Computers and Architectures

Question 1

How are applications written

Answer 1

Applications are written using millions of lines of complex instructions

Question 2

What can hardware execute

Answer 2

Hardware can execute only a simple set of predefined instructions

Question 3

How many layers are needed to go from complex instructions to simple instructions

Answer 3

7

Question 4

What is the order of operations from high-level language to hardware

Answer 4

High level language,
Assembly language program (for MIPS)
Binary Machine language program (for MIPS)

Question 5

In the mid-1980s what was processor performance growth largely driven by

Answer 5

largely driven by technology

Question 6

What rate was processor performance growing in 1986

Answer 6

52%, or doubling every 2 years

Question 7

What was the growth in 1986 caused by

Answer 7

more advanced architectural and organizational ideas typified in RISC architectures

Question 8

What happened between 2003 and 2011 to processor performance

Answer 8

In 2003 the limits of power due to the end of Dennard scaling and the available instruction-level parallelism slowed uniprocessor performance to 23% per year until 2011

Question 9

What was the growth between 2011 and 2015 in processor performance

Answer 9

less than 12% or doubling every 8 years

Question 10

What caused the slowdown in growth between 2011 and 2015

Answer 10

in part due to the limits of parallelism of Amdahl’s Law

Question 11

Define Amdahl’s law

Answer 11

In other words, the performance improvement of a system as a whole is limited by its bottlenecks.

Question 12

Define Moore’s Law

Answer 12

Moore’s law is the observation that the number of transistors in an integrated circuit (IC) doubles about every two years.

Question 13

What is the growth currently

Answer 13

since 2015 just 3.5% per year or doubling every 20 years

Question 14

What are Personal Mobile Devices

Answer 14

Wireless devices with multimedia interface such as Smart phones and tablet computers

Question 15

What are the cons of personal mobile devices

Answer 15

o Cost
o Energy efficiency
o Size requirement
o Responsiveness & Predictability

Question 16

What are desktop computers

Answer 16

Low end notebooks to high end workstations,
battery operated laptops etc.

Question 17

What are the cons to desktop computers

Answer 17

Cost vs performance trade-offs mainly

Question 18

WHat are servers

Answer 18

Large scale and more reliable computing services
o Key features: Availability, Scalability, Throughput

Question 19

What is throughput

Answer 19

the amount of work done per unit of time

Question 20

What are cluster/wareshouse scale computers

Answer 20

SoftwareasaService(SaaS)likesocialnetworking,search,
multiplayer games, video sharing… has led to clusters.
o Largest clusters are termed as warehouse scale computers

Question 21

What are the cons of cluster/wareshouse scale computers

Answer 21

o Price-performance
o Power
o Availability just like servers
o Scalability through LANs

Question 22

What are embedded Computers

Answer 22

• Found in everyday machines; microwave ovens, washing machines,
  printers, ….
  o AlsofoundinNOTsocommonmachines;Aerospaceapplications, Nuclear, power plants,…

Question 23

What are the cons of embedded computers

Answer 23

o Cost
o Application-Specific Performance
o Energy Efficiency
o Reliability in remote operating conditions
o Temporal Correctness (sometimes)

Question 24

What did Micheal Flynn in 1966 propose

Answer 24

Flynn’s Taxonomy: a classification for exploitation techniques of application parallelism by the hardware.

Question 25

What were the 4 classes Micheal created

Answer 25

* Single instruction stream, single data stream (SISD) * Single instruction stream, multiple data streams (SIMD) * Multiple instruction streams, single data stream (MISD) * Multiple instruction streams, multiple data streams (MIMD)

Question 26

What is Single instruction stream, single data stream (SISD)

Answer 26

- Uniprocessor category o From programmer’s perspective, it is the standard sequential computer o Can exploit instruction-level parallelism o Use ILP techniques such as superscalar and speculative execution

Question 27

What is Single instruction stream, multiple data streams (SIMD)

Answer 27

Same instruction is executed by multiple processors o Used data streams are different o Exploits data-level parallelism by applying the same operations to multiple items of data in parallel o Each processor has its own data memory (hence the M D of SIMD)

Question 28

What is Multiple Instruction streams, Single Data stream (MISD)

Answer 28

No commercial multiprocessor of this type has been built to date, but it rounds out this simple classification

Question 29

What is Multiple instruction streams, multiple data streams (MIMD)

Answer 29

Each processor fetches its own instructions and operates on its own data o Targets task-level parallelism o More flexible than SIMD and more generally applicable o Inherently more expensive than SIMD

Question 30

What is RISC architecture

Answer 30

RISC architecture reduces the cycles per instruction while increasing the number of instructions per program.

Question 31

What is CISC architecture

Answer 31

CISC architecture reduces the number of instructions per program while increasing the number of cycles per instruction.

Question 32

What does it mean by RISC has a smaller and simple instruction set

Answer 32

- Fewer instructions - Fixed instruction length - Simple Operations

Question 33

What does it mean by RISC single cycle execution

Answer 33

Fast execution SImple control logic

Question 34

Why does RISK have fast execution

Answer 34

EachinstructioninaRISCprocessorisdesignedto execute in a single clock cycle, which leads to faster processing.

Question 35

Why does RISC have simple control logic

Answer 35

Theuniformityofinstructiontimingsimplifies the control unit of the CPU, reducing the complexity and improving speed.

Question 36

What is meant by load/store architecture

Answer 36

Only load and store instructions can access memory; all other instructions operate on registers

Question 37

What are the key charateristics of RISC

Answer 37

Small and simple instruction set

Question 38

in RISC what does its large register set do

Answer 38

reduces the need to access slower main memory

Question 39

What does RISC efficient pipelining mean

Answer 39

Instructions are optimized for pipelining, allowing high throughput.

Question 40

What does RISC simple addressing modes mean

Answer 40

Limited and straightforward memory addressing modes.

Question 41

What does RISC Compiler Optimization mean

Answer 41

Relies on compilers for efficient instruction scheduling and optimization.

Question 42

What Does RISC no microcode allow for

Answer 42

Executes instructions directly in hardware without needing microcode.

Question 43

What does RISC high instruction throughput allow for

Answer 43

High-speed instruction execution due to pipelining and load/store architecture.

Question 44

What does RISC uniform instruction format allow for

Answer 44

Fixed-length instructions make decoding simpler and faster.

Question 45

What are the classes of computers classified by functionality

Answer 45

* Personal Mobile Devices (PMDs) * Desktop computers * Servers * Cluster/warehouse scale computers * Embedded computers

Question 46

What does RISC stand for

Answer 46

Reduced Instruction Set Computing

Question 47

What does CISC stand for

Answer 47

Complex Instruction Set Computing

Question 48

What does pipelining refer to in RISC architecture

Answer 48

A technique that allows multiple instructions to be processed simultaneously at different stages

Question 49

True or False: RISC architectures typically avoid complex, specialized instructions.

Answer 49

True

Question 50

What role do compliers play in RISC architectures

Answer 50

Relies on compilers for efficient instruction scheduling and optimization

Question 51

What is the function of Microcode in RISC

Answer 51

Executes instructions directly in hardware without needing microcode