Technologies for web engg practical:

1. design a page using HTML
2. CSS(ALL TYPE)
3. JSP
4. JAVA SCRIPT
5. validation of forms
6. CONNECTIVITY with data base

Chapter 1:

• Basic structure of computer
• Introduction of computer system and its sub modules,
• Basic organization of computer and block level description of thefunctional units.
  Von newmann model,
• Introduction to buses andconnecting I/O devices to CPU and memory,
• Asynchronous and synchronous bus,
• PCI,
• SCSI.

1> Basic structure of computer
Introduction of computer system and its sub modules,

• Basic organization of computer and block level description of the
  functional units.
• Von newmann model,
• Introduction to buses andconnecting I/O devices to CPU and memory,
• Asynchronous and synchronous bus, PCI, SCSI.
• 2 >Arithmetic and Logic Unit.
  Arithmetic and logical unit hardware implementation,
• Booth’s Recoding,
• Booth’s algorithm for signed multiplication ,
• Restoring division and non restoring division algorithm,
• IEEE floating point number representation and operations.
• 3 >Central processing unit.
  CPU architecture, Register organization ,
• Instruction formats and addressing modes (Intel processor).,
• Basic instruction cycle,Instruction interpretation and sequencing,
• Control Unit operation,Hardwired control unit design methods and design examples,
  Multiplier control unit, Micro programmed control unit, basic concepts, Microinstruction sequencing and execution , Micro operations, concepts of nanoprogramming,
• Introduction to RISC andCISC architectures, design issues and examples of RISC processors.
  
  4 >Memory Organization.
• Characteristics of memory system and hierarchy, concepts of
  semiconductor memories, main memory, ROM, EPROM, RAM,
  SRAM, DRAM, SDRAM, RDRAM, , Flash memory, Stack
  Organization.
• High speed memories: Cache memory organization
  and mapping, replacement algorithms , cache coherence,
• Interleaved and associative memories ,
• Virtual memory, main memory allocation , segmentation paging,
• Secondary storage, optical memory, CDROM, DVD
• RAID,.
  5 >I/O Organization.
• Input/Output systems, Programmed I/O, Interrupt driven I/O,
• I/O channels, DMA, Peripheral Devices, U.S.B.
  6 >Multiprocessor Configurations.
• Flynn’s classifications, parallel processing concepts,
• Introduction to pipeline processing and pipeline hazards, design issues of pipeline
  architecture, Instruction pipeline, Instruction level parallelism and
  advanced issues.
  7 >SPARC
  Static and Dynamic data flow design, Fault tolerant computers,
  Interprocessor communication and synchronization, cache
  coherence, shared memory
  multiprocessor.
  8 >Systolic Architectures
  Systolic arrays and their applications, wave front arrays.

TERM WORK:
Based on above syllabus at least 10 experiments and one written test of 10 marks
to be conducted.

Text Books:
1. Miles Murdocca, “Computer Architecture and Organization”, Wiley India
2. William Stallings, “Computer Organization and Architecture: Designing and
performance”: Prentice-Hall India
3. Carl Hamacher, Zvonko Vranesic and Safwat Zaky “Computer Organization”,
McGraw Hill
Reference Books:
1. John L. Hennessy and David Patterson,” Computer Architecture A Quantitative
Approach”, Morgan Kaufman
2. Andrew S. Tanenbaum,” Structured Computer Organization”, Prentice-Hall India

WEB ML

assignment 1

Assignment 1
Sub:Web Engg
Year:Third

1. What are the different categories of web application?

2. Explain the characteristic of web application?

3. Where do requirements come from?Explain Requirement engg specifies in web engg?

4. What are the various principle of Requirement Engg?

5. Which type of requirement are important for web application?

6. How the requirement for web application is listed and documented?

7. Explain modeling specifies in web engg?

8. Explain various modeling requirements?

last date of submission:friday 18 sep 09

• STEP 1: Set Your Goals
  1. Why do you want a web site?
  The first step is to identify the reasons for creating a website and how it will fit into your overall goals.
  You need to identify your strengths and opportunities, and how they tie with your plan of creating a web site.
  You also need to look into the threats and weaknesses that can adversely affect your plans and derail your goals.
  2. How does a web site fit your overall business plan?
• What will a website do for you and your business?
• A website may be your meal ticket and the main income source; or it may be for additional income. If you have an existing business, it can be used as a marketing tool, additional revenue source, or a springboard of an entirely different business model.
• Some of the key questions you need to ask include:
  Do you want to earn money directly from your website? Is it supposed to be profitable?
  Is your website simply for marketing purposes, with no direct revenue generation objectives?
  Will your website be used solely for customer and/or technical support?
  Is your website part of a multi-channel strategy (e.g. you run a brick and mortar store or a catalog together with a website)? Or is it a single channel strategy (e.g. you are an Internet pure play business)?
  Or will your website be an information source?

