The functions in this category provide direct access to the BIOS interrupt services. They are all declared in BIOS.H.
| Routine | Use |
| _bios_disk | Issues service requests for both hard and floppy disks, using INT 0x13 |
| _bios_equiplist | Performs an equipment check, using INT 0x11 |
| _bios_keybrd | Provides access to keyboard services, using INT 0x16 |
| _bios_memsize | Obtains information about available memory, using INT 0x12 |
| _bios_printer | Performs printer output services, using INT 0x17 |
| _bios_serialcom | Performs serial communications tasks, using INT 0x14 |
| _bios_timeofday | Provides access to system clock, using INT 0x1A |
Note:
BIOS routines are hardware dependent. Some of them may not work as expected on machines whose hardware differs from the IBM PC.