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Introduction to Computing

<<< Previous REVIEW & WRAP-UP of Introduction to Computing
 
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Introduction to Computing ­ CS101
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LESSON 45
REVIEW & WRAP-UP
During the last Lesson we discussed Programming Methodology
·
We looked at a few effective programming practices that result in the development of correct
programs with minimum effort
·
We also became familiar with testing & debugging
readable
program?
A program that is easy to read &
understand, and therefore, easy to
maintain & enhance
Design Guidelines
·
Break your code down into short and simple functions (e.g. take the 3 swap statements out from the
last example and put them into a function of their own)
·
Do not use global variables
Coding Guidelines
·
Indent blocks of code (2 to 5 spaces)
·
Always use semicolons to end statements
·
Identifiers:
­
Use the camelBack scheme
­
Make them descriptive but concise
­
Variables: nouns
­
Functions: verbs
·
Comment liberally
Guidelines for Developing Short Programs
·
Read, understand the
·
problem
Write the code on a piece of
·
paper
Do you have all the
·
required data?
Hand-check it
No: Get it
·
Type it in
Else assume it. State it
·
Run & check it on test cases
explicitly
·
Errors? fix & redo 9
·
Do the design
·
Done!
·
Write test cases
Design & Code Reviews
·
Probably the most efficient way of improving the a program
·
Being humans, at time we see what is supposed to be there instead of what is actually there
·
Another pair of eyeballs may not have the same problem, especially if they are were not involved
in building the design or code
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Introduction to Computing ­ CS101
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Testing & Debugging
·
Testing: The tasks performed to determine the existence of defects
·
Debugging: The tasks performed to detect the exact location of defects
·
Defects are also called bugs or errors
·
Let us now look at one of their classifications
Types of Errors
·
Syntax errors
·
Semantic errors
·
Run-time errors
Today's Goal:
(Review & Wrap-Up)
·
To review some of the interesting ideas that we discussed over the last 44 lectures
·
Please note that this lectures is not a comprehensive review, just a sampler!
Course Objectives
1.
To build an appreciation for the fundamental concepts in
computing
To achieve a beginners proficiency in Web page development
2.
To become familiar with popular PC productivity software
3.
Progression of Computer Technology
1.
Mechanical computing
2.
Electro-mechanical
3.
Vacuum tube
4.
Transistor
(the current state-of the-art)
5.
Quantum computing
Quantum Computers
·
Quantum computers may one day be millions of times more efficient than the current state-of-the-
art computers ...
·
as their quantum mechanical nature will allow them to examine all possible answers to a question,
simultaneously
The World Wide Web
·
A huge resource of info
·
Logically unified, but physically distributed
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Introduction to Computing ­ CS101
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It is unlike any previous human invention:
­
It is a world-wide resource, important to all and shared by all of the people in the world
The Semantic Web
Whereas, today's Web's content is designed for humans to read; the Semantic Web's content will be
designed for computers to understand meaningfully
Internet: Network of Networks
·
A large number of networks, interconnected physically
·
Capable of communicating and sharing data with each other
·
From the user's point view, Internet ­ a collection of interconnected networks ­ looks like a single,
unified network
Language of the Internet: TCP/IP
Transmission Control Protocol/Internet Protocol
·
TCP breaks down the message to be sent over the Internet into packets
·
IP routes these packets through the Internet to get them to their destination
·
When the packets reach the destination computer, TCP reassembles them into the original message
Instant Messaging
·
eMail: Slow response times
·
eMail: No way of knowing if the person we are sending eMail to is there to read it
·
eMail: The process of having a conversation through eMail by exchanging several short messages
is too cumbersome
·
Instant messaging (IM) solves these problems
On-Chip Cache Memory
·
That small amount of memory located on the same chip as the uP
·
The uP stores a copy of frequently used data and instructions in its cache memory
·
When the uP desires to look at a piece of data, it checks in the cache first. If it is not there, only
then the uP gets it from the main memory
·
Its proximity to the uP makes access times short
Ways of Enhancing A uP
·
Increase the clock frequency
·
Increase the word-width
·
Add more functional units (e.g. ALU's, FPU's, Vector/SIMD units, etc.)
