Information Technology Basics

Information Technology Basics
Chapter 1 Information Technology Basics

Computer Systems A computer system consists of hardware and software components. Hardware is the physical equipment such as the case, floppy disk drives, keyboard, monitor, cables, speakers, and printers. The term software describes the programs that are used to operate the computer system. Computer software, also called programs, instructs the computer on how to operate. These operations may include identifying, accessing, and processing information.

Computer Software There are two types of software: operating systems and applications. Application software accepts input from the user and then manipulates it to achieve a result, known as the output. Examples of applications include word processors, database programs, spreadsheets, web browsers, web development tools, and graphic design tools. An Operating System (OS) is a program that manages all the other programs in a computer. It also provides the operating environment with the applications that are used to access resources on the computer.

Operating Systems Examples of Operating Systems
The Disk Operating System (DOS) Windows 98 Windows 2000 Windows NT Linux Mac OS X DEC VMS IBM OS/400

Computer Types Mainframes - The mainframe model consists of centralized computers, usually housed in secure climate controlled computer rooms. End users interface with the computers via "dumb terminals." These dumb terminals are low cost devices that usually consist of a monitor, keyboard, and a communication port to talk to the mainframe.

Mainframe Computers There are several advantages of mainframes:
Scalability, the ability to add more users as the need arises Centralized management Centralized backup Low cost desktop devices (dumb terminals) High level of security

Mainframe Computers There are several disadvantages of mainframes:
Character based applications Lack of vendor operating system standards and interoperability in multi-vendor environments Expensive, with a high cost for set up, maintenance, and initial equipment Potential single point of failure (non-fault tolerant configurations) Timesharing systems, which means that there is a potential for a bottleneck

Personal Computers There are several advantages of PC computing:
Standardized hardware Standardized, highly interoperable operating systems GUI interface Low cost devices (when compared to mainframes), low cost of entry Distributed computing User flexibility High productivity applications

Personal Computers There are several disadvantages of PC computing:
Desktop computers cost, on average, five times as much as dumb terminals, according to some industry estimates No centralized backup No centralized management Security risks can be greater (physical, data access, and virus security) High management and maintenance costs, although they are generally cheaper to maintain than mainframes

Birth of the Internet 1960’s - The U.S. Department of Defense (DoD) recognized the need to establish communications links between major U.S. military installations. The primary motivation was to maintain communications if a nuclear war resulted in the mass destruction and breakdown of traditional communications channels. 1970’s - When the Advanced Research Projects Agency Network (ARPANET) project began, no one anticipated that the network would grow to the extent that it did. Throughout the 1970s, more nodes or access points were added, both domestically and abroad.

Birth of the Internet 1980’s - The Domain Name System (DNS) was introduced in 1984, providing a way to map "friendly" host names to IP addresses. It was much more efficient and convenient than previous methods. 1990’s - ARPANET evolved into the Internet, with the U.S. government getting involved in pushing the development of the so-called information superhighway. Today, there are millions of sites that exist on the World Wide Web, with millions of host computers participating in this great linking.

Birth of the Internet

Starting and Restarting a Computer
Starting a computer is also referred to as booting the system. A "cold boot" is performed when the PC is turned on using the power button. Restarting a PC that has already been powered up is referred to as a "warm boot." This can be achieved by pressing the reset button on the front panel.

Shutting Down a Computer
Three ways to shutdown a computer To shutdown the computer, click on the Start button on the lower left corner of the Windows Taskbar and select Shut Down. Pressing Ctrl+Alt+Delete, and click Shut Down from the menu that displays. Pressing Alt+F4 at the desktop, and selecting Shut Down from the menu that displays. Note: It is extremely important not to power off the computer with the power switch. Most operating systems like Macintosh and Windows have a specific method for turning the system off.

The Desktop The main display screen in Windows is known as the desktop. Some of the icons on the desktop, such as My Computer, Network Neighborhood (or My Network Places), Recycle Bin, and My Documents, are shortcuts to those directories

The Desktop Located at the bottom of the desktop is the taskbar.
The taskbar contains the Start button, quick launch buttons, system tray, and the clock. The Start button, displays the Start menu. This menu allows access to virtually every program and function on the PC. Quick launch buttons are shortcuts to applications.

Windows Explorer (Windows 2000)
To create a shortcut (icon), right-click the program or file (in Windows Explorer) and select Create Shortcut. Explorer can be accessed in Windows 2000 by choosing Start > Programs > Accessories > Windows Explorer, from the Windows desktop.