7 Steps to Successful Web Site Development

STEP 1: Set Your Goals
STEP 2: Develop Your Web Site Strategy
STEP 3: Set-Up Implementation Plans
STEP 4: Start the Ball Rolling
STEP 5: Create and Launch Your Web Site
STEP 6: Promote Your Web Site and Measure Its Results
STEP 7: Maintain Your Website and Grow Your Web Business

Unified Modeling Language

The heart of object-oriented problem solving is the construction of a model. The model abstracts the essential details of the underlying problem from its usually complicated real world. Several modeling tools are wrapped under the heading of the UML™, which stands for Unified Modeling Language™. The purpose of this course is to present important highlights of the UML.
At the center of the UML are its nine kinds of modeling diagrams, which we describe here.
Use case diagrams Extra info
Class diagrams Extra info
Object diagrams
Sequence diagrams Extra info
Collaboration diagrams
Statechart diagrams Extra info
Activity diagrams
Component diagrams
Deployment diagrams

Structure of IAS

Structure of IAS

The control unit fetches 2 instruction at a time but execute only 1 instruction at a time.

Memory Buffer Register (MBR): It stores word to be written in memory or receive a word from memory.
Memory Address Register (MAR): It specifies address of memory location for data transfer
Instruction Register (IR) : It stores 8 bit opcode of the instruction getting currently executed
Instruction Buffer Register(IBR) : It holds temporarily the right instruction fetch from an instruction word in memory
Program Counter (PC): It contain address of the next instruction pair to be fetched from memory.
Accumulator(AC) & Multiplier Quotient(MQ): They hold operands and result of ALU Operations. e.g Multiplying two 40 bit numbers give 80 bit result. Higher 40 bit are stored in AC and lower 40 bit are stored in MQ.

Von Neumann

The task of entering and altering programs for the ENIAC was extremely tedious.

The programming process could be facilitated if the program could be represented in a form suitable for storing in memory alongside the data.

Then, a computer could get its instructions by reading them from memory, and a program could be set of altered by setting the values of a portion of memory.
This idea, known as the Stored-program concept, is usually attributed to the ENIAC designers, most notably the mathematician John von Neumann, who was a consultant on the ENIAC project.

In 1946, von Neumann and his colleagues began the design of a new stored-program computer, referred to as the IAS computer, at the Princeton Institute for Advanced Studies.

The IAS computer, although not completed until 1952, is the prototype of all subsequent general-purpose computers.

Figure shows the general structure of the IAS computer.

It consists of:
A main memory, which stores both data and instructions.
An arithmetic-logical unit (ALU) capable of operating on binary data.
A control unit, which interprets the instructions in memory and causes them to be executed.
Input and output (I/O) equipment operated by the control unit.

Traditional Bus Architecture

Figure shows some typical example of I/O devices that might be attached to expansion devices The traditional bus connection uses three buses local bus , system bus and expansion bus

1. Local bus connects the processor to cache memory and may support one or more local devices

2. The cache memory controller connects the cache to local bus and to the system bus.

3. System bus also connects main memory module

4. Input /output transfer to and from the main memory across the system bus do not interface with the processor activity because process accesses cache memory.

5. It is possible to connect I/O controllers directly on to the system bus. A more efficient solution is to make use of one or more expansion buses for this purpose.An expansion bus interface buffers data transfer between system bus and i/o controller on the expansion bus.

This arrangement allows the system to support a wide variety of i/o devices and at the same time insulate memory to process or traffic from i/o traffic.

Explain why multibus hierarchies are required?

If large number of devices are connected to the single shared bus , performance will suffer. There are following problems

1>Bus length is longer. Therefore propagaton time is more. This propagation dealy can affect performance. When control of the bus passes from one device to another frequently

2>The bus may become bottleneck as aggreagate data transfer demand approaches the capacity of bus. Because data rate generated by attached deviceslike graphics and video controller are growing rapidly

3>Only one master bus can operate at a time, other waits. To overcome this problem most computer system use multiple buses, generally laid out in hierarchy.

