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ALL THINGS DIGITAL.

Everything is evolving to being digital.

- Telephone, radio, etc

Convergence – process by which several technologies with different functionalities evolve to form a

single product.

Eg. Cellphones – it has overlapping features

Why does convergence take so long?

- Technology sometimes outstrips society’s ability to deal with it.

- Laws and customs change slowly

SECTION A: DIGITAL SOCIETY

How does DIGITAL TECHNOLOGY affect freedom & democracy?

- “freedom of expression/speech is NOT absolute; hate, violence, porn

- Makes it easy to cross cultural & geographical boundaries (TV, News etc)

- Anonymizer tools; cloaks person’s identity

- Internet Info acceptable in some cultures may not be in others

There are a lot of attempts made to censor & filter speech on the internet

Has DIGITAL TECHNOLOGY changed the way we view privacy?

- Diminish privacy

How does DIGITAL TECHNOLOGY influence property?

Intellectual property: ownership of certain types of information, ideas or presentations

What effect does Digital Technology have on economy?

- Consumers access a wide variety of products

- Gap between people who have access to digital technology and those that do not

Learning and understanding Digital Technology makes us aware of issues related to privacy, security,

freedom of speech and intellectual property.

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SECTION B: DIGITAL DEVICES

Computer Basics

What is a computer?

- Electronic, digital multipurpose device that accepts input, process data, stores data and

produces output, all according to a series of stored instructions.

What is input?

- Whatever is submitted or transmitted to a computer system

What is output?

- Result produced by a computer

What does computer data mean?

- SYMBOLS that represent facts, objects & ideas

What does process data mean?

- Manipulation of data (this includes modigying)

Where does processing take place?

- Central Processing Unit (CPU)

What is CPU?

- It is a microprocessor. A microprocessor is an electronic component/part that can be

programmed to perform/do tasks based on the data it receives

- It is also known as the process or the BRAIN of a digital device.

How do computers store data?

- Most computers use more than one place to put data. MEMORY – area that temporarily holds

data (waiting to be processed, stored or output). STORAGE – area where data can be left on a

permanent basis.

- Data is stored in FILES. FILE – named collection of data that exists on a storage medium.

- STORAGE MEDIUM – hard disks, floppy disks, DVD, CD, Flash drive etc.

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What’s so significant/important about a computer’s ability/power to store instructions?

The series of instructions that tells a computer how to carry out processing task is called a COMPUTER

PROGRAM or PROGRAM. Programs form SOFTWARE. When a computer runs software, it

performs/does the instructions to carry out a task.

Why do we store programs in a computer?

Stored programs can be loaded into the computer’s memory, and replaced when the computer

performs another task. This makes computers multipurpose machines.

What kinds of software do computer run?

Two main types

i. Application Software – set of computer programs that helps a person/user carry out a task

Example – Microsoft Office

ii. System Software – set of computer programs that help the computer system monitor itself

in order to function efficiently.

Example – Operating System (master controller for all activities that take place within a

computer. It helps us indirectly by starting programs and locating data files.

Are computer categorized?

- Nowadays, they are grouped according to criteria such as usage, cost, size and capability.

Experts do not necessarily agree on the categories or the devices placed in each category, but

commonly used computer categories include

i. Personal computers

ii. Servers

iii. Mainframes

iv. supercomputers

What is a personal computer?

- Microprocessor-based computing device designed to meet the computing needs of an

individual. They are available as desktop or portable models.

What is a workstation?

-

- – ordinary computer that is connected to a network. Second meaning – powerful desktop

computer used for high-performance tasks, that require a lot of processing speed. Some

workstation contain more than one microprocessor.

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Is an Xbox a personal computer?

- Today videogame consoles/supports contain microprocessors

- Add-ons allows Xbox to play DVD, users to send and receive emails etc. Yet it is NOT considered

a replacement for a personal computer.

What makes a computer a SERVER?

- The purpose of a server is to serve computers on a network (Internet or home network) by

supplying them with data.

- Any software or digital device such as a computer that requests data from a server is called a

CLIENT.

