1. Introduction to Computing & Programming

2. Outline History of Computer Systems Computer Systems Computer Hardware
Computer Software
Programming Languages

3. History of Computer Systems

4. History of Computer Systems
1822 –The Difference Engine
by Charles Babbage - father of today’s computer
first programmable computer
mechanically calculated mathematical tables.
Hollerith Tabulating Machine
by Herman Hollerith
used punched cards to help compile the U.S. Census.
Hollerith formed his own company which later become International Business Machines (IBM).

5. First Generation Computers
1944 – MARK1
by Howard Aiken
an electromechanical computer. (the first realization of Babbage’s Analytical Engine).
1945 –1st Computer with Stored Program
by John von Neumann
1st computer which used the concept of a stored program.
The stored program used a single memory area to store both data and instructions (programs).
Prior to this computer, the instructions and data were stored in separate areas of the computer.
predecessor to modern-day computer systems.
vacuum tube

6. First Generation Computers
1946 – ENIAC (Electronic Integrator & Computer )
by John Mauchley & J. Eckert
First large scale computer
2 stories high, large enough to fill a 40ft. x 20ft. room
Could do approximately 5,000 calculations per second.
Later, Mauchley & Eckert built and marketed the UNIVAC - the first commercially available computer designed for both scientific and business applications.

7. Second Generation Computers
1958 – The IBM 7090
introduced by IBM
smaller and less expensive
more reliable than their predecessors.
Second Generation computers also used new techniques for storing data  Magnetic core memory!

8. Third Generation Computers
In the first and second generation computers, 1 tube and 1 transistor represented 1 circuit.
In third generation computers, integrated circuits (IC) is used.
1 tiny silicon chip could hold hundreds of circuits
 computers became smaller and faster.
IBM 360 (1964) - one of the first large mainframe computers using IC’s.
Packard Bell PB250
DEC PDP-8 Classic
Data General SuperNOVA

9. Fourth Generation Computers
use Very Large Integrated Scale Circuits (VLSI) on silicon chips.
many thousands circuits could be put on the new chip.
IBM first model of a fourth generation computer.
Intel developed the first microprocessor using VLSI technology in 1971.
Intel 4004

10. Fifth Generation Computers
Have begun but still in progress.
Artificial intelligence (AI) is the key characteristic.
will come close to bridging the gap between computing and thinking.
Many desired features have been developed
such as modern input/output devices such as voice, pen and pointers, which may soon replace keyboards.
AI mechanisms are currently being used in a variety of computer-based machines
washing machines, automobiles, robots, vision processing, etc.

11. Computer Systems

12. Overview 3 main classes of computers: PCs (Personal Computer)
Relatively small used by one person at a time
Workstation
Larger and more powerful than a PC
Mainframe
Still larger
Requires support staff
Shared by multiple users

13. Computer Hardware

14. Overview The hardware components of computer system:
CPU (central processing unit)
Memory (primary and secondary storage)
Input devices
Allows communication to the computer
Output devices
Allows communication to the user

15. Overview The CPU Input Output Devices Primary Secondary Storage ALU
Control
Unit
Primary
ALU
Registers
The CPU

16. The CPU
A microprocessor (chip) that executes instructions to perform processing tasks.
Component parts are:
Control Unit
Arithmetic-Logic Unit
Registers

17. The CPU Control Unit Access program instructions
Decode (interpret) instructions
Control flow of data throughout system
Data flows through paths called buses (data, address, control)

18. The CPU Arithmetic-Logic Unit Perform computations on data
Perform comparisons on data
Control
Unit
Primary
Storage
ALU
Registers
The CPU

19. The CPU Registers High speed storage areas Hold data and instructions
Control
Unit
Primary
Storage
ALU
Registers
The CPU

20. The CPU Machine Instruction Cycle Control Unit ALU Primary Storage
1. instruction fetched from primary storage
2. Decodes instruction
3. Performs calculation & comparison
ALU
4. result is stored in primary storage
Primary Storage

21. The CPU
Computer performance - measured by the number of Machine Instruction Cycles performed per second.
Factors affecting this performance include:
Clock Speed
Word Length
Bus Width
Line Width
Smaller, faster, cheaper, more powerful chips with each generation

22. Computer Memory The CPU Input Output Devices Devices Primary Storage
Control
Unit
ALU
Input
Devices
Output
Devices
Registers
Primary
Storage
Secondary
Storage

23. Computer Memory Basics
Computers are digital, represent data in bit patterns
Bit
shorthand for Binary digIT
a digit that can only consists of 2 values: 0 & 1
Byte
Each memory location has 8 bits = 1 byte
Unit
kilobyte
megabyte
gigabyte
terabyte
petabyte
exabyte
Number of bytes
210 bytes
220 bytes
230 bytes
240 bytes
250 bytes
260 bytes
Approximation
103 bytes
106 bytes
109 bytes
1012 bytes
1015 bytes
1018 bytes

24. Computer Memory Basics
Address
Number that identifies a memory location
Used to find data when needed
Some data is too large for a single byte
Most integers and real numbers are too large
Address refers to the first byte
Next few consecutive bytes can store the additional bits for larger data

25. Computer Memory Basics

26. Computer Memory Basics
Memory Access
Random Access
Usually called RAM
Computer can directly access any memory location
Sequential Access
Data is generally found by searching through other items first
More common in secondary memory

27. Primary Storage (Main Memory)
A temporary storage area that holds 3 things:
information you are working with
the application software you are using
the operating system software
memory capacity , performance of the system .