Bus design parameter
1. Type : Dedicated or multiplexed
2. Arbitration : Centralized or distributed
3. Timing ; Synchronous or Asynchronus
4. Bus width ; Address or data
5. Data Transfer Type ; R, W, Read, Modify Write, after write, block
Bus Design Parameter in details
1. Bus Type :
i) Dedicated bus:
When a bus is permanently assigned only 1 functiion , it is called dedicated bus.
E.g. separate address and data lines separate bus for memory and I/O modules
Advantages: It gives high performance and less bus contention
Disadvantages : Increased size and cost.

ii) Multiplexed bus:
When the bus is used for more than 1 funcion in different time zones it is called multiplexed bus. E.g. 8085 microprocessor outputs A7- A0 in first clock cycles on pins. AD7 – AD0.
Advantages ; few pins lines are required . less cost and save space
Disadvantages: slow in speed
2. Bus Arbitration:
Several bus master connected to a common bus may require access to the same bus at the same time. A selection mechanism called bus arbitration describes which device should be given access to the bus

i) In Centralized approach; A hardware device called bus controller or bus arbiter allocates bus. It uses one of the following type
(1) Daisy chaining
(2) Polling
(3) Multiple priority levels

ii) In Distributed Approach: each master has arbiter compared to only single in centralized approach. Equal responsibility is given to all devices to carry out arbitration process, without using a central arbiter
3. Bus Timing: In synchronous timing ,e very event is synchronized by clock whereas in asynchronous every event occurring depends on previous events of bus .

4. Bus width: It decides the number of lines to be used for address and data. More addrss lines means more memory can be accessed e.g 16 line address make 2 16 = 64 kb , 20 address line makes 220 = 1 mb memory access .
More data lines means more number of bits can be transferred at a time. Therefore speed increases.
5. Data transfer type; A bus can support various type of data transfer
1) For multiplexed bus

a) Write operation : data is outputted immediately outputting address
b) Read operation: First address is outputted then sufficient acces s time is given gto address device to output data. Now data is read from bus
c) Read , modify write; Read data transfer is followed by write data transfer at the same address. It stop other cpu to use bus.
d) Read after write; Writer transfer is followed with read transfer after some access time . it is used for checking purpose.
e) Block operation; number of data are transferred at the same address one after another e.g. saving file in secondary storage.

2) For non-multiplexed bus :
Address and data outputted at the same time on different bus. It is faster system.

Organization and Architecture
In describing computer system, a distinction is often made between computer architecture and computer organization. Although it is difficult to give precise definition for these terms, a consensus exists about the general areas covered by each.

Computer architecture refers to those attributes of a system visible to a programmer, or put another way, those attributes that have a direct impact on the logical execution of a program.

Computer organization refers to the operational units and their interconnection that realize the architecture specification.

Examples of architecture attributes include the instruction set, the number of bit to represent various data types (e.g.., numbers, and characters), I/O mechanisms, and technique for addressing memory.

Organization attributes include those hardware details transparent to the programmer, such as control signals, interfaces between the computer and peripherals, and the memory technology used.
As an example, it is an architectural design issue whether a computer will have a multiply instruction.

It is an organizational issue whether that instruction will be implemented by a special multiply unit or by a mechanism that makes repeated use of the add unit of the system. The organization decision may be bases on the anticipated frequency of use of the multiply instruction, the relative speed of the two approaches, and the cost and physical size of a special multiply unit.Historically, and still today, the distinction between architecture and organization has been an important one.

Many computer manufacturers offer a family of computer model, all with the same architecture but with differences in organization. Consequently, the different models in the family have different price and performance characteristics.

Furthermore, an architecture may survive many years, but its organization changes with changing technology.

The Five Generations of Computers

The history of computer development is often referred to in reference to the different generations of computing devices.

Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices.

First Generation - 1940-1956: Vacuum Tubes:

The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

Second Generation - 1956-1963: Transistors:

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 50s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.
Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed for the atomic energy industry.

Third Generation - 1964-1971: Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation - 1971-Present: Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer - from the central processing unit and memory to input/output controls - on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.

