guide
1541 BLOCK DISTRIBUTION BY TRACK
Track
number
Range
of
Sectors
Total #
of
Sectors
I to
17
18
to 24
25
to 30
31to35
BYTE
CONTENTS
0,1
18,01
2
65
3
0
4-143
0 to 20
0
to
18
0 to
17
0 to
16
1541
BAM FORMAT
Track
18, Sector 0.
DEFINITION
Track and sector
of
first directory block.
21
19
18
17
ASCII character A indicating 1541/4040 format.
Null
flag
for future DOS use.
Bit map
of
the available blocks
in
tracks
1-35
.
I - available block
0 = block not available (each bit represents one block)
BYTE
144-159
160-161
162-163
164
165-166
167-170
170-255
1541 DIRECTORY HEADER
Track
18, Sector 0.
CONTENTS
DEFINITION
Diskette name padded with shifted spaces.
160
Shifted spaces.
Diskette ID.
160
Shifted space
50,65
ASCII representation
of
2A, which are, respectively,
the
DOS version (2) and format type (1541/4040).
160
Shifted
spaces.
0
Nulls ($00), not used.
88
,
,_
PROGRAM
FILE
FORMAT
.
BYTE
DEFINITION
FIRST SECTOR
0,1
Track and sector
of
next block
in
program
file
.
2,3 Load address
of
the program
4-255
Next 252 bytes
of
program information stored
as
in
computer
memory (with key words tokenized).
REMAINING FULL
SECTORS
0,1
Track and sector
of
next block
in
program
file
.
2-255
Next 254 bytes
of
program info stored as
in
computer memory
(with
key words tokenized).
FINAL
SECTOR
0,1
Null ($00), followed
by
number
of
valid data bytes
in
sector.
2-??? Last bytes
of
the program information, stored
as
in
computer
memory (with key words tokenized). The end of a Basic
file
is
marked
by
3 zero bytes
in
a row . Any remaining bytes
in
the
sector are garbage, and may be ignored.
SEQUENTIAL
FILE
FORMAT
BYTE
DEFINITION
ALL BUT FINAL SECTOR
0-1
Track and sector
of
next sequential data block .
2-255 254 bytes
of
data.
FINAL
SECTOR
0,1
Null ($00), followed by number of valid data bytes
in
sector.
2-???
Last bytes
of
data. Any remaining bytes are garbage and may
be
ignored.
89
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