hardware lesson

7/30/2019 Hardware Lesson

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Hardware LessonCS1313 Spring 2009 1

Hardware Outline1. Hardware Outline

2. What is a Computer?3. Components of a Computer

4. Categories of Computer Hardware

5. Central Processing Unit (CPU)

6. CPU Examples

7. CPU Parts

8. CPU: Control Unit

9. CPU: Arithmetic/Logic Unit

10. CPU: Registers11. How Registers Are Used

12. Multicore

13. Multicore History

14. Storage

15. Primary Storage

16. Cache

17. From Cache to the CPU

18. Main Memory (RAM)19. Main Memory Layout

20. RAM vs ROM

21. Speed => Price => Size

22. How Data Travel Between RAM and CPU

23. Loading Data from RAM into the CPU

24. RAM is Slow

25. Why Have Cache?26. Secondary Storage

27. Media Types

28. Speed, Price, Size

29. CD-ROM & DVD-ROM

30. CD-ROM & DVD-ROM: Disadvantage

31. CD-ROM & DVD-ROM: Advantages

32. Why Are Floppies So Expensive Per MB?

33. I/O34. I/O: Input Devices

35. I/O: Output Devices

36. Bits

37. Bytes

38. Words

39. Putting Bits Together

40. Putting Bits Together (contd)

41. Powers of 242. Powers of 2 vs Powers of 10

43. KB, MB, GB, TB, PB

44. Kilo, Mega, Giga, Tera, Peta

45. Moores Law

46. Implication of Moores Law

47. Double, double,


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What is a Computer?

[A] programmable electronic device

that can store, retrieve and process data.(N. Dale & D. Orshalick,

Introduction to PASCAL and Structured

Design,D.C. Heath & Co.,

Lexington MA, 1983, p. 2)


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Components of a Computer

Computer

HardwarePhysical Devices

SoftwareInstructions & Data

DONT PANIC!This discussion may be confusing at the moment;

itll make more sense after youve written a few programs.


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Categories of Computer Hardware

Central Processing Uni t(CPU) Storage

Primary: Cache, RAM

Secondary: Hard disk, removable (e.g., CD)

I /O

Input Devices

Output Devices


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Central Processing Unit (CPU)

The Central Processing Unit(CPU), also called theprocessor, is the brain of the computer.

Harpertown exteriorhttp://blogs.zdnet.com/Apple/images/intel-xeon.jpg

Intel Pentium4 Xeon Harpertown Quad Core

Innardshttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpg
http://blogs.zdnet.com/Apple/images/intel-xeon.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://media.arstechnica.com/reviews/hardware/mac-pro-2g-review.media/quadcoredie.jpghttp://blogs.zdnet.com/Apple/images/intel-xeon.jpghttp://blogs.zdnet.com/Apple/images/intel-xeon.jpghttp://blogs.zdnet.com/Apple/images/intel-xeon.jpg


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CPU Examples

Intel Pentium 4/AMD Athlon (Windows PCs) Intel Itanium2 (servers)

Qualcomm MSM (cell phones)

IBM POWER6 (servers) Sun UltraSPARC (servers)


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CPU Parts

Arithmetic/Logic UnitControl Unit Registers

Fetch Next Instruction Add Sub

Mult Div

And Or

Not

Integer

Floating Point

Fetch Data Store Data

Increment Instruction Ptr

Execute Instruction

The CPU consists of three main parts: Control Unit

Arithmetic/Logic Unit

Registers


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CPU: Control Unit

The Control Uni tdecides what to do next.For example:

memory operations: for example,

loaddata from

main memory(RAM) into the

registers;

storedata from the registers into main memory;

arithmetic/logical operations: e.g., add, multiply;

branch: choose among several possible courses of

action.


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CPU: Arithmetic/Logic Unit

The Ar ithmetic/Logic Unit(ALU) performsarithmetic and logical operations.

