Transcript Interfacing with Computer

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
Lecture
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. It’s a
collection of wires passing electrical
signals

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 = 220 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 – the number of coulors a
pixel might take.
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
Tools
Develop
Environm
Interpreters
Compilers
OS Technical
Management
Development
Libraries
Databases
MacroProcessing
Text
Editors
Assemblers
Other
Applications
Link-Editors
Task Scheduler and Resource Alloc
Library
Debug
Routines
Loaders
Economic OS
Management
File handling
Physical I/O
Control
LEVEL
Memory Management
Process
management
Processor
Manager
Interrupts
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 – small size
network.
 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.