Disc System User Guide (1982).

A=0 Save a section of memory as a named file. The files catalogue
information is also written
A=1 Write the catalogue information for the named file
A=2 Write the load address (only) for the named file
A=3 Write the execution address (only) for the named file
A=4 Write the attributes (only) for the named file
A=5 Read the named files catalogue information. Place the file type in A.
A=6 Delete the named file
A= &FF Load the named file
When loading a file the byte at XY+6 (the LSB of the execution address),
determines where the, file will be loaded in memory. If it is zero then the file
will be loaded to the address given in the control block. If non-zero then the
file will be loaded to the address stored with the file when it was created.
The file attributes are stored in four bytes. The least significant 8 bits
have the following meanings:
Bit Meaning
0 not readable by you
1 not writable by you
2 not executable by you
3 not deletable by you
4 not readable by others
5 not writable by others
6 not executable by others
7 not deletable by others
File names are as follows:
0 nothing found
1 file found
2 directory found
A BRK will occur in the event of an error and this can be trapped if
required.
On exit X and Y are preserved, C, N, V and Z are undefined and D=0. The
interrupt state is preserved but interrupts may be enabled during the
operation.
Read/write one byte
OSBGET call address &OFFD7 to get a byte
OSBPUT call address &OFFD4 to put a byte
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