Fifth Generation - Present and Beyond: Artificial Intelligence

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

Computer Mother Board

Computer Mother board and its constituent components
A typical PC mother board with important components is given below:
1. Mouse & keyboard

2. USB

3. Parallel port

4. CPU Chip

5. RAM slots

6. Floppy controller

7. IDE controller

8. PCI slot

9. ISA slot

10. CMOS Battery

11. AGP slot

12. CPU slot

13. Power supply plug in
1. Mouse & keyboard: Keyboard Connectors are two types basically. All PCs have a Key board port connected directly to the motherboard. The oldest, but still quite common type, is a special DIN, and most PCs until recently retained this style connector. The AT-style keyboard connector is quickly disappearing, being replaced by the smaller mini DIN PS/2-style keyboard connector. You can use an AT-style keyboard with a PS/2-style socket (or the other way around) by using a converter. Although the AT connector is unique in PCs, the PS/2-style mini-DIN is also used in more modern PCs for the mouse. Fortunately , most PCs that use the mini-DIN for both the keyboard and mouse clearly mark each mini-DIN socket as to its correct use. Some keyboards have a USB connection, but these are fairly rare compared to the PS/2 connection keyboards.

2. USB (Universal serial bus): USB is the General-purpose connection for PC. You can find USB versions of many different devices, such as mice, keyboards, scanners, cameras, and even printers. a USB connector's distinctive rectangular shape makes it easily recognizable. USB has a number of features that makes it particularly popular on PCs. First, USB devices are hot swappable. You can insert or remove them without restarting your system.

3. Parallel port: Most printers use a special connector called a parallel port. Parallel port carry data on more than one wire, as opposed to the serial port, which uses only one wire. Parallel ports use a 25-pin female DB connector. Parallel ports are directly supported by the motherboard through a direct connection or through a dangle.

4. CPU Chip : The central processing unit, also called the microprocessor performs all the calculations that take place inside a pc. CPUs come in Variety of shapes and sizes. Modern CPUs generate a lot of heat and thus require a cooling fan or heat sink. The cooling device (such as a cooling fan) is removable, although some CPU manufactures sell the CPU with a fan permanently attached.

5. RAM slots: Random-Access Memory (RAM) stores programs and data currently being used by the CPU. RAM is measured in units called bytes. RAM has been packaged in many different ways. The most current package is called a 168-pin DIMM (Dual Inline Memory module).

6. Floppy controller: The floppy drive connects to the computer via a 34-pin ribbon cable, which in turn connects to the motherboard. A floppy controller is one that is used to control the floppy drive.

7. IDE controller: Industry standards define two common types of hard drives: EIDE and SCSI. Majority of the PCs use EIDE drives. SCSI drives show up in high end PCs such as network servers or graphical workstations. The EIDE drive connects to the hard drive via a 2-inch-wide, 40-pin ribbon cable, which in turn connects to the motherboard. IDE controller is responsible for controlling the hard drive.

8. PCI slot: Intel introduced the Peripheral component interconnect bus protocol. The PCI bus is used to connect I/O devices (such as NIC or RAID controllers) to the main logic of the computer. PCI bus has replaced the ISA bus.

9. ISA slot: (Industry Standard Architecture) It is the standard architecture of the Expansion bus. Motherboard may contain some slots to connect ISA compatible cards.

10. CMOS Battery: To provide CMOS with the power when the computer is turned off all motherboards comes with a battery. These batteries mount on the motherboard in one of three ways: the obsolete external battery, the most common onboard battery, and built-in battery.

11. AGP slot: If you have a modern motherboard, you will almost certainly notice a single connector that looks like a PCI slot, but is slightly shorter and usually brown. You also probably have a video card inserted into this slot. This is an Advanced Graphics Port (AGP) slot

12. CPU slot: To install the CPU, just slide it straight down into the slot. Special notches in the slot make it impossible to install them incorrectly. So remember if it does not go easily, it is probably not correct. Be sure to plug in the CPU fan's power.

13. Power supply plug in: The Power supply, as its name implies, provides the necessary electrical power to make the pc operate. the power supply takes standard 110-V AC power and converts into 12-Volt, 5-Volt, and 3.3-Volt DC power.

