Ch. 1 PPT

Question 1

What does an OS do?

Answer 1

Exploits processor HW resources, provides a set of system services, and manages secondary memory and IO devices

Question 2

Basic components of a PC

Answer 2

Processor, main memory, IO modules, and the System Bus

Question 3

What does the processor do?

Answer 3

Control operation of the computer and performs data processing

Question 4

What is main memory?

Answer 4

The temporary memory, it is wiped clean every time the system shuts down.

Question 5

What do IO modules do?

Answer 5

Move data between computer and external environments… HDD, communications equipment, and terminals

Question 6

What does the System bus do?

Answer 6

Provides communication among processors, main memory, and IO modules

Question 7

What is a microprocessor?

Answer 7

An invention that brought about desktop and handheld computing. The processor is on a single chip and it is fast for general purpose.

Question 8

What is a GPU?

Answer 8

Does computation on single instruction multiple data techniques. Used for numerical processing, physics simulation, and computations on large data sets.

Question 9

What is a Digital Signal Processor?

Answer 9

Handles streaming signals. Used to be found in modems,. Can decode and encode speech and video (codecs).

Question 10

What is a system on a chip?

Answer 10

DSP, GPU, main memory, CPUs, and caches on one chip for mobile devices

Question 11

How does a processor execute an instruction?

Answer 11

Fetches the instruction from memory and executes it

Question 12

What does the program counter do?

Answer 12

Hold the address of the next instruction

Question 13

What does the instruction register do?

Answer 13

Holds the current instruction. it is interpreted and then executed.

Question 14

What would a control operation be?

Answer 14

Changing the order in which instructions are to be executed.

Question 15

What is an interrupt?

Answer 15

Something that changes the execution by the processor. Aimed at making things more efficient

Question 16

Program Interrupt

Answer 16

Usually caused by an execution error, like and overflow or a divide by zero

Question 17

Timer Interrupt

Answer 17

Generated by a timer in the processor. Allows the OS to do something on a regular interval.

Question 18

IO Interrupt

Answer 18

Sent to the processor by an IO device, can be an error or signaling that something was completed successfully.

Question 19

Hardware Failure Interrupt

Answer 19

Caused when there is a hardware failure like bad memory or a power failure

Question 20

What happens if there are multiple interrupts?

Answer 20

Disable interrupts while another interrupt is being process, or implement an interrupt hierarchy

Question 21

What are some memory constraints?

Answer 21

It’s expensive, and its speed: meaning it has to be able to keep up with the processor.

Question 22

What is the general trade off of memory?

Answer 22

The more you have, the slower it is. The less you have, the more expensive it is but its faster

Question 23

What is Locality?

Answer 23

Putting clusters of data into levels, such that the higher levels are accessed more frequently than the lower levels.

Question 24

What is secondary memory?

Answer 24

The more permanent memory, like a hard disk.

Question 25

What is the cache?

Answer 25

The fastest memory within the processor, used to exploit locality. Used to interacted between the processor and the main memory. Three levels.

Question 26

What is block size?

Answer 26

The unit of data exchanged between cache and main memory

Question 27

What does the mapping function do?

Answer 27

Determine where the block will be located in the cache. A design constraint is how long a block can stay in cache and the hardware cost of this function.

Question 28

Least Recently Used Algorithm

Answer 28

Replaces unused blocks in the cache. Hardware is needed to determine what is most unused.

Question 29

What is write policy?

Answer 29

Dictates when memory write operations can occur

Question 30

What is programmed IO?

Answer 30

IO operations are performed periodically until an instruction is complete. Severely impacts performance of the entire system.

Question 31

What is interrupt driven IO?

Answer 31

The IO module sends an interrupt to the processor when it is ready to do something. Still requires a lot of overhead.

Question 32

Direct Memory Access IO?

Answer 32

The IO module is given direct access to the memory and the processor is only involved at the beginning and and of the transfer.

Question 33

Symmetric Multiprocessors vs. Multicore

Answer 33

In symmetric, there are multiple processors sharing system resources. In multicore, there are multiple cores on a single die, still sharing resources.