28. Primary Storage (Main Memory)
Types of Primary Storage
Registers – part of the CPU; very fast; limited capacity
Random Access Memory (RAM) – memory chips on motherboard; general storage of program instructions and data
Cache Memory – faster than RAM; provide intermediate storage between secondary storage and RAM
Read-only Memory (ROM)
– chips storing permanent
instructions needed
by computer

29. Secondary Storage Secondary memory Huge storage capacity
Stores instructions and data between sessions
A file stores data or instructions in secondary memory
Huge storage capacity
Cheaper than Primary Storage
Slower than Primary Storage
Magnetic and optical storage media

30. Secondary Storage Types of secondary storage media: Magnetic tape
Cheap, slow, sequential access: good for backup
Magnetic Disk
Floppy – slow, easily shared with other computers
Hard disk – fast, fixed in the computer
Zip drive
Memory Cards and Cartridges
Optical
CD-ROM, CD-RW, DVD, FMD-ROM
Slower than hard disks
Easily shared with other computers

31. Input Devices The CPU Input Output Devices Devices Primary Storage
Control
Unit
ALU
Input
Devices
Output
Devices
Registers
Primary
Storage
Secondary
Storage

32. Input Devices Keyboard Mouse / trackball Touch screens Scanners Webcam
Joystick
Microphone

33. Output Devices The CPU Input Output Devices Devices Primary Storage
Control
Unit
ALU
Input
Devices
Output
Devices
Registers
Primary
Storage
Secondary
Storage

34. Output Devices
Monitors
Printers
Plotters
Voice Output Devices

35. Computer Software

36. Software Fundamentals
Some basic terms…
Computer programs - sequences of instructions for the computer
Data – input to a program
Stored program concept – instructions written in programs are stored and executed by CPU when needed
Programming - process of writing (or coding) programs
Programmers - individuals who perform programming

37. Software Fundamentals
= Input +

38. Software Fundamentals
Systems Software
Instructions that manage the systems resources
Application Software
Instructions that perform specific user tasks
Computer Software
Systems
Software
Application
Software

39. Systems Software
Controls and supports the computer system’s activities
Supports application software by directing the computer’s basic functions
Facilitates program development, testing, and debugging
Is independent of any specific type of application

40. Systems Software System Control Programs System Support Programs
Control use of all system resources (hardware, software, data); operating system
System Support Programs
Specialized support capabilities
Systems Software
System
Control
Programs
Systems
Support
Programs

41. System Control Programs
Operating System (OS) - main system control program
supervises the overall operation of the computer
allocates computer resources (eg. CPU time and main memory)
allows us to communicate with the computer
responds to user requests
Common OS include:
Windows UNIX Linux DOS Macintosh OS VMS
Operating System-
supervises the overall operation of the computer, including monitoring the computer’s status and scheduling operations, which include controlling the input and output processes
allocates CPU time and main memory to programs running on the computer, and also provides an interface between the user and the hardware

42. System Support Programs
Support the operations, management, and users of a computer system
Examples:
System Utilities
Perform common tasks: sorting records, creating directories and subdirectories, restoring accidentally erased files, locating stored files, managing memory usage etc.
Performance monitors
monitor job processing
produce statistical reports on system resource usage

43. Application Software
Programs performing specific information processing activities and user functionality
Examples:
Spreadsheets
Data management
Word processing
Desktop publishing
Graphics
Multimedia
Communication
Speech-recognition
Groupware

44. Programming Languages

45. Overview
Various programming languages enable people to tell computers what to do
Foundation for developing applications
low-level
language
high-level
language

46. Programming Languages
Machine Language (first generation)
The computer’s ‘native language’
Composed of binary digits (0s, 1s) Eg
The only language that computers understand
Assembly Language (second generation)
One-to-one correspondence to machine language
Somewhat more user-friendly than machine language (mnemonic rather than binary digits)
Eg. ADD X Y Z
Assembler – program that translates an assembly language program into machine language

47. Programming Languages
Procedural Languages (third generation)
One instruction translates into many machine language instructions
Programs describe the computer’s processing step-by-step
Closer to natural language; uses common words rather than abbreviated mnemonics
Examples: C, C++, Java, Fortran, QuickBasic
Compiler - translates the entire program at once
Interpreter - translates and executes one source program statement at a time

48. Programming Languages
Nonprocedural Languages (fourth generation)
Allows the user to specify the desired result without having to specify the detailed procedures needed for achieving the result
Example: – data base query language - SQL
Can be used by non technical users
Natural Language Programming Languages (fifth generation (intelligent) languages)
Translates natural languages into a structured, machine-readable form
Are extremely complex and experimental

49. How are Programs Understood by the Computer?
The Language Translation Process
Program written in programming language (source code)
Translator program
Assembler
Compiler
Interpreter
Program written in machine language (object code)
Processed
By CPU

50. Current Programming Languages
Object-Oriented Programming Languages (OOP)
based on objects – packaging data and the instructions about what to do with that data together
Examples: Java, C++
Visual Programming Languages
Used within a graphical environment
Examples : Visual Basic and Visual C++
Popular to non technical users

51. Current Programming Languages
Hypertext Markup Language (HTML)
standard language used in World Wide Web
contains text, images, and other types of information such as data files, audio, video, and executable computer programs
Extensible Markup Language (XML)
Improved on web document functionality
Virtual Reality Modeling Language (VRML)
a file format for describing three-dimensional (3D) interactive worlds and objects
can be used with the World Wide Web

52. ~THE END ~