COMS 465:Computer Mediated Communication

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Review

Computer Hardware

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Review

Computer Mediated Communication

Two technological components:

computers networks

Review - History of Computing

Review

Mechanical Computers

Review

Computer Generations

1st Generation (1950s)

Vacuum Tubes

Machine Language

UNIVAC

2nd Generation (1960’s)

Transistors

High-Level Languages

Standards (ASCII)

IBM System/360

Computer Generations

3rd Generation (mid 1960’s - mid 1970’s)

Integrated Circuit (IC)

Timesharing

Networking Standards

Two “Laws” of computer performance

Moore’s Law

Metcalf’s Law

Review

Computer Generations

4th Generation (1975+)

Microprocessor (1972)

VLSI = more than 5000 transistors on a chip

Invented by Dr. Ted Hoff of Intel

Intel 4004

PC Revolution

MITS Altair

Apple I & II

Review

Computer Generations

5th Generation

Quantum Computers

Molecular Computers

Review

Slides online

Review

Today

Computer Hardware

Computer Definitions

Computer = (n.) a device that computes

Computing = (v.) to represent data in a physical object of some kind and get a result by manipulating this object in some way

4 basic operations of all “computers”

Input

Processing

Output

Storage

IPOS cycle

Computer

Computer System

Hardware

Physical components; elements of the IPOS Cycle

“The part of a computer that you can kick”

Software

Programs or Applications

Indicate how the physical components operate

Control the IPOS Cycle

Computer

IPOS cycle - Input

Computer

IPOS cycle - Input

Keyboard

Microphone

Mouse

Scanner

Computer

IPOS cycle - Processing

Computer

IPOS cycle - Processing

Microprocessor

Central Processing Unit (CPU)

Computer

IPOS cycle - Output

Computer

IPOS cycle - Output

Monitor

Speakers

Printer

Computer

IPOS cycle - Storage

Computer

IPOS cycle - Storage

RAM/ROM

Hard Drive

USB Drive

CD /DVD

How Computers Work

Data Representation

Element of the IPOS

Input

Processing

Output

Storage

Data Representation

Analog / Digital

Analog – Encode data as a function

of changes of a continuous scale;

represented mechanically by spatial

differences across a ruler or gear or

electrically with voltage variations

Digital – Encode data as discrete

elements. Digital computers use two

discrete variables (0,1); represented

either mechanically by a two position

switch or electrically with changes in

voltage (on/off) or electric charge (+/-)

Data Representation

Digital

G. W. F. Leibniz

Binary numbers

Mathematics with 2 variables

George Boole

Boolean Algebra – Reduce all logical processing to three operations AND, OR and NOT

Digital Computer = series of logic gates. Operate according to

Boolean algebra to determine the value of an output signal

(one or zero).

Data Representation

Numbering system

Base or Radix

Every numbering system has a base

We count in base 10 - Count from 1-9

but after 9 you have to carry over into the next column

We use base 60 for clock time - Count

from 1-59 and then carry over into the

next column

Data Representation

Numbering system

Digital Computer

Computers only have two possible states by which to represent data - high or low power circuit

Digital computers use base 2 or binary numbers

Base 2

Count 0-1; at 2, carry over into the next column

Perfect system for computers

0 = low power circuit (off)

1 = high power circuit (on)

Data Representation

Numbering system

Bit = Binary Digit

Smallest unit of information a

computer can use

Values

In base 10, each place value is a

power of ten (10, 100, 1000...)

In base 2, each place value is a

power of 2 (2, 4, 8, 16, 32, 64…)

Data Representation

Numbering system

Byte

8 bits – 00110101

256 possibilities; baseline measure for data size

Data Representation

Character Codes

Translate between digital world of

the computer and the human world

of decimal numbers and letters

ASCII – American Standard Code for

Information Interchange

Examples

dog = 01100100 01101111 01100111

cat = 01100011 01100001 01110100

Binary encoder

Hardware

Input

How you get data into the computer

Transforms information into digital format

Hardware

Input Devices

Hardware

Biological Feedback Devices

Eye Tracking - Translates eye

movement into computer input

EEG Monitoring system Translates

brainwave states into computer input

Hardware

Hardware

Biological Feedback Devices

Brain Computer Interface (BCI)

Hardware

Processing

Central Processing Unit (CPU)

Data processing performance depends

upon the features of the CPU

Hardware

CPU Components

Control Unit

Arithmetic Logic Unit

Memory Unit

Hardware

CPU Operations

Fetch

Decode

Execute

Write Back

Microprocessors go through the four-steps of the

machine cycle millions of times per second

Hardware

CPU Performance

Data Bus Width

How much data can get into and out

of the processor at one time

Measured in bits: 32-bit, 64-bit, etc.

Clock Speed

The operating speed of a microprocessor, defined as the rate at

which it performs internal operations.

Expressed in cycles per second

(megahertz)

Year Chip Bus Width Clock Speed1971 4004 4-bit 740 KHz 1979 8088 8-bit 8 MHz1982 80286 16-bit 12 MHz1985 80386 32-bit 33 MHz1989 Intel-486 32-bit 100 MHz1993 Pentium 32-bit 200 MHz1998 Pentium2 32-bit 400 MHz1999 Pentium3 32-bit 450 MHz 2000 Pentium4 32-bit 1.4 GHz2006 Core Duo 32-bit 2.0 GHz2007 Core 2 Quad 64-bit 2.4 GHz2010 Core i7 64-bit 3.3 GHz

Hardware

Output

How you get data out of the computer

Transforms digital information into human

accessible form

Hardware

Output

How you get data out of the computer

Transforms digital information into human

accessible form

Hardware

Output

Video Adapters and Monitors

Printers

Sound Cards and Speakers

Haptic Output devices

Hardware

Output

Video Adapters

Generates the visual image

Quality of visual display

Resolution Color Depth

Hardware

Output

Monitors

Display video adapter’s output

Types

CRT - Cathode Ray Tube

LCD - Liquid Crystal Display

Hardware

Output

HMD – Head Mounted Display

Invented by Ivan Sutherland (1968)

Commercialization

Oculus Rift

Google Cardboard

Hardware

Output

Printers – 2d & 3d

Hardware

Output

Audio

Haptics (touch)

Hardware

Storage

Volatile

High data transfer rates

Memory contents are erased when

power is turned off

Non-volatile

Slower data transfer rates

Retains information when power is

turned off

Hardware

Storage

Read Only Memory (ROM-BIOS)

Random Access Memory (RAM)

Cache (CPU)

Disk Storage

Hardware

Storage

Device Access Speed Cost per MB

Cache Fastest Highest

RAM Fast High

Hard Disk Medium Medium

CD-ROM Slow Low

Floppy Disk Very Slow Lowest

Computer needs RAM to process data but it also needs Hard Disk and other

forms of non-volatile storage to store large programs and data files.

Memory

Storage

Summary

Computer Hardware

Data Representation

Hardware = Elements of

the IPOS Cycle

Input

Processing

Output

Storage

Preview

Computer Software

How you control the IPOS cycle

Texts/Activities

Timeline - Software & Languages

Sutcliffe - Hacking the Future (video)

Maker Exercise #1 - Code