## Input/Output Device Driver Reference

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### Parallel Port Device Driver

The OS/2 parallel port device driver is a base physical device driver that supports the parallel port device interface for OS/2. There are two distinct versions of the parallel port device driver:

PRINT01.SYS Supporting parallel port adapters on ISA/EISA bus machines
PRINT02.SYS Supporting parallel port adapters on Micro Channel machines ( machines containing Micro Channel architecture).

PRINT01.SYS manipulates the hardware ports through I/O instructions. The Micro Channel parallel port device driver does not access the hardware ports. Advanced BIOS (ABIOS), which executes on Micro Channel machines, replaces the hardware port manipulation done on the ISA/EISA bus machines.

Only one of these physical device drivers will be resident for each machine running in OS/2. Because the parallel port device driver is a base physical device driver, OS/2 determines the system's hardware configuration and automatically installs and initializes the appropriate physical device driver. OS/2 adds a BASEDEV= statement for the device driver to the CONFIG. SYS file.