- Any computer can be configured to work as a server depending of the data it serves. Other

computers are manufactured specfically to work as a server.

Mainframe computers – large and expensive capable of simultaneously processing data for hundres or

thousands of users. Generally used by businesses or governments to provide centralized storage,

processing and management for large amount of data.

Super computers – one of the fastest computers in the world. It can tackle compute-intensive problems.

Compute-intensive problem – problem that requires massive amounts of data to be processed using

complex mathematical calculations. Example - Molecular calculations, atmospheric models, and climate

research.

Most supercomputers’ CPU are constructed from thousands of microprocessor.

PDA, Smart Phones, and Portable Media Players

- They incorporate computer characteristics. Technically these devices could be classified as

computers, but they are referred to by function.

Microcontrollers – special-purpose microprocessor that is built into the machine it controls. Sometimes

called a computer-on-a-chip. It could be classified as a computer but in practice they are used for

dedicated applications not as multipurpose devices.

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SECTION C: DIGITAL REPRESENTATION

DATA REPRESENTATION BASICS

What is data?

- Symbols that represent things. It can be a number, color, or notes on a musical composition

What is information?

- Data becomes information when it is presented in a format that people can understand and use.

What is data representation?

- Refers to the form in which data is stored, processed, and transmitted. Data can be represented

using digital or analog methods.

What’s the difference between analog and digital?

Digital data – text, numbers, graphics, sound and video that has been converted into discrete digits

such as 0s and 1s.

Analog data – is represented using an infinite scale of values.

How does digital data work?

i. Digital devices are electronic, so you can imagine data flowing within these devices as pulses

of light.

ii. Digital signals can be represented by 2 different voltages, such as +5 volts or 0 volts.

iii. It can also be represented by two different tones as they flow over a phone line.

iv. It can also take the form of light and dark spots etched on the surface of a CD or positive and

negative orientation of magnetic particles on the surface of a hard disk.

REGARDLESS OF TECHNOLOGY, however, digital data is ALWAYS REPRESENTED BY TWO

STATES DENOTED/SYMBOLIZED BY 0 and 1

Binary digits (bits) – 0s & 1s used to represent digital data

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REPRESENTING NUMBERS, TEXT, AND PICTURES

How do digital devices represent numbers?

1. Numeric data – consists of numbers that might be used in arithmetic operations

Binary Number System – has only two digits: 0 and 1

(This is different from the familiar decimal system. When we reach 9, we run out of digits, and for

ten we use digits 10, where zero is a placeholder and the 1 indicates a group of tens)

Decimal Binary

(Base 10) (Base 2) 0 0 1 1 2 10 3 11 4 100 5 101 6 110 7 111 8 1000 9 1001 10 1010 11 1011 12 1100 13 1101

How do digital devices represent words and letters?

2. Character data – composed of letters, symbols, and numbers that are not used in arithmetic

operations.

Example.

Some of the codes digital data use to represent character data.

i. ASCII – requires only seven bits for each character (128 characters)

ii. Extended ASCII – uses 8 bits to represent each character (256 characters)

iii. EBCDIC – an alternative to the 8 it Extended ASCII code used only by older, IBM

mainframe computers

iv. Unicode – uses 16 bits (provides codes for 65,000 characters)

H I !

01001000 01001001 0010001

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Why do ASCII and Extended ASCII provide codes for 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9?

- For numbers that are not used in calculations

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How can bits be used to store images?

- Images can be digitized by treating them as series of colored dots. Each dot is assigned a binary

number according to its color. Example; green dot – 0010, red dot – 1100

How can bits be used to store sound?

- Sound such as music and speech can be characterized by properties of wave. You can represent

sound wave digitally by sampling it at various points and then converting those point into digital

numbers.

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QUANTIFYING BITS AND BYTES

Bits (b) – binary digits. Usually express transmission speeds.

Byte (B) – a group of 8 bits. Usually express storage space.

Important Terminology.

Bit One binary digit Gigabit 230 bits

Byte 8 bits Gigabyte 230 bytes Kilobit 1,024 or 210 bits Terabyte 240 bytes Kilobyte 1,024 or 210 bytes Petabyte 250 bytes Megabit 1,048,576 or 220 bits Exabyte 260 bytes Megabyte 1,048,576 or 220 bytes

CIRCUITS AND CHIPS

How do digital devices store and transport all those bits?

