Human-Computer Interface

Human-Computer Interface

Course Syllabus

 Concepts of Information technology  Using the computer and managing files  The wide Internet  Word Processing  Spreadsheets  Databases  Presentations and multimedia  Information and communication

Content

 Administrative Tasks & Organization  General concepts  Hardware and Software  Information Networks  The use of IT in everyday life  Security  Copyright and the Law

Administrative Tasks - Organization

 Purpose: – Facultative not mandatory material – To become familiar with computer technology – Learn to use Office productivity tools  Laboratory – each two weeks  Exam – “Hands on work” – Written test Course Labs Exa m Practic e Try

Concepts of Information technology

 What IT means ?

– Information Technology = everything linked to using computers, computer technology. Includes the hardware, software and telecommunications.

 What is Hardware ?

– Electronic devices that compose a computer.

 What is Software ?

– Computer programs collections – Instructions that will be executed by a computer and will have affect the hardware

Concepts of Information technology

 Firmware – It’s a “

hardware

” software component  Computers – Machines that process data and information and return results to the users.

 Computer Science – Special term that refers mostly the theoretical and academic dimensions of using computers.

Computer Types

They all have a common basic structure.

 Mainframes  Personal computers  Network computers and terminals  Laptops, personal assistants.

They differ in: purpose, speed, cost, storage capacity, processing power and typical users

The main components of a computer

 CPU  Memory  Storage devices  Input devices  Output devices  Peripheral devices

The Von Neumann Machines

The Central Processing Unit

 CPU = Central Processing Unit – Logical Control Unit  Controls the machines cycles and execution units:

fetch, decode, execute, store.

– Arithmetic Logic Unit – execution unit  Does all the calculus  CPU = Processor +Registers  Stores and retrieves data from internal memory

The System BUS

 The

system bus

connects the various components of a VNA machine.

signals It’s a collection of wires passing electrical  8086 has 3 bus types: – Address bus – Data bus – gives the processor bus – Control bus

CPU Speed

 CPU uses the Internal Clock to handle synchronization  System Clock = electrical signal on the control bus which alternates between zero and one at a periodic rate

CPU Speed



The system clock frequency

= speed at which the system clock alternates between 0 and 1.

 CPU Speed = the number of clock cycles occurring each second.



Ex: Pentium III ~ 1000 cycles/sec = 1000 Hertz = 1 GHz

Memory

 A device that can store information in any format understood by the CPU.

Memory Classifications

  Localization – –

External

(to CPU) – hard-disk, floppy, external devices

Internal

– memory chips.

Persistence – Volatile – Non-volatile  Operations – ROM – Read Only Memory – non volatile – RAM – Random Access Memory

Measuring Memory

 Allocation units: bits, bytes, Kbytes, Mbytes, Gbytes,Tbytes.

 1 bit represents values

0

and

1.

 1 bytes = 8 bits = 1 character  1 KB = 1024 bytes  1 MB = 1024 KB = 2 20 bytes  1 GB = 1024 MB

Example - Measuring memory

 A book with 500 pages, ~ 40 lines/page with ~ 40 characters/line gives

500x40x40 = 800.000 characters

 800.000 characters = 800.000 bytes = ~ 781 KB =~ 0.76 MB  0.76 MB holds easily on a simple floppy disk.

Input Devices

 Help sending data to the CPU. They convert data from a human understandable format to a format that the CPU understands.

 Examples: – Mouse / Keyboard – Scanner – Trackball/touchpad – Joystick / light pen – Digital camera / microphone

Output Devices

 Display processing results. They transform CPU language data into human understandable data.

 Examples: – Monitors / Screens – Printers / plotters.

– speakers

Graphical Output Devices

Monitor – used mostly to display information to the user.



Size

– diagonal measured (ex. 17 inch) 

Resolution

– measure of the display clarity – measured in pixels.

 

Refresh rate

– number of screen redraws/sec – flickering for small values.

Color Resolution

pixel might take.

– the number of coulors a

Low Resolution image

High resolution image

Input/Output Devices

 They transfer data into both directions – from the human format to the CPU and vice versa.

 Examples: – Touch Screen – Virtual Reality Head Helmets – Virtual reality gloves.

Storage devices

 Provide data storage space – mainly for long term usage.

 They differ on terms of cost, capacity and speed.

 Types: – Floppy, zip disk (1.4 MB; 512 MB) – Data cartdrige/tape (400 MB – 200 GB) – CDROM – CD-R (Write once/read-only), CD-RW, DVD-R and DVD-RW. (650 MB – 4.3 or 9 GB) – Internal/External hard disk (20 GB – 1TB)

Software

 Programs collection running on a computer.

 Types: – Application software – Operating system software

Application software

 Programs created in order to solve different user problems or handle user requirements.

 They are used by other programs or directly by the human users.

 Examples: – Text editors, games, database applications, Web-browsers, communication tools, etc

Operating system software



Operating System

– software that controls the computer hardware and implements services.

 OS – is automatically launched when the computer is booted.

 They handle and control all other programs on a computer.

OS Structure

User User interface Services LEVEL Control LEVEL

Develop Environm Compilers OS Technical Management Tools Interpreters Development Libraries Macro- Processing Assemblers Databases Text Editors Link-Editors Other Applications Debug Routines Loaders Library Economic OS Management Task Scheduler and Resource Alloc File handling Physical I/O Memory Management Interrupts Process management Processor Manager

Hardware HUMAN operator

Operating Systems

 Interaction with operating systems: – Command language – Unix, MS-DOS – Graphical User Interface – Windows  Operating systems examples: – MS-DOS, MacOS, Windows (NT/2000, XP, 2003), Unix, Linux

Information Network

   

Computer Network

= autonomous and interconnected computer systems collection.

LAN – Local Area Network

network.

– small size

WAN – Wide Area Network

– large/very large heterogeneous computer network.

MAN – Metropolitan Area Network

medium sized computer network (building/region) –

Computer Networks advantages

 Resource sharing.

– Printers – Processing power (distributed systems) – File sharing.

 Communication support and media – email, ftp , WWW, etc.

Intranet/Internet



Intranet

- a private network that is contained within an organisation. It may consist of many interlinked local area networks and also use leased lines in the Wide Area Network.



Extranet

- a private network, that shares part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses from outside

Internet



Internet

– a large scale, global computer network. It is conceived to interconnect any type of computer system from mainframe to PC.

 Advantages: –

Any two computers can communicate irrelevant of their position.

– –

File and message exchange WWW browsing.