Ch 13 Multiprocessor and Multicomputer Organisation

Question 1

What is a multiprocessor?

Answer 1

Its a system that has multiple processors which share memory

SHARES RAM

Question 2

What is a multicomputer

Answer 2

System with multiple processors which don’t share the same memory

Question 3

what is Flynn’s taxonomy?

Answer 3

its a classification of computer architectures

Question 4

How is Flynn’s taxonomy classified?

Answer 4

By the number of instruction streams ad the number of data streams

Question 5

What is SISD?

Answer 5

Single instruction stream, single data Stream

Its a sequential computer that has no parallelism in either the instruction or data streams.

Examples include microprocessor

Question 6

Close coupled

Answer 6

The multiprocessor system that is our computer is close coupled.
little distance between RAM and processors. Those connetions are parallel connections

Question 7

Multicomputer

Answer 7

loosely coupled.
computers joined to each other using serial port (Ethernet)
Distances are much larger

speeds are much slower

Question 8

Common Definitions of multiprocessing/multicomputing system:

Answer 8

There has to be some memory that multiple processors can read and write to (SHARED STATE)

Processors must fail independently

Has to appear to the users as a single system.

Question 9

SIMD

Answer 9

solving an equation for every element.
e.g. solving an equation over and over again

one instruction is executed on multiple pieces of data

Not Commonly Used. Largely extinct.

Question 10

How to connect your nodes?

Answer 10

Best way to connect your nodes is to have them in the configuration you need depending on the problem you need to solve. Increases computational efficiency.

Question 11

Multiple instruction, single data

Answer 11

Doesn’t exist

Perform different instructions on the same data

Question 12

MIMD

Answer 12

Whole bunch of computers

CPU, Memory, IO

Question 13

Tightly Coupled

Answer 13

means parallel buses, short, high speed, high rate of info transfer

Question 14

loosely coupled

Answer 14

slower rates of data transfer, more physical distance between computers. therefore buses need to be serial

Question 15

are multiprocessors normally tightly or loosely coupled?

Answer 15

Tightly Coupled

Question 16

Are multicomputers tightly or loosely coupled?

Answer 16

Loosely coupled

Question 17

Multiprocessor interconnections can be the following:

Answer 17

Bussed or Switched

Question 18

What is a bussed interconnection?

Answer 18

Time Shared.
Only one bus write at any time

FOR SINGLE SHARED BUS
Only one processor can connect to a memory (or another processor) at one time-THERES A BOTTLENECK

FOR MULTIPLE BUSSES
Newmans architecture
Not all elements connect to all buses

Question 19

Switched interconnection

Answer 19

Isn’t static. the connections themselves change over time

Question 20

Are bussed system busses static or dynamic?

Answer 20

They’re dynamic.

Question 21

How do bussed systems work?

Answer 21

The elements connect and disconnect to the bus when they need to

Question 22

How to switched systems work? (CROSSBAR)

Answer 22

The busses themselves switch.
For each memory theres a bus, for each processor theres a bus.

Whether the buses connect to each other or not is due to the buses switching.

The point where they cross over is the cross bar switch

Question 23

Give 2 characteristics of Bussed Systems?

Answer 23

They are expensive and complicated.

Question 24

Theres another type of Switched System besides cross bar, what is it?

Answer 24

Omega Network

Built up of many layers of 2x2 switches. each switch is simpler than the whole of the crossbar switch