The Programmer's Guide to TRSDOS Version 6 - Tim Mann's Home ...

0-14 FILENAME/EXT:D - left justified and buffered with spaces
15 Protection level (0-6)
16 End of File (EOF) offset byte
17 Logical Record Length (0 implies 256)
18-19 Ending Record Number (ERN) of the file
20-21 Space allocated for the file (in K)
Free Space
The SVC linkage to accomplish a retrieval of free space is as follows:
Registers Affected: AF.
Entry:
C 255; Obtain free space information.
B Should contain the logical drive (0-7) for the disk.
HL A pointer to your buffer which will be passed the data.
Exit:
A Returns an error code if the operation encountered an error.
Z Set if the SVC was successful.
The total space allocated to files (in K) is returned in the first two bytes of
the buffer while the total space left available (in K) is stored in the third and
fourth bytes of the buffer.
7.6.66 @RDHDR SVC-48
This SVC passes a function 8 to a disk driver. It is commonly used for reading sector
header information from the next encountered sector ID field of a floppy disk . See
chapter 4 for additional information.
Registers Affected: AF [Note: DOS saves BC, IY; drivers should save any other
registers they use].
Entry:
C Logical drive number (0-7).
HL A pointer to the buffer which will receive the data transfer.
Exit:
A Contains an error return code, if any.
Z Set if the operation was successful.
7.6.67 @RDSEC SVC-49
This SVC passes a function 9 to a disk driver. This is used to transfer a sector of data
from the disk drive to your buffer. See chapter 4 for additional information.
Registers Affected: AF [Note: DOS saves BC, IY; drivers should save any other
registers they use].
Entry:
HL A pointer to the buffer to receive the sector of data.
D Contains the logical cylinder number to read (0-255).
E Contains the logical sector number to read (0-255).
C Contains the the logical drive number.
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