User`s manual

Creating a Relative File
When a relative file is first to be used, the OPEN statement will create that
file;after that, that samefile willbe used.The replaceoption (withthe @)sign)
does not erase and re-create the file. The file can be expanded, read, and written
into.
FORMAT FORTHE OPENSTATEMENTTO CREATE RELATIVE FILE:
OPEN
file#, device#, channel#, "name,L," + CHR$(record length)
EXAMPLES OF OPEN STATEMENT CREATING RELATIVE FILES:
OPEN2, 8, 2, "FILE,L,"+CHR$(lOO)
OPEN F, 8, F, A$+ ",L,"+ CHR$(Q)
OPEN A, B,C, "TEST,L,"+ CHR$(33)
Record Length
Table 7.1 RELATIVE FILE FORMAT
34
DATA BLOCK
BYTE DEFINITION
0,1
Track and
sectorof next datablock.
2-256
254 bytes of data. Empty records contain FF (all binary ones)
in the first byte followed by 00 (binary all zeros) to the end of
the record. Partially filled records are padded with nulls (00).
SIDE SECTORBLOCK
BYTE DEFINITION
0,1
Trackand sector of next side sector block.
2
Side sector number. (0-5)
3
Record length.
4,5
Track and sector of first side sector (number 0)
6,7 Track and sector of second side sector (number 1)
8,9
Track and sector of third side sector (number 2)
10,11 Track and sector of fourth side sector (number 3)
12,13 Track and sector of fifth side sector (number 4)
14,15
Trackandsector of sicth side sector (number 5)
16-256
Trackand
sectorpointersto 120data blocks.