Arithmetic operations: e.g., add, subtract,

multiply, divide, square root, cosine, etc.

Logical operations: e.g., compare two numbers to

see which is greater, check whether a true/false

statement is true, etc.


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CPU: Registers

Registersare memory-like locations inside the CPUwhere data and instructions reside that are beingused right now.

That is, registers hold the operands being used by thecurrent arithmetic or logical operation, or the resultof the arithmetic or logical operation that was just

performed.

For example, if the CPU is adding two numbers, thenthe addend is in some register, the augend is inanother register, and after the addition is performed,the sum shows up in yet another register.

A typical CPU has only a few hundred to a fewthousand bytes of registers.


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How Registers Are Used

Every arithmetic or logical operation has one ormore operands and one result.

Operands are contained in registers (source).

A black box of circuits performs the operation.

The result goes into a register (destination).

Example:

addend in R0

augend in R1ADD sum in R2

5

712

Register Ri

Register Rj

Register Rk

operand

operand

result

Operation circuitry


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Multicore

A multicoreCPU is a chip with multiple,independent brains, known as cores.

These multiple cores can run completely separate

programs, or they can cooperate together to work

simultaneously in parallel on different parts of the

same program.

All of the cores share the same connection to

memoryand the same bandwidth (memoryspeed).


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Multicore History

Dual core: October 2005 Quad core: June 2006

Hex core: September 2008

Oct core: estimated late 2009http://www.intel.com/pressroom/kits/quickreffam.htm (dual, quad, hex)http://en.wikipedia.org/wiki/Intel_Nehalem_(microarchitecture) (oct)
http://www.intel.com/pressroom/kits/quickreffam.htmhttp://en.wikipedia.org/wiki/Intel_Nehalem_(microarchitecture)http://en.wikipedia.org/wiki/Intel_Nehalem_(microarchitecture)http://www.intel.com/pressroom/kits/quickreffam.htm


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Storage

There are two major categories of storage: Primary

Cache

Main memory (RAM)

Secondary

Hard disk

Removable (e.g., CD, floppy)


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Primary Storage

Primary storageis where data and instructions residewhen theyre being used by a program that is

currently running.

Typically is volatile: The data disappear when the

power is turned off.

Typically comes in two subcategories:

Cache

Main memory (RAM)


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Cache

Cachememory is where data and instructions residewhen they are going to be used very very soon, or

have just been used.

Cache is very fast (typically 20% - 100% of the

speed of the registers).

Therefore, its very expensive (e.g., $5 per MB)http://www.pricewatch.com/

Therefore, its very small (e.g., 1/4

MB to 12 MB)

but still much bigger than registers.
http://www.pricewatch.com/http://www.pricewatch.com/


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From Cache to the CPU

Typically, data move between cache and the CPU at speeds

comparable to that of the CPU performing calculations.

CPU

Cache

253 GB/sec (72%) on a1.83 GHz Pentium4 Core Duo

351 GB/sec on a1.83 GHz Pentium4 Core Duo

http://www.dell.com/
http://www.dell.com/http://www.dell.com/


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Main Memory (RAM)

Main memory(RAM) is where data and instructionsreside when a program that is currently runningis going to use them at some point during the run(whether soon or not).

Much slower than cache(e.g., about 1-5% of CPU speed for RAM,vs 20-100% of CPU speed for cache)

Therefore, much cheaper than cache

(e.g., $0.03/MB for RAM vs $5/MB for cache) Therefore, much larger than cache

(e.g., 1-32 GB for RAM vs1/4 MB to 12 MB for cache)


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Main Memory Layout

Main memory is made upoflocations, also knownas cells.

Each location has aunique integeraddress

that never changes.Each location has avaluealso knownas the contentsthat the CPU canlook at and change.

We can think ofmemory as onecontiguouslineof cells.


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RAM vs ROM

RAM: Random Access Memory

Memory that the CPU can look at and changearbitrarily (i.e., can load from or store into anylocation at any time, not just in a sequence).

