Device Drivers

Question 1

What is the key purpose of device drivers

Answer 1

To provide uniform access to physical devices for all devices of a given class. I.e. all keyboards can be interfaced the same

Question 2

As well as read write requests, what is the role of device drivers

Answer 2

Device drivers must:
- Initialize the device
- Manage the power supply of the device
- Protect the device from harmful commands
- Deal with availability - i.e. is the device hot-pluggable

Question 3

Where do device drivers run

Answer 3

In the kernel space, as they need to access I/O registers and need privileged access to do this

Question 4

Who, most often, makes device drivers

Answer 4

The device manufacturer

Question 5

Device drives provide an abstraction of physical devices to simplify programming and allow reuse of code, what can be a drawback of this

Answer 5

This abstraction can get in the way of optimization as physical devices may differ from the abstract model assumed by the OS

Question 6

What would be the first step to writing a driver

Answer 6

Look at the datasheet of the device and learn what commands are available, reading the sample code at the same time