Categories of Web Application

1.DOCUMENT-CENTERED
– Informational
read-only content is provided with simple navigation and links
– Download
a user downloads information from the appropriate server (ftp-server)
– Customizable
the user customizes content to specific needs
– examples:
• static HTML-pages, „home pages“
• web radio
• simple presentations of companies/products
2.INTERACTIVE
– content of a website is dynamically generated as response to a user request
– Form-based input is the primary mechanism for communication
between client and server
– usage of HTML-forms and Common Gateway Interface (CGI)
techniques
• radio button, string input, choice lists
– examples:
• dynamic HTML pages
• public transport schedules
• search engines
3. TRANSACTION-ORIENTED
– Complex interactions
– read and write actions
– Usage of transaction management of database systems
• Efficient and consistent data management
• structured data and queries
– examples:
• Online banking
• E-shopping
• Reservation systems
4.WORKFLOW-BASED
– support business processes („workflows“) between different enterprises or private users
– An application provides a complex service to the user, e.g.
Assists the user in determining the mortgage payment
– Prerequisite: structured flow of activities
– examples:
• Business-to-Business (B2B) Integration Frameworks
• E-Government
• Patient workflows in health care systems
5. COLLABORATIVE
– support cooperation in case of unstructured flow of
activities and high degree of communication
– „groupware“
– examples:
• support of shared information- and workspaces
– Wiki, http://c2.com/cgi/wiki
– BSCW, http://bscw.gmd.de
– Chat rooms
• E-Learning platforms
6.PORTAL-ORIENTED
– the application channels the user to other Web content or
services outside the domain of the portal application
– „single point of access“
– Examples:
• Community portals
– dedicated user groups
– Customer profiles
• Enterprise portals
– Intranet, extranet –
7. UBIQUITOUS
– personalized services at every time at every location
– Multi-platform delivery (PC, PDA, mobile phone)
– Context-dependent information
– Example:
• display of today‘s menu on end-user devices while entering a
Restaurant
8. SEMANTIC WEB
– Information available on the web
• Adequate for human understanding and
• Adequate for automatic manipulation
– „knowledge management“
• Derivation of new knowledge
• re-use of knowledge
– Example:
• Web 2.0
• Social software: wiki, Flickr, del.icio.us
• Google

Web Definition

The World Wide Web (WWW, or simply Web) is an information space in which the items of interest, referred to as resources, are identified by global identifiers called Uniform Resource Identifiers (URI).

COMPUTER SOFTWARE

Software
The software is the information that the computer uses to get the job done. Software needs to be accessed before it can be used. There are many terms used for process of accessing software including running, executing, starting up, opening, and others.
Computer programs allow users to complete tasks. A program can also be referred to as an application and the two words are used interchangeably.
Examples of software programs or applications would be the Operating System (DOS, Windows 9x/Millenium/XP/Vista, O/S2, UNIX, MacOS 9.x/10.x and various others), Wordprocessor (typing letters), Spreadsheet (financial info), Database (inventory control and address book), Graphics program, Internet Browser, Email and many others.
As well any document that you create, graphic you design, sound you compose, file you make, letter you write, email you send or anything that you create on your computer is referred to as software. All software is stored in files.
Software is stored on a disk, card, tape or one of the dozens of other storage devices available.
There are millions of different pieces of software available for almost every conceivable need. Software is available commercially through stores and mail order and also available on the Internet. Software is also available through an Open Source license which allows anyone to use the Open Source software free of charge as long as the license is maintained. If you can't find the application that you need software development companies can custom design software for you.
The largest software companies offer packages of software or suites that include many of the programs that the average person or business needs. Software packages or suites contain programs that work together and share information, making it easier to combine that information in versatile ways. For example when writing a letter you can get the mailing address from an address book, include a letterhead from a graphics program and included a financial chart from a spreadsheet and combine this collection of information in the body of the letter.