Windows Explorer (Windows 9x)
To create a shortcut (icon), right-click the program or file (in Windows Explorer) and select Create Shortcut. With Windows 9x (95, 98, and Millennium), choose Start > Programs > Windows Explorer from the menu that displays.

Switching Between Windows
When more than one window is open, the user can switch between windows by pressing Alt +Tab. While holding down the Alt button, keep pressing Tab to find the desired window. Document windows can also be selected by clicking the desired document on the desktop taskbar, which displays at the bottom of the screen.

Viewing Basic System Information
To view information about the system, go to the Start menu and choose Programs > Accessories > System Tools > System Information. Here you can view information such as the type of operating system, the processor type, and the type and amount of Random-Access Memory (RAM) that is installed.

Adjusting the Screen Display
To adjust the screen display, first minimize all windows that are open. Right-click on empty space on the desktop and choose Properties to open the Display Properties window. Alternatively, from the Start menu choose Settings > Control Panel > Display.

Start Menu Options

Start Menu Options The Help feature provides tips and instructions on how to use Windows, along with an index and search function so information can be found easily.

Start Menu Options Find/Search
In Windows 95, 98, and Windows NT, Find is used to locate files, folders, and network connections to other computers and peripherals. In Windows 2000, Find has been renamed Search. Programs The Programs menu lists all of the programs that are installed on the computer.

Start Menu Options Documents
The Documents menu shows a list of the most recent documents that have been accessed or created. Run The Run feature is another method of starting a program, instead of clicking the program's shortcut icon on the desktop or on the list of programs within the Programs directory.

Application Software There are several types of application software:
Word Processor - an application that creates, edits, stores, and prints documents. Spreadsheet - numerical data is stored in cells that are arranged on a grid. Database - a collection of data that is organized so that its contents can be easily accessed, managed, and updated. Graphics applications - used to create or modify graphical images. Presentation applications - permit the organizing, design, and delivery of presentations in the form of slide shows and reports. Web browser - an application that is used to locate and display pages from the World Wide Web.

Measurement-related Terminology
Bit – The smallest unit of data in a computer. A bit can take the value of either one or zero, and it is the binary format in which data is processed by computers. Byte – A byte is a unit of measure used to describe the size of a data file, the amount of space on a disk or other storage medium, or the amount of data being sent over a network. One byte consists of eight bits of data. Nibble – A nibble is half a byte or four bits.

Kilobyte (KB) – A kilobyte is 1,024 (or approximately 1,000) bytes. Kilobit (Kb) – A kilobit is 1,024 (or approximately 1,000) bits. Megabyte (MB) – A megabyte is 1,048,576 bytes (or approximately 1,000,000 bytes). Note that a capital B indicates bytes while a lower case b indicates bits.

The following terms are standard measurements of the amount of data transferred over a network connection. Kilobits per second (Kbps) –Kbps is a data transfer rate of approximately 1,000 bits per second. Megabytes per second (MBps) –MBps is a data transfer rate of approximately 1,000,000 bytes per second. Megabits per second (Mbps) –Mbps is a data transfer rate of approximately 1,000,000 bits per second.

Hertz (Hz) – Is a unit of measurement of frequency. It is the rate of change in the state or cycle in a sound wave, alternating current, or other cyclical waveform. Common measurement of the speed of a processing chip. Megahertz (MHz) – One million cycles per second. common measurement of the speed of a processing chip. Gigahertz (GHz) – One billion (1,000,000,000) cycles per second.

Boolean Logic Gates Computers are built from various types of electronic circuits. These circuits depend on what are called AND, OR, NOT, and NOR logic "gates." These gates are characterized by how they respond to input signals.

Boolean Logic Gates Truth Table AND
The AND gate acts as follows: if either input is off, the output is off. AND is like multiplication Truth Table

Boolean Logic Gates Truth Table OR
An OR gate acts as follows: if either input is on, the output is on. OR is like addition Truth Table

Boolean Logic Gates Truth Table NOT
A NOT gate acts as follows: if the input is on, the output is off, and vice versa. NOT is the opposite of the input Truth Table

Boolean Logic Gates Truth Table NOR
The NOR gate is a combination of the OR and NOT gates and should not be presented as a primary gate. A NOR gate acts as follows: if either input is on, the output is off. Truth Table First perform the OR operation, then perform the NOT operation.

Numbering Systems Decimal (base 10) Binary (base 2)
uses 10 symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 Binary (base 2) uses 2 symbols 0, 1 Hexadecimal (base 16) uses 16 symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Numbering Systems Base 10 Base 2 Base 16

Binary Counting Decimal Binary Decimal Binary 1 2 