Tandy 1000 SL Technical Reference Manual page 552

BIOS Services
Disk I/O Support for Diskette Only
System Configuration
Software Interrupt
13 hex (19 dec)
Function Summary
AH
=
0:
AH
=
1:
AH
=
2:
AH
=
3:
AH
=
4:
AH
=
5:
AH
=
08H:
AH
=
15H:
AH
=
16H:
Reset diskette
Return status of last diskette operation
Read sector(s) from diskette
Write sector(s) to diskette
Verify sector(s) on diskette
Format track
on
diskette
Read drive parameters
Read DASD type
Diskette change line status
31.