Types of software:
The three basic types of software are; commercial, shareware and open source software. Some software is also released into the public domain without a license.
Commercial software comes prepackaged and is available from software stores and through the Internet.
Shareware is software developed by individual and small companies that cannot afford to market their software world wide or by a company that wants to release a demonstration version of their commercial product. You will have an evaluation period in which you can decide whether to purchase the product or not. Shareware software often is disabled in some way and has a notice attached to explain the legal requirements for using the product.
Open Source software is created by generous programmers and released into the public domain for public use. There is usually a copyright notice that must remain with the software product. Open Source software is not public domain in that the company or individual that develops the software retains ownership of the program but the software can be used freely. Many popular Open Source applications are being developed and upgraded regularly by individuals and companies that believe in the Open Source concept.
Operating Systems
All computers need some sort of Operating System (OS). The majority of modern home computers use some form of Microsoft's operating systems. The original Microsoft operating system was called DOS (Disk Operating System) though most computers use Windows. Windows comes in various versions beginning with version 3.x then 95, 98, ME and currently XP. A few computers use IBM's O/S2. Apple's Mac use their own operating system beginning with OS 1 though most modern Macs use version 8.x or 9.x. Apple's latest version is OS 10.1.x. In the past large companies and institutions would have an operating system design exclusively for them but as the commercial operating systems become more sophisticated the benefits of this practice is becoming less apparent. Some computer professionals, Internet Service Providers (ISP) and mainframe computer users use an operating system such as UNIX (or a variant such as Linux), Windows NT or 2000 (Win2k) or one of the other network or server based operating systems.
There are many smaller operating systems out there. The problem is that software is currently being developed only for the main operating systems and only the newest versions of these OS. Many older computers with unique operating systems have lots of software already developed for them but there is very little new software being developed for the older computers. The older proprietary operating systems are less likely to offer technical support than the more modern operating systems.
The operating system controls the input and output or directs the flow of information to and from the CPU. Much of this is done automatically by the system but it is possible to modify and control your system if you need to.
When you turn your computer on it first needs to load the operating system sometimes referred to a booting up. Basically the computer starts from scratch every time you turn the power on.
It checks all its components and will usually display a message if there is a problem. Loading the system is usually automatic.
Once the system is loaded the user can start the application or program that they are going to use.
Most computer users will run Microsoft Windows, Mac OS or Linux as their operating system. These OS are Graphic User Interface (GUI) which allows the user to control or run the computer using a Mouse and Icons. The user simply moves the mouse on a flat surface, rolls the trackball, or moves their hand over the touchpad to control a pointer. They then choose the option they want by pressing a button or touching the pad.
Without a GUI the user controls the computer using the keys on the keyboard. This is referred to as a Command Line Interface (CLI)
Disk and Storage
Disks and cards are used to store information. All information on computers are stored in files. The size of a file is measured in bytes.
A byte is approximately one character (letter 'a', number '1', symbol '?' etc....).
A byte is made up of 8 bits. A bit is simply an on or an off signal which passes through the computers circuitry. Every piece of software can be broken down into a series of on or off signals or it's Binary Code.
About a thousand bytes is a kilobyte (Kb).
About a million bytes is a megabyte (Mb).
About a billion bytes is a gigabyte (Gb).
About a trillion bytes is a terabyte (Tb)
* Editor's Note: I say 'about' because everything in computers must be divisible by 8 so a kilobyte is actually 1,024 bytes. The reason for this goes beyond the scope of an introductory level document but as it can cause some confusion I thought it should be mentioned.
Disk are a common way of transporting information such as bringing files home from work or sharing files. Floppy disks have become less useful as file sizes increase and Compact disks (CDs), Flash drives and Digital Video Devices (DVDs) are becoming more popular. Most software is sold on a CD. Internal Hard disks are the most common storage device.
Compact disks or CDs can store large amounts of information. One disk will store 650 Mb. One type is a CD-ROM which stand for Compact Disk Read Only Memory. Another type is a CD-RW which stands for Compact Disk - Read/Write. CD drives can copy information or burn information on to a blank CD. Common Read Only CD blanks can only be written to once though more expensive Read/Write CD's can be used over and over again.
DVD disks can store 4.5 Gb on standard disk, 8 Gb on a dual layer disk and 16 Gb on a blue-ray disk.
Digital recorders allow you to store large files, such as movies, on a single disk.
Hard disks store the majority of information on today's modern computer. Some of the first hard disk stored 10 to 40 Mb. Today the standard hard disk stores 150 Gb or more (this number is constantly increasing). Information can be stored and deleted as necessary. As files get larger the speed that hard disks can read and write become more important.
Flash drive or thumb drives range in size.
Floppy disk or diskette comes in two basic sizes; 5.25 inch and 3.5 inch. Both have a low and high density versions though 3.5 inch high density disks are the most common though many modern computers are being sold without floppy disk drives.