We often use the phrases Main Memory, Memoryand RAM interchangeably.

Sometimes known as corememory, named for anolder memory technology. (Note that this use of

the word core is unrelated to dual core.)ROM: Read Only Memory

Memory that the CPU can look at arbitrarily, butcannot change.


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Speed => Price => Size

Registers are VERY fast, because they are etcheddirectly into the CPU.

Cache is also very fast, because its also etched intothe CPU, but it isnt directly connected to the ControlUnit or Arithmetic/Logic Unit. Cache operates atspeeds similar to registers, but cache is MUCH biggerthan the collection of registers (typically on the orderof 1,000 to 10,000 times as big).

Main memory (RAM) is much slower than cache,because it isnt part of the CPU; therefore, its muchcheaperthan cache, and therefore its much biggerthan cache (for example, 1,000 times as big).


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How Data Travel Between RAM and CPU

CPUThe bus is theconnection from the

CPU to main memory;

all data travel along it.

For now, we canthink of the bus as a

big wire connecting

them.


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Loading Data from RAM into the CPU


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RAM is Slow

CPU

10.66 GB/sec (3%)ftp://download.intel.com/design/Pentium4/papers/24943801.pdf

351 GB/sec on a

1.83 GHz Pentium4Core DuoRichard Gerber, The Software Optimization Cookbook: High-performance

Recipes for the Intel Architecture. Intel Press, 2002, pp. 161-168.

Bottleneck

The speed of data transfer

between Main Memory andthe CPU is much slower thanthe speed of calculating, sothe CPU spends most of itstime waiting for data to comein or go out.
ftp://download.intel.com/design/Pentium4/papers/24943801.pdfftp://download.intel.com/design/Pentium4/papers/24943801.pdf


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Why Have Cache?

CPUCache is nearly the samespeed as the CPU, so theCPU doesnt have to waitnearly as long for stuffthats already in cache: itcan do more operations

per second!

253 GB/sec (72%)http://www.anandtech.com/showdoc.html?i=1460&p=2

10.66 GB/sec (3%)ftp://download.intel.com/design/Pentium4/papers/24943801.pdf

351 GB/sec on a

1.83 GHz Pentium4Core DuoRichard Gerber, The Software Optimization Cookbook: High-performance

Recipes for the Intel Architecture. Intel Press, 2002, pp. 161-168.
http://www.anandtech.com/showdoc.html?i=1460&p=2ftp://download.intel.com/design/Pentium4/papers/24943801.pdfftp://download.intel.com/design/Pentium4/papers/24943801.pdfhttp://www.anandtech.com/showdoc.html?i=1460&p=2


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Secondary Storage

Where data and instructions reside that are going tobe used in the future

Nonvolatile: data dont disappear when power is

turned off.

Much slower than RAM, therefore much cheaper,

therefore much larger.

Other than hard disk, most are portable: they can be

easily removed from your computer and taken tosomeone elses.


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Media Types

Magnetic: Always can be read

Always can be written and rewritten multiple times

Contents degrade relatively rapidly over time

Can be erased by magnets

Optical Always can be read

Some can be written only once, some can be rewrittenmultiple times

Contents degrade more slowly than magnetic media Cant be erased by magnets

Paper: forget about it!


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Speed, Price, Size

Medium Speed

(MB/sec)

Size

(MB)

Media

Type

Can write

to it?

Port-

able?

Pop-

ular?

Drive

cost ($)

Media cost

($/MB)Cache 269,257 12 L2/L3 Y N Reqd $5

RAM 21,328 32,768 DDR2 Y N Reqd $0.03

Hard Disk 100 1,500,000 Mag Y N Reqd $0.0001

Blu-ray 17 25,000 Opt Y Y Soon $120 $0.0002

DVD+RW 16 8500 Opt Y Y Y $24 $0.00003

CD-RW 7.6 700 Opt Y Y Y $14 $0.0002

Mag tape 15 800,000 Mag Y Y N $2000 $0.00006

Floppy 0.03 1.44 Mag Y Y Y $9 $0.09

Cassette


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CD-ROM/DVD-ROM/BD-ROM

When a CD or DVD or Blu-ray holds data instead ofmusic or a movie, it acts very much like Read Only

Memory (ROM):

it can only be read from, but not written to;

its nonvolatile;

it can be addressed essentially arbitrarily (its not

actually arbitrary, but its fast enough that it might

as well be).


