13-sol - 13 C H A P T E R I/O Systems Practice Exercises...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 13 C H A P T E R I/O Systems Practice Exercises 13.1 State three advantages of placing functionality in a device controller, rather than in the kernel. State three disadvantages. Answer: Three advantages: Bugs are less likely to cause an operating system crash Performance can be improved by utilizing dedicated hardware and hard-coded algorithms The kernel is simplified by moving algorithms out of it Three disadvantages: Bugs are harder to fix—a new firmware version or new hardware is needed Improving algorithms likewise require a hardware update rather than just a kernel or device-driver update Embedded algorithms could conflict with application’s use of the de- vice, causing decreased performance. 13.2 The example of handshaking in Section 13.2 used 2 bits: a b usy bit and a c ommand-ready bit. Is it possible to implement this handshaking with only 1 bit? If it is, describe the protocol. If it is not, explain why 1 bit is insufficient. Answer: It is possible, using the following algorithm. Let’s assume we simply use the busy-bit (or the command-ready bit; this answer is the same regardless). When the bit is off, the controller is idle. The host writes to data-out and sets the bit to signal that an operation is...
View Full Document

Page1 / 4

13-sol - 13 C H A P T E R I/O Systems Practice Exercises...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online