- Because most digital devices are electronic, bits take the form of electrical pulses that can travel

over circuits in much the same way that electricity flows over a wire when you turn on a light

switch. All mechanical components that form a digital device are designed to work with bits

- On state – 1, Off state – 0

What’s inside?

Miniaturized wires, some microchips, and one or more circuit boards.

What’s a computer chip?

- Computer chip, microchip and chip are technical jargon for integrated circuit (IC).

- It can be used for microprocessors, memory, and support circuit.

- IC is a super-thin slice of semiconducting material packed with microscopic circuit elements,

such as wires, transistors, capacitors, logic gates and resistors.

- Semiconducting materials such as silicon and germanium are used.

- A computer chip is classified by the number of miniaturized components it contains; from small-

scale integration (SSI) of fewer than 100 components per chip to ultra large-scale integration

(ULSI) of more than 1 million components per chip.

- IC are packaged in protective carriers that vary in shape and size. Some chip carriers include DIP

(dual in-line packages & PGAs (pin-grid arrays)

How do chips fit together?

- They fit together in the system board, motherboard or main board.

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DIGITAL PROCESSING

Computers and other digital devices process data, but how do they know what to do with it?

PROGRAMS AND INSTRUCTION SETS

How do digital devices process data?

- Data is manipulated under the control of a computer program or software.

Who creates programs?

- Computer programmers create programs that control digital devices. These programs are

usually written in a high level programming language, such as C, BASIC, COBOL, or JAVA.

- Programming languages use a limited set of command words. Example – Print, If, Write, Display,

and Get. They form sentence-like statements designed as step-by-step directives for the

processor chip.

- The human readable version of a program is called source code, but it has to be converted into

digital format before the processor can use it.

How does source code get converted?

- Translation of source code into 1s and 0s can be accomplished by a compiler or an interpreter.

- Compiler – converts all statements in a program in a single batch, and resulting collection of

instructions called object code.

- Interpreter – converts and executes one statement at a time while the program is running

- Compilers and interpreters don’t simply convert the characters from course code into 0s and 1s.

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What does the conversion process produce?

- Microprocessor is hard wired to perform a limited set of activities, such as addition, subtraction,

counting and comparisons. This collection of preprogrammed activities is called an instruction

set.

- The list of codes for a microprocessor’s instruction set is called machine language. It is directly

executed by the processor’s circuitry. A set of machine language instructions for a program is

called machine code.

- Machine language instruction has two parts:

i. Op code (operation code) – it is a command word for an operation such as add,

compare, or jump.

ii. Operands – the operand of an instruction specifies the data, or the address of the data,

for the operation.

Example:

Op code 00000100 00000001 Operand = ADD 1

PROCESSOR LOGIC

What happens inside a computer chip?

- A microprocessor contains miles of microscopic circuitry and millions of miniature components

divided into different kinds of operational units, such as ALU and the Control Unit.

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ALU (Arithmetic logic Unit):

Control Unit:

What happens when a computer executes an instruction?

The computer executes a single instruction in a process called the instruction cycle (it includes 4

activities)

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What role does the control unit play?

The instructions that a computer is supposed to process for a particular program are held in the

memory. When the program begins,

the memory address of the first

instruction is placed in a part of the

microprocessor’s control unit called

an instruction pointer. The control

unit can then fetch the instruction by

copying data from that address into

its instruction register. From there,

the control unit can interpret the

instruction, gather the specified data,

or tell the ALU to begin processing.

When does ALU swing into action?

ALU is responsible for performing arithmetic and

logical operations. It uses registers to hold data

ready to be processed. When it gets the go-ahead

signal from the control unit, the ALU processes the

data and places the result in an accumulator. From

the accumulator, the data can be sent to the

memory or used for further processing.

What happens after an instruction is executed?

When the computer completes an instruction, the control unit increments the instruction pointer to the

memory address of the next instruction, and the instruction cycle begins again.