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CD-ROM/DVD-ROM/BD-ROM: Disadvantage

Disadvantage of CD-ROM/DVD-ROM/BD-ROMcompared to ROM: speed.

CD-ROM/DVD-ROM/BD-ROM are much slower

than ROM.

CD-ROM is 7.6 MB/sec (peak); DVD-ROM is 16

MB/sec; BD-ROM is 17 MB/sec.

Most ROM these days is 21,328 MB/sec (1200+ times

as fast as DVD or Blu-ray and 2800 times as fast as

CD).


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CD-ROM & DVD-ROM: Advantages

Advantages of CD-ROM/DVD-ROM compared toROM:

CD-ROM and DVD-ROM are much cheaper thanROM.

Blank CDs and blank BDs are roughly $0.0002 per MB;blank DVDs are roughly $0.00003 per MB.

ROM is even more expensive than RAM (which is$0.03/MB), because it has to be made special.

CD-ROM and DVD-ROM are much largertheycan have arbitrary amount of storage (on manyCDs or DVDs); ROM is limited to a few GB.


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Why Are Floppies So Expensive Per MB?

CD-RWs cost roughly $0.0002 per MB, but floppydisks cost about $0.09 per MB, 450 times as

expensive per MB. Why?

Well, an individual CD has much greater capacity

than an individual floppy (700 MB vs. 1.44 MB),and the costs of manufacturing the actual physical

objects are similar.

So, the cost of a floppy per MB is much higher.


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I/O

We often sayI /O

as a shorthand forInput/Output.


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I/O: Input Devices

We often sayI /O


I nput Devicestransfer data into computer (e.g., from

a user into memory).

For example: Keyboard

Mouse Scanner

Microphone Touchpad

Joystick


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I/O: Output Devices

We often sayI /O


Output Devicestransfer data out of computer (e.g.,

from memory to a user).

For example: Monitor

Printer

Speakers


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Bits

Bit(Binary digIT) Tiniest possible piece of memory. Made of teeny tiny transistors wired together.

Has 2 possible values that we can think of in

several ways: Low or High: Voltage into transistor Off or On: Conceptual description of transistor state

False or True: Booleanvalue for symbolic logic

0 or 1: Integer value

Bits arent individually addressable: the CPU cantload from or store into an individual bit ofmemory.


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Bytes

Byte: a sequence of 8 contiguous bits (typically) On most platforms(kinds of computers), its the

smallest addressablepiece of memory: typically,

the CPU can load from or store into an individual

byte.

Possible integer values: 0..255 or -128..127 (to be

explained later)

Can also represent a character (e.g., letter, digit,punctuation; to be explained later)


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Words

Word: a sequence of 4 or 8 contiguous bytes(typically); i.e., 32 or 64 contiguous bits

Standard size for storing a number (integer or

real)

Standard size for storing an address (special kind

of integer)


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Putting Bits Together

1 bit: 21

= 2 possible values: or2 bits: 22 = 4 possible values

3 bits: 23 = 8 possible values

0 1

0 0 0 01 1 1 1

0 0 0 0 0 1 0 1 10 0 1

1 0 0 1 0 1 1 1 0 1 1 1


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Putting Bits Together (contd)

4 bits: 24

= 16 possible values

8 bits: 28 = 256 possible values

10 bits: 210 = 1,024 possible values

16 bits: 216 = 65,536 possible values

32 bits: 232 = 4,294,967,296 possible values

(typical size of an integer in most computers today)