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Introduction to Computing ­ CS101
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Hardware
Operating System
Device Driver
Utilit
Language
Scientific
Business
Productivit
Entertainment
y
Translator
Apps.
Apps.
y
Apps.
Apps.
System software
Application software
The Role of An OS
·
Manages the HW and SW resources of the computer system, often invisibly. These include the
processor, memory, disk drives, etc.
·
Provides a simple, consistent way for applications to interact with the HW without having to know
all the details of the HW
Who Owns Software?
·
Generally, although a piece of SW that is being used by millions, it is not owned by any of them!
·
When we buy a SW package, we do not really buy it ­ we just buy a license that allows us to use it,
the ownership stays with the maker
4th-generation languages
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Machine languages
Interpreters:
Immediate response, but execute code slowly
Compilers: Compiling takes time, but super-fast execution
High-level languages
Assembly languages
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Concept &
Feasibility
Test
User Requirements
Developer Specs
Test
Planning
Test
Design
Test
Test
Implementatio
n
Integration
Testing
Acceptance
Opr. &
Test
Maintenance
Retirement
Algorithm
1st Definition:
Sequence of steps that is taken
to solve a problem
Better Definition:
A precise sequence of a limited
number of unambiguous, executable
steps that terminates in
the form of a solution
Pseudo Code
·
Quite suitable for SW development as it is closer in form to real code
·
One can write the pseudo code, then use it as a starting point or outline for writing real code
·
Many developers write the pseudo code first and then incrementally convert each line into real
code
Heuristic
Common sense Lesson drawn from experience
(Artificial) Intelligent Systems
SW programs or SW/HW systems designed to perform complex tasks employing strategies that mimic
some aspect of human thought
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Introduction to Computing ­ CS101
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Not a Suitable Hammer for All Nails!
if the nature of computations required in a task is not well understood
or there are too many exceptions to the
rules
or known algorithms are too complex or  inefficient
then artificial intelligent systems have the potential of offering an acceptable solution
Database
·
A collection of data organized in such a fashion that the computer can quickly search for a desired
data item
·
All data items in it are generally related to each other and share a single domain
Relational Databases
·
Databases consisting of two or more related tables are called relational databases
·
A relational database stores all its data inside tables, and nowhere else
·
All operations on data are done on those tables or those that are generated by table operations
Future Trends:
On-Demand Computing Power
·
Almost infinite "computing power" supply
·
Reliable, maintenance-free, just like the electricity, telephone, or water-supply service
·
No capital expenditure; you pay for only what you use!
·
Same will be true for storage
Future Trends: Immortal Minds
·
Some day it will be possible to load all the lectures, papers, books and SW produced by an expert
into an intelligent system
·
After that system processes, indexes and restructures the info in those artifacts, it will be possible
to have a conversation in plain English (or some other language) with that system
Distances Are Contracting!
Distances Are Increasing!
·
Because of the ever-decreasing costs of verbal, text, video communications, it is becoming easier to
stay in touch of anyone, regardless of their physical location
·
Solitude is the order of the day as many children & adults spend their free time surfing, chatting,
playing computer games, instead of spending it on interacting with friends or family
Computers may Become too Powerful!
·
Computers keep on becoming more and more powerful, gaining more and more autonomy
·
They are being equipped with fail-safe and self-healing technologies
·
Are we heading towards a future where the role of the masters and the slaves will be reversed?
Why JavaScript?
·
HTML is great for static Web pages; however, supports only rudimentary interactivity through
forms and hyperlinks
·
JavaScript can be used (along with HTML) to develop interactive content for the Web
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Some of things that JavaScript cannot do!
