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قديم 30-12-2004, 08:07 AM   #1
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افتراضي الجزء الاول ((ملخص)) - M1


السلام عليكم
عندي ملخصات لمادة
T171
وحبيت انشرها لتعم الفائدة وانشاءالله راح يجي90%منها بالامتحان



مع تمنياتي لكم بالتوفيق
Module 1
Module 1: Section1:
This section, unlike most others in this module, is not based on Accidental Empires. Instead, it aims to provide you with sufficient background knowledge to understand and appreciate the rest of the material.
[list][*]
Main topics of this section:
[/list]
a- software and hardware.
b- Binary, bits and bytes.
c- Computer architecture.
d- Computer power.
e- Types of computer.
[list][*]
Explanation of the main topics:
[/list]
a- Software and Hardware:
-The computer is based on software programs , hardware components and peripherals.
Hardware:
- Hardware includes components such as microprocessor, hard disk drive, memory chip, & etc.
- Peripherals are separate hardware items that are added onto the basic computer unit like monitor, modem, printer, keyboard & etc.
Software:
A programming language is used to express the instructions which tell the computer what to do in response to a certain action.
- Software can be divided into three basic categories:
1- Operating system: these communicate with the hardware of the machine, and act as the basis on which other software programs can be run. Examples of operating systems: Dos, Windows, Unix and the Macintosh.
2- Programming Languages: these allow developers to write new software programs. Examples of programming languages: Basic, C, Assembler, Pascal, C++, Visual Basic and Java.
3- Applications: these allow you to perform activities to which the computer is suited. Examples include word processors (Ms-word), Spreadsheet (MS- excel, Lotus 123), databases (Ms- Access), graphics package (CorelDraw).


b- Binary, bits and bytes:
At its very lowest level a computer operates by turning on or off millions of tiny switches, called transistors. In computers these transistors can only be in one of two states; that is, on or off. Such devices are thus referred to as two-state devices. Another example of a two-state device might be a conventional light switch. It is either on or off, with no intermediate state. The states of 'on' and 'off' can be represented by the numbers 1 and 0.
In mathematics the term binary is used to refer to a number system which has only two digits, that is 1 and 0. The number system we use in everyday life has ten digits, 0 to 9, and is called denary.

Denary number

Binary equivalent

0

0

1

1

2

10

3

11

4

100

5

101

6

110

7

111

8

1000

9

1001

10

1010



What is binary used for?
a computer functions by manipulating 1s and 0s.
It is worth examining the difference between data and instructions. The data is the current information the computer program is working with. This might be some numbers I am adding up, or some text I am typing. It will vary from instance to instance. The instructions are what the computer does with the data.

So computers work by manipulating 1s and 0s. These are binary digits, or bits for short.
Each 8-bit unit is called a byte. A byte is the basic unit which is passed around the computer.

Analogue and digital
This is the main difference between analogue and digital: analogue signals are continuous, they can take any value within their limits, whereas digital ones can only take set values within their range. Digital signals are said to be 'discrete', which means 'separate' or 'distinct'.

What are the benefits of being digital?
Digital devices are often faster and more efficient than analogue equivalents.
There are two main reasons why digital systems are often superior: reliability and manipulation.
c- Computer architecture:
Although computers operate by manipulating 1s and 0s, this is not a very useful way for people to work. A more productive means of telling the computer what to do is required.

Assembler takes commands and converts them in to 1s and 0s, which the computer can interpret. Newer programming languages are more sophisticated, and operate at a higher level than Assembler.

The components of a computer:

The key to your computer is a chip called the microprocessor. This is its brains. Before the advent of the microprocessor, computers came mainly in the form of large mainframes.

At the core of a mainframe computer are three separate units linked together to form what is known as the central processing unit, or CPU. These three units are:

1- The arithmetic and logic unit (ALU) - this is the unit which does the actual work of the computer.
2- The control unit - this unit controls the flow of data from the computer's memory into the ALU and to other devices.
3- The memory.
A microprocessor combines the ALU and control unit on one silicon chip. In mainframes the CPU includes memory, but this is separate in microcomputers.
The CPU microprocessor is housed on a circuit board called the motherboard.
Also on the motherboard is the clock chip which acts as a metronome for the computer so that all its actions can be synchronized.
There may also be one or two ROM chips. ROM stands for Read Only Memory, which means that the data on these chips cannot be altered.
There are devices which can be used to enter data into the computer, and which it can use to output data. These are called input/output devices (usually referred to as I/O devices ) and might include a keyboard and mouse (for input) and a monitor and printer (for output).
The CPU also sends and receives data to and from the computer's memory, which is usually referred to as RAM (random access memory). This is the memory which stores all the data the computer is currently using.
The computer will also load into the RAM the programs it needs to work with this file. The contents of RAM are often lost when the computer is switched off.
The microprocessor will also have to read from and write to a permanent data storage device in the form of a hard disk drive. Other permanent storage devices include CD-ROMs.
To receive and send all of this data the microprocessor is connected to cables, which are referred to as buses.
d- Computer power:
Factors that affect computer power are the following:
1- The microprocessor chip: With more transistors available, the chip can be programmed to perform more tasks, thus increasing its complexity. Evolution: From old Intel microprocessor (80486) contains 1.2 million transistors to Intel Pentium that contains 3.1 million transistors.
2- Clock speed: Each action of the CPU can be thought of as occupying one cycle. So, the greater the number of cycles per second, the faster the computer.
3- Word size: 32-bit, 64-bit or 128-bit machine. These terms refer to the size of word that the microprocessor can manipulate.
4- RAM: It acts as the computer’s working memory. This will include various operating system commands. An increase in the size of the RAM increases the amount of data it can store at any one time. It also increases the speed of the computer because when the RAM becomes full, the computer will temporarily store data on the hard disk. So more RAM provides more speed.
e- Types of computer:
1- Mainframes: very expensive. Used by large companies, universities. They can handle the following tasks:
File maintenance: like maintaining records, booking an airline ticket, warehouse stock levels.
Simulations: to solve complex computer simulations like weather forecasting, calculating the position of astronomical bodies.
General purpose: used by universities for computing facility like store files and student information system.
2- Minicomputers: they are powerful, special-purpose computers. Examples of minicomputers like digital equipments VAX machines and IBM’s AS/400s.they are used to perform certain tasks like: Plant control, network control, Databases.
3- Workstations: they are powerful PCs. They use a special chip as RISC. They can perform the following tasks:
a- CAD/CAM.
b- Animation.
c- Simulations.
d- Multitasking programming.
4- Personal computers: they are based on microprocessors and are ideal for performing the following tasks:
a- word processor.
b- Spreadsheet.
c- Desktop publishing.
d- Games
Section 2: Intel and the microprocessor

Compare between mainframes and PCs:
Mainframes
§ Housed in special air-conditioned rooms! ® need special care
§ Carryout different tasks for several people simultaneously ® not intended for personal use
§ Operated only by specialists
§ Very expensive ® millions!
§ Sold in small numbers
· Had software based on the costumer needs
· Maintenance (machine and software) is a major task done by the manufacturing company
· The ******er-supplier relationship is long-termed
· Majority of mainframes supplied and serviced by IBM
PCs
· Cheap ® 1,000 pounds or less!
· Operated directly by anyone (specialist or non-specialist)
· Sold in huge numbers
· Utilize commonly available software
· Replaced frequently ® maintenance is very rare!
· ******er-supplier relationship is short-termed (terminated after selling the machine J)
· Many companies sell PCs: IBM, Dell, Compaq, Acer… etc.
- Automation was a target for many people long time ago
- The two factors that made it urgent:
o Second world war
o Growth of office-based work
- The Godfathers of computing are:
o Charles Babbage
o Alan Turing
o John Von Neumann
- Difference Engine
· Designed by Charles Babbage (engineer, mathematician and philosopher) in 1822
· A device to calculate navigational tables
· Ridden with errors introduced through manual calculations
· A small but incomplete working model was built
· Acted as a special purpose calculator
- Analytical Engine
· Designed also by Charles Babbage
· General purpose device
· Performs arithmetic and logic functions
· Instructions were fed by punch cards, and kept in a store( computer’s memory)
· Resembled today’s computers
· Wasn’t completed
- Turing Machine
· Designed by Alan Turing (mathematician) in 1936
· It was a general purpose mechanical device, outlined in a paper, he wrote.
· Receives basic instructions from a tape stream
· Proved that not all mathematical problems can be solved!
· It was the basis of computers
· Alan Turing did the following:
o Worked on deciphering messages composed by Enigma coding machine
o Was the founder of Artificial Intelligence (can machines think?)
- ENIAC
· Stands for: Electronic Numerical Integrator and Computer
· Designed by John Mauchly and Presper Eckert
· A project based at the University of Pennsylvania
· First large-scale computer
· Used vacuum tubes
o instead of electromechanical relays used in other computing devices
§ faster
o Perform the same task as transistors
§ Switch their states (on or off)
· Capable of performing complex calculations
o Required during the war
· Was still limited
o Had very little memory
o Reprogramming it (telling it to perform certain task) was too difficult
· To overcome its limitations ® design EDVAC, its successor
· It was still being completed
- EDVAC
· Stands for: Electronic Discrete Variable Automatic Computers)
· Designed by John Von Neumann (mathematician and intellect)
· Had a stored programmable memory
o Contained both instructions and data the computer required
· EDVAC structure resembled the modern computer architecture
· Included:
o Central arithmetic unit
o Control unit
o Memory
o Input and output units
· For this reason, modern computers are referred to as ‘Von Neumann machines’
- UNIVAC
· Designed by John Mauchly and Presper Eckert
o After splitting up the company with Von Neumann
· It was an EDVAC type computers for data processing
· Received publicity after predicting the victory of Eisenhower in the presidential election
- The microprocessor
· Computing, at its lowest level, is the control of data represented by 1s and 0s
o Turning switches on or off
· Microprocessor allows switching to occur at a very high speed
o Using millions of switches (transistors)
· Ante-microprocessors:
o Different functions done by different circuits
· Integrated circuits:
o Several functions could be performed by a single silicon ship
o Reducing the size and increasing the speed of computers
· Microprocessor is a programmable IC
o Setting the switches in a certain manner tells the microprocessor to perform certain task
- Main tasks of a microprocessor
· Read and write to computer’s memory
· Manipulate information
[list][list][list][*]
Microprocessor has its own set of instructions
[*]
Allow it to interpret the instructions it receives from the memory
[/list][/list][/list]
· Communicate with other parts of the computer
[list][list][list][*]
Coordinator role
[*]
Mainly done by the control unit
[/list][/list][/list]
- To program a microprocessor, we use:
· Assembly language:
o Different than English à difficult!
o Lots of code to do a small task
o the programmer must be very familiar with the exact working of the computer (its instruction set), in order to use it
· High level languages:
o Very close to English à easy to master
o One line of code to accomplish certain task
o No need to be aware of the computer’s instruction set
- Basic instruction set of a microprocessor consists of two main functions:
[list][list][*]
Arithmetic
[/list][/list]
o Simple arithmetic (addition, subtraction, multiplication and division)
o Complex functions are composed of the simple ones
[list][list][*]
Logic
[/list][/list]
o Computer can perform tests and carryout appropriate action
o IF, THEN and ELSE are used to perform the test
o AND and OR are used to combine many conditions in the same test
- Moore’s Law
[list][*]
Number of transistors that can be placed on the same area of a microprocessor doubles every eighteen months
[/list]
o The power doubles every eighteen months
o The price is fixed
- Implications of Moore’s Law
[list][*]
the computers will become increasingly powerful
[*]
microprocessors become cheaper
[/list]
o Cheap microprocessors can be placed in many products with pre-programmed functions
o These are called micro controllers
o Appliances having intelligence
§ Washing machines
§ Video cassettes
§ Recorders
§ Etc
[list][*]
Storage capacity falls in price by 20% per year
[/list][list][list][*]
5 gigabytes this year à 6 gigabytes next year with the same price
[*]
Cheap storage and effective processing of information
[/list][/list][list][*]
Constant change for the computer user
[/list][list][list][*]
No need to upgrade or maintain à by a new one!
[*]
Better features, more powerful, with the same price (or maybe less!)
[/list][/list]
- Intel Company: Established by Bob Noyce and Gorden Moore
[list][*]
It was one of the first technological start-up companies, which set the trend for the current computer industry
[*]
Initially produced SRAM and DRAM
[/list][list][list][*]
Forms of computer memory
[/list][/list]
- The Microprocessor à The idea:
[list][list][*]
Raised from the calculator design
[*]
Instead of having many different circuits, each with hard-wired function, one general purpose circuit could be used to perform all the functions… by programming!
[/list][/list]
w Changing the set of instructions to perform different task
· It is simply a programmable IC
· Examples: 4004, 8008, 8080, 80286, 80386, 80486, Pentium… etc

Section 3: The start of the PC industry
- Microprocessor found its applications in small computers, not in mainframes!
- Small companies started up by:
n Manufacturing PCs
n Providing software for them
- Based on two factors:
n A brilliant technical achievement
n Forceful management and marketing drive
- Microsoft
w Established by: Bill Gates & Paul Allen
w Their first big achievement was developing BASIC for the Altair computer
n Transported from mainframes to PCs
- Microsoft Trends
w Never reinvent the wheel!
n They took existing product and adapted it to make it a Microsoft product.
n Windows interface was borrowed from Mac.
w PCs have replaced mainframes in many companies and fields
n Specially in networking applications (client-server)
w Microsoft established a standard for the industry as a whole
n ‘We set the standard’ à their motto
w Operating systems
w Programming languages
n Other companied follow their standard
w Mixing the technology with business
n Few people can do it!
n Gates and Allen were two role models for successful specialists, technologically and business-wise
w Bill Gates fought software piracy, when pirate copies of BASIC were passed around!
w Microsoft and Bill Gates history is the same as the PC’s history, They are synonymous!
w Microsoft mission was: “A computer on every desk in every house, running Microsoft software”
n First part is technological
n Second part is business-oriented! (the most crucial)
- Operating Systems
w It is the software that makes the computer alive
w It has three main tasks:
n Manages the computer resources
l Looks after the computer
l Manages the use of CPU, memory, disk drives and input/output functions
n Interacts with the user
l Translates the user commands to be comprehensible for the computer hardware
n Runs applications
l Provides means of executing them
l Provides the programs with tools and services
w Commands to fetch data from the hard disk
w Commands to send data to the printer
- Bootstrapping
w The computer needs to load its own operating system when it starts up
n Reads a small program in ROM
n Called the boot or bootstrap program
n Loads the essential features of the operating system
n The OS in stored either in the hard disk or floppy disk
l The computer looks for it initially in the floppy disk drive
l Computer can be restarted if the hard disk has been corrupted
l Complains if there was a non-system disk in the floppy disk drive when starting up

- CP/M
w Stands for “Control Program for Microcomputers”
w Invented by Gary Kildall
w The first operating system for PC
w Text based
n The user had to learn a series of commands to perform actions, ex: to change a directory or list its contents
w The predecessor to DOS
- DOS
w Also text based
w Using the prompt ‘C:\’
w Set of commands to achieve desired functions, examples:
n C:\ cd docs --> change directory
n C:\ dir --> list content of directory
n C:\ del letter.doc --> copy file from a location to another
n C:\ copy letter.doc c:docs --> delete file
- Text based operating systems were difficult to use for most of people
n More friendly interface was required to be used by the general public
à The birth of graphical user interface OS
- Graphical Operating Systems :Use icons and menus, interacted with via a pointing device (like a mouse)
w Have two main advantages:
n Ease of use
l Easy and quick to learn
l No need to memorize a big bunch of commands
n Consistency it provides
l Providing common set of tools (menus, icons, lists, text boxes… etc)
l The look and operation of many applications can be made uniform --> be learnt quickly
w Disadvantages:
n Hides lots of operations --> weaken the user control over the computer
l The more the software does --> the more it hides!
n Slower than the textual command-based
- Graphical interface OS are now dominant in the microcomputer industry
n Window
n Macintosh
- BIOS
w CP/M was constructed of three modules, performed different functions
w The most important one is BIOS (Basic Input/Output System)
n Interacts with various input and output devices of the computer that is using CP/M
l Through it, the computer will read a character typed on the keyboard or send text to the printer.
w Only the I/O devices may vary from a computer to another
w Only the BIOS need to be changed from a computer to the other, while keeping the rest of operating system modules unchanged
à CP/M was portable (run on different computers by changing the BIOS only)
w This modular design was used in the following OS
w Code reusing becomes so important with the increasing complexity of software
n Using the same module in different programs eases the production of programs and saves time and effort
- Apple
w Established by Steve Jobs and Steve Wozniak
n Steve Jobs --> business-mined individual
n Steve Wozniak --> the technological party
w Started in Steve Job’s parents’ garage!
w Apple I à text based
w Apple II à featured colour graphics
- Characteristics of new PC companies
w Very informal culture
n Wear what you like
n Work when you like
n Do what you like (play music, dance, … etc)
w Young talented employees
n Hobbyists
n From diverse backgrounds (archaeologists, psychologists… etc)
w Intellectual creativity
n Employees are encouraged to work on projects they found interesting
n They are creative and so smart (gurus)
w Incredible success, incredibly quick
n Becoming a millionaire ‘overnight’!


Section 4: Xerox PARC
- Xerox had made a lot of money from photocopiers by the start of 1970
- Later, Xerox re******ed the development of computers at the Palo Alto Re****** Center (PARC)
- Computing ideas invented at PARC:
n GUI (Graphical User Interface)
n Ethernet (networking protocol)
n Object oriented programming (programming paradigm)
n The laser printer
- WYSIWYG system: It mimics the reality!
- To allow WYSIWYG, a graphical user interface had to replace the text-based one
- GUI allows you to:
n Move the curser
n Highlight text
n Open several docs at the same time
n Draw graphics
n Click buttons and open menus
n etc
n Represents images inside the computer
n Images needed to be converted to machine language (0s and 1s)
à bit mapping technology
n Divides the screen (any image) to thousands of tiny picture elements (pixels), and specify a value for each
n In case of b/w monitors:
n Pixel represented by a single bit
n 1 à black, 0 à white
n The dominant colour wins!
n In case of coloured monitors:
n More bits are used per pixel
n Every pixel represents a colour
n Resolution of a display à how clear an image is represented in your computer
n Display sizes:
n 640 x 480
n 800 x 600
n 1024 x 768
n The larger the size, the more pixels are available, the higher resolution your display has --> better!
- PARC Alto
n It was the first machine to use GUI
n Never marketed
n It was seen by a team of people from Apple in 1979 à GUI OS started
- Benefit of computer Networks
n Sharing resources:
n Share hardware (printers) and software (word processing package)
n Save money and installation efforts
n Communication:
n To ease contacting over large geographical distances
n Using emails
n File access:
n Mainframes or minicomputers store data files
n Other computers access them
n Example: banking system
- Types of networks
n Based on the network shape (physical structure) Topology
n Star topology
n Nodes are arranged in a star shape surrounding a central or a hub computer
n Nodes can be PCs, printers, mainframes… etc
n The hub:
n Controls the network
n Often be a mainframe or minicomputer
n Example: ATMs
n Each ATM is a node
n The hub contains bank balances, PIN codes …etc
n Ring topology
n Chain of nodes linked in a circular fashion
n The fastest network topology
n All the nodes have equal power and precedence
n Example: connecting large-scale computers (mainframes, minicomputers … etc)
n Bus topology
n A single line connected to each node (like stops on a bus route)
n Example: PCs, a minicomputer and several printers in a department can use a bus network
n Disadvantage: traffic collisions!
n Based on the network size
n WAN (Wide Area Network)
n Covers a large geographical area
n Each node maybe located in a different town
n A mainframe or minicomputer usually be involved
n Example: a multi-branch banking network
n LAN (Local Area Network)
n Covers a small area (a building or an institution)
n examples: a university uses LAN, also an individual bank branch
n Interconnected LANs and WANs form a network of networks àThe Internet
n MAN (Metropolitan Area Network)
n Larger than LAN and smaller than WAN
n Used in a certain suburb or city
n Example: a company with several branches, in the same city, uses a MAN
- A network protocol must:
n Allow smooth flow of traffic (avoid collisions)
n Prevent unnecessary blockage or delays
n Ensure the intelligibility of data to all the nodes
n Ensure the validity of data (not corrupted)
- Ethernet
n Network protocol for LANs
n Operates on the bus topology
n Developed by Bob Metcalfe at Xerox PARC
n It is reliable, speedy and cheap
- How does the Ethernet Work?
n It uses one high-speed cable, which all the nodes are connected to
n Only one node can use the line at any one time à to avoid collision
n If two nodes send messages at the same time, collision will occur and the messages will be mixed and garbled
n Each node must listen to the line, to see if it is in use
n If not à send
n If in use à wait until free
n If, by chance, two or more transmissions occur à collision!
n The network detects the collision
n Sends a message to all users indicating that the network is jammed
n Each node stops transmitting
n After a random period of time, each node starts transmitting again
n Because of the random time, another collision will be rare!
n The node that transmitted first may occupy the network
n The second one should wait… and so on
- Management in the IT industry
n Inventing a software is a difficult task, it requires:
n Creativity
The programmer should be free, and work under no pressure or strict rules
n Structured engineering principles
Programmers should be monitored, coordinated and managed to ensure that everything is tiptop
n IT management can be:
n Vertical
Structured engineering principles are more important
Conventional
Hierarchical
A person at the top level(boss), coordinates the company by communicating with the next level down
Repeatedly done
A two-way communication
Lower level employees communicate directly with the level above them
As you go up the hierarchy:
Amount of power
Responsibilities
Financial rewords à Increases!
As you go down the hierarchy àAmount of decisions increases
خوخة غير متصل   رد مع اقتباس
قديم 30-12-2004, 02:35 PM   #2
بهاء الدين بهاء الدين غير متصل
طالب فضي

 









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الله يعطيك العافيه خوخه
يااااااااااااااا احلى خوخه!!!!!!!!!!!!!!!!!!!
بهاء الدين غير متصل   رد مع اقتباس
قديم 30-12-2004, 03:53 PM   #3
~*~FnOoN~*~ ~*~FnOoN~*~ غير متصل
طالب فضي
 
الصورة الرمزية ~*~FnOoN~*~

 











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تسلمي أخت خوخه و يعطيكي ألف عافية...و جزاكي الله ألف خير.....

أختك في الله..


منى
~*~FnOoN~*~ غير متصل   رد مع اقتباس
قديم 30-12-2004, 11:01 PM   #4
ambitious_student ambitious_student غير متصل
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جزاكِ الله خير أختي " خوخة"

ambitious_student غير متصل   رد مع اقتباس
قديم 31-12-2004, 04:11 AM   #5
خوخة خوخة غير متصل
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الصورة الرمزية خوخة

 










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الله يعافيكم وانشاءالله تعم الاستفادة


ملاحظة: تكملة التلخيص في موضوع ثاني بعنوان الجزء الثاني
خوخة غير متصل   رد مع اقتباس
قديم 03-01-2005, 06:04 PM   #6
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افتراضي الرد على : Module1 summaryالجزء الأول من الملخص


خوخه .. شكرا لك ..
سلمت يداك
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قديم 30-01-2005, 04:16 AM   #7
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thaaaaanx aloooooooooooot
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ولا تعبر باي شكل من الاشكال عن وجهة نظر منتديات AOUA
تصميم وتطوير : التكنولوجيا الماسية