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Powers of 2

20 = 1 211 = 2,048

21 = 2 212 = 4,096

22 = 4 213 = 8,192

23 = 8 214 = 16,384

24 = 16 215 = 32,76825 = 32 216 = 65,536

26 = 64 217 = 131,072

27 = 128 218 = 262,144

28 = 256 219 = 524,288

29 = 512 220 = 1,048,576

210 = 1,024 (about a thousand)

(about a million)


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Powers of 2 vs Powers of 10

A rule of thumb for comparing powers of 2to powers of 10:

210 ~ 103

So:

210 ~ 1,000 (thousand) 220 ~ 1,000,000 (million)

230 ~ 1,000,000,000 (billion)

2

40

~ 1,000,000,000,000 (trillion) 250 ~ 1,000,000,000,000,000 (quadrillion)

260 ~ 1,000,000,000,000,000,000 (quintillion)


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KB, MB, GB, TB, PB

Kilobyte(KB): 210 bytes, which is approximately

1,000 bytes (thousand)

Megabyte(MB): 220 bytes, which is approximately

1,000,000 bytes (million)

Gigabyte(GB): 230 bytes, which is approximately

1,000,000,000 bytes (billion)

Terabyte(TB): 240 bytes, which is approximately

1,000,000,000 bytes (trillion)

Petabyte(PB): 250 bytes, which is approximately

1,000,000,000,000,000 bytes (quadrillion)

Exabyte(EB): 260 bytes, which is approximately

1,000,000,000,000,000,000 bytes (quintillion)


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Kilo, Mega, Giga, Tera, Peta

Kilobyte (KB): 210 bytes = 1,024 bytes ~ 1,000 bytes

Approximate size: one e-mail (plain text)

Desktop Example: TRS-80 w/4 KB RAM (1977)

Megabyte (MB): 220 bytes = 1,048,576 bytes ~ 1,000,000 bytes

Approximate size: 30 phonebook pages

Desktop Example: IBM PS/2 PC w/1 MB RAM (1987)Gigabyte (GB): 230 bytes = 1,073,741,824 bytes ~ 1,000,000,000 bytes

Approximate size: 15 copies of the OKC white pages

Desktop: c. 1997

Terabyte (TB): 240 bytes = 1,099,511,627,776 bytes ~ 1,000,000,000,000 bytes

Approximate size: 5,500 copies of a phonebook listing everyone in the world

Desktop: ??? (Jan 2009: 32 GB)

Petabyte (PB): 250 bytes ~ 1,000,000,000,000,000 bytes

Desktop: ???


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Moores Law

Moores Law: Computing speed and capacity double every18 to 24 months.

In 1965 Gordon Moore (Chairman Emeritus, Intel Corp)observed the doubling of transistor density on amanufactured die every year.

People have noticed that computing speed and capacity areroughly proportional to transistor density.

Moores Law is usually hedged by saying that computingspeed doubles every 18-24 months (typically 18).

See:http://www.intel.com/technology/mooreslaw/

http://www.intel.com/pressroom/kits/quickreffam.htm
http://www.intel.com/technology/mooreslaw/http://www.intel.com/pressroom/kits/quickreffam.htmhttp://www.intel.com/pressroom/kits/quickreffam.htmhttp://www.intel.com/technology/mooreslaw/


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Implication of Moores Law

If computing speed and capacity double every 18months, what are the implications in our lives?

Well, the average undergrad student isto one

significant figureabout 20 years old.

And the average lifespan in the USto one

significant figureis about 80 years.

So, the average undergrad student has 60 years to go.

So how much will computing speed and capacityincrease during the time you have left?


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Hardware Lesson

Double, double,

60 years / 18 months = 40 doublingsWhat is 240?

Consider the computer on your desktop today,

compared to the computer on your desktop the dayyou die.

How much faster will it be?

Can we possibly predict what the future of computingwill enable us to do?

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