What are the advantages of using the same system-call interface for manipulating both files and devices?

Answer 1

Each device can be accessed as though it was a file in the file

system. Since most of the kernel deals with devices through this file interface,

it is relatively easy to add a new device driver by implementing

the hardware-specific code to support this abstract file interface. Therefore,

this benefits the development of both user program code, which

can bewritten to access devices and files in the samemanner, and device

driver code, which can be written to support a well-defined API. The

disadvantage with using the same interface is that it might be difficult

to capture the functionality of certain devices within the context of the

file access API, thereby either resulting in a loss of functionality or a loss

of performance. Some of this could be overcome by the use of ioctl operation

that provides a general purpose interface for processes to invoke

operations on devices.