·
The following file ops. on the client computer:
­Read
-- Modify
­Rename
-- Delete
­Create
·
Create graphics (although, it does have the ability to format pages through HTML - including the
placement of graphics)
·
Any network programming bar one function: the ability to download a file to the browser specified
through an arbitrary URL
Advantages of Client-Side Scripting
·
Reduced server load as it does not have to send messages to the user's browser about missing or
incorrect data
·
Reduced network traffic as the form's data is sent only once instead of many to's and fro's
A collection of
properties &
methods
All objects have the
"name" property: it holds
the name of the object
(collection)
prop 1
method 2
prop 2
prop 5
prop 3
method 1
method 3
prop 4
Object: A named collection of properties (data, state) & methods (instructions, behavior)
Functions
·
A named group of statements that is put together once and then used (by reference) repeatedly on a
Web page
·
Code becomes easier to read, understand and maintain
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Local and Global Variables
Local or Function-level Variable
Effective only in the function in which they are declared
Global Variables
Visible everywhere on the Web page
Image Preloading
·
The Image object can be used to download an image into the cache before it is actually needed for
display
·
This technique can be used to create smooth animations or to display one of several images based
on the requirement
Productivity SW
·
The lectures and assignments were designed to give a brief introduction, and no more
·
All we desired was for you to become able to open the package and perform some trivial tasks
·
With time, you will find more and more use for these packages, and gradually develop an expertise
that later will become very useful in your career
Course Objectives
1.
To build an appreciation for the fundamental concepts in computing
2.
To achieve a beginners proficiency in Web page development
3.
To become familiar with popular PC productivity software
·
How successful were we in helping you achieve those objectives?
·
Please do let us know so that we can modify the future offerings of this course accordingly. I will
be most grateful
·
I have enjoyed doing this course with you very much
·
Hope it was enjoyable & useful for you as well
·
I thank you for your attention and especially for your eMail & discussion board messages
·
A good number of those messages were quite informative and I thank you for sharing that info with
me
·
Until the next time when we meet ...
********************THE END*******************
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Table of Contents:
  1. INTRODUCTION
  2. EVOLUTION OF COMPUTING
  3. World Wide Web, Web’s structure, genesis, its evolution
  4. Types of Computers, Components, Parts of Computers
  5. List of Parts of Computers
  6. Develop your Personal Web Page: HTML
  7. Microprocessor, Bus interface unit, Data & instruction cache memory, ALU
  8. Number systems, binary numbers, NOT, AND, OR and XOR logic operations
  9. structure of HTML tags, types of lists in web development
  10. COMPUTER SOFTWARE: Operating Systems, Device Drivers, Trialware
  11. Operating System: functions, components, types of operating systems
  12. Forms on Web pages, Components of Forms, building interactive Forms
  13. APPLICATION SOFTWARE: Scientific, engineering, graphics, Business, Productivity, Entertainment, Educational Software
  14. WORD PROCESSING: Common functions of word processors, desktop publishing
  15. Interactivity to Forms, JavaScript, server-side scripts
  16. ALGORITHMS
  17. ALGORITHMS: Pseudo code, Flowcharts
  18. JavaScript and client-side scripting, objects in JavaScript
  19. Low, High-Level, interpreted, compiled, structured & object-oriented programming languages
  20. Software Design and Development Methodologies
  21. DATA TYPES & OPERATORS
  22. SPREADSHEETS
  23. FLOW CONTROL & LOOPS
  24. DESIGN HEURISTICS. Rule of thumb learned through trial & error
  25. WEB DESIGN FOR USABILITY
  26. ARRAYS
  27. COMPUTER NETWORKS: types of networks, networking topologies and protocols
  28. THE INTERNET
  29. Variables: Local and Global Variables
  30. Internet Services: FTP, Telnet, Web, eMail, Instant messaging, VoIP
  31. DEVELOPING PRESENTATIONS: Effective Multimedia Presentations
  32. Event Handlers
  33. GRAPHICS & ANIMATION
  34. INTELLIGENT SYSTEMS: techniques for designing Artificial Intelligent Systems
  35. Mathematical Functions in JavaScript
  36. DATA MANAGEMENT
  37. DATABASE SOFTWARE: Data Security, Data Integrity, Integrity, Accessibility, DBMS
  38. String Manipulations:
  39. CYBER CRIME
  40. Social Implications of Computing
  41. IMAGES & ANIMATION
  42. THE COMPUTING PROFESSION
  43. THE FUTURE OF COMPUTING
  44. PROGRAMMING METHODOLOGY
  45. REVIEW & WRAP-UP of Introduction to Computing