There are many other storage devices including tapes, Panasonic's LS120 3.5 inch diskettes, Iomega's Zip & Jazz disks, VCR tape and many others. Innovation in storage technology is advancing rapidly and some technologies become obsolete..
Information is stored in an electromagnetic form much like a cassette or video tape.
Note: Keep disks away from strong electric or magnetic fields including x-rays. Be aware of high electromagnetic areas in the room such as televisions, speakers, high tension wires, etc... Use disks only at room temperature and keep them out of direct sunlight. If possible avoid passing electromagnetic storage devices through airport x-rays. In theory information stored on a disk will last indefinitely but the physical storage device will wear out with usage and time so be sure to back up (copy) your important files to a second second storage device.

COMPUTER HARDWARE

Hardware
The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, keyboards, monitors, case and drives (hard, CD, DVD, floppy, optical, tape, etc...). Other extra parts called peripheral components or devices include mouse, printers, modems, scanners, digital cameras and cards (sound, colour, video) etc... Together they are often referred to as a personal computer.

Central Processing Unit - Though the term relates to a specific chip or the processor a CPU's performance is determined by the rest of the computer's circuitry and chips.
Currently the Pentium chip or processor, made by Intel, is the most common CPU though there are many other companies that produce processors for personal computers. Examples are the CPU made by Motorola and AMD.
With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz (MHz) the Pentium chips began at 75 MHz in the late 1990's. Speeds now exceed 3000+ MHz or 3 gigahertz (GHz) and different chip manufacturers use different measuring standards (check your local computer store for the latest speed). It depends on the circuit board that the chip is housed in, or the motherboard, as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other.
Though there were many computers using many different processors previous to this I call the 80286 processor the advent of home computers as these were the processors that made computers available for the average person. Using a processor before the 286 involved learning a proprietary system and software. Most new software are being developed for the newest and fastest processors so it can be difficult to use an older computer system.
Keyboard - The keyboard is used to type information into the computer or input information. There are many different keyboard layouts and sizes with the most common for Latin based languages being the QWERTY layout (named for the first 6 keys). The standard keyboard has 101 keys. Notebooks have embedded keys accessible by

special keys or by pressing key combinations (CTRL or Command and P for example). Ergonomically designed keyboards are designed to make typing easier. Hand held devices have various and different keyboard configurations and touch screens.
Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or CTRL, Alternate or Alt and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper.
Removable Storage and/or Disk Drives - All disks need a drive to get information off - or read - and put information on the disk - or write. Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term 'disk' and 'drive' are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files - or software - and the drive is the mechanism that runs the disk.
Digital flash drives work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use memory cards.

Mouse - Most modern computers today are run using a mouse controlled pointer. Generally if the mouse has two buttons the left one is used to select objects and text and the right one is used to access menus. If the mouse has one button (Mac for instance) it controls all the activity and a mouse with a third button can be used by specific software programs.

One type of mouse has a round ball under the bottom of the mouse that rolls and turns two wheels which control the direction of the pointer on the screen. Another type of mouse uses an optical system to track the movement of the mouse. Laptop computers use touch pads, buttons and other devices to control the pointer. Hand helds use a combination of devices to control the pointer, including touch screens.
Note: It is important to clean the mouse periodically, particularly if it becomes sluggish. A ball type mouse has a small circular panel that can be opened, allowing you to remove the ball. Lint can be removed carefully with a tooth pick or tweezers and the ball can be washed with mild detergent. A build up will accumulate on the small wheels in the mouse. Use a small instrument or finger nail to scrape it off taking care not to scratch the wheels. Track balls can be cleaned much like a mouse and touch-pad can be wiped with a clean, damp cloth. An optical mouse can accumulate material from the surface that it is in contact with which can be removed with a finger nail or small instrument.

Monitors - The monitor shows information on the screen when you type. This is called outputting information. When the computer needs more information it will display a message on the screen, usually through a dialog box. Monitors come in many types and sizes. The resolution of the monitor determines the sharpness of the screen. The resolution can be adjusted to control the screen's display..
Most desktop computers use a monitor with a cathode tube or liquid crystal display. Most notebooks use a liquid crystal display monitor.
To get the full benefit of today's software with full colour graphics and animation, computers need a color monitor with a display or graphics

card.

Printers - The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.
Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins.
Ink jet printers work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper.
Laser printers use the same technology as a photocopier using heat to transfer toner onto paper.

Modem - A modem is used to translate information transferred through telephone lines, cable or line-of-site wireless.
The term stands for modulate and demodulate which changes the signal from digital, which computers use, to analog, which telephones use and then back again. Digital modems transfer digital information directly without changing to analog.
Modems are measured by the speed that the information is transferred. The measuring tool is called the baud rate. Originally modems worked at speeds below 2400 baud but today analog speeds of 56,000 are standard. Cable, wireless or digital subscriber lines can transfer information much faster with rates of 300,000 baud and up.
Modems also use Error Correction which corrects for transmission errors by constantly checking whether the information was received properly or not and Compression which allows for faster data transfer rates. Information is transferred in packets. Each packet is checked for errors and is re-sent if there is an error.
Anyone who has used the Internet has noticed that at times the information travels at different speeds. Depending on the amount of information that is being transferred, the information will arrive at it's destination at different times. The amount of information that can travel through a line is limited. This limit is called bandwidth.
There are many more variables involved in communication technology using computers, much of which is covered in the section on the Internet.

Scanners- Scanners allow you to transfer pictures and photographs to your computer. A scanner 'scans' the image from the top to the bottom, one line at a time and transfers it to the computer as a series of bits or a bitmap. You can then take that image and use it in a paint program, send it out as a fax or print it. With optional Optical Character Recognition (OCR) software you can convert printed documents such as newspaper articles to text that can be used in your word processor. Most scanners use TWAIN software that makes the scanner accessable by other software applications.
Digital cameras allow you to take digital photographs. The images are stored on a memory chip or disk that can be transferred to your computer. Some cameras can also capture sound and video.
Case - The case houses the microchips and circuitry that run the computer. Desktop models usually sit under the monitor and tower models beside. They come in many sizes, including desktop, mini, midi, and full tower. There is usually room inside to expand or add components at a later time. By removing the cover off the case you may find plate covered, empty slots that allow you to add cards. There are various types of slots including IDE, ASI, USB, PCI and Firewire slots.
Depending on the type notebook computers may have room to expand . Most Notebooks also have connections or ports that allows expansion or connection to exterior, peripheral devices such as monitor, portable hard-drives or other devices.

Cards- Cards are components added to computers to increase their capability. When adding a peripheral device make sure that your computer has a slot of the type needed by the device.
Sound cards allow computers to produce sound like music and voice. The older sound cards were 8 bit then 16 bit then 32 bit. Though the human ear can't distinguish the fine difference between sounds produced by the more powerful sound card they allow for more complex music and music production.
Colour cards allow computers to produce colour (with a colour monitor of course). The first colour cards were 2 bit which produced 4 colours [CGA]. It was amazing what could be done with those 4 colours. Next came 4 bit allowing for 16 [EGA and VGA ] colours. Then came 16 bit allowing for 1064 colours and then 24 bit which allows for almost 17 million colours and now 32 bit and higher allow monitors to display almost a billion separate colours.
Video cards allow computers to display video and animation. Some video cards allow computers to display television as well as capture frames from video. A video card with a digital video camera allows computers users to produce live video. A high speed connection is required for effective video transmission.
Network cards allow computers to connect together to communicate with each other. Network cards have connections for cable, thin wire or wireless networks. For more information see the section on Networks.
Cables connect internal components to the Motherboard, which is a board with series of electronic path ways and connections allowing the CPU to communicate with the other components of the computer.

Memory - Memory can be very confusing but is usually one of the easiest pieces of hardware to add to your computer. It is common to confuse chip memory with disk storage. An example of the difference between memory and storage would be the difference between a table where the actual work is done (memory) and a filing cabinet where the finished product is stored (disk). To add a bit more confusion, the computer's hard disk can be used as temporary memory when the program needs more than the chips can provide.
Random Access Memory or RAM is the memory that the computer uses to temporarily store the information as it is being processed. The more information being processed the more RAM the computer needs.
One of the first home computers used 64 kilobytes of RAM memory (Commodore 64). Today's modern computers need a minimum of 64 Mb (recommended 128 Mb or more) to run Windows or OS 10 with modern software.
RAM memory chips come in many different sizes and speeds and can usually be expanded. Older computers came with 512 Kb of memory which could be expanded to a maximum of 640 Kb. In most modern computers the memory can be expanded by adding or replacing the memory chips depending on the processor you have and the type of memory your computer uses. Memory chips range in size from 1 Mb to 4 Gb. As computer technology changes the type of memory changes as well making old memory chips obsolete. Check your computer manual to find out what kind of memory your computer uses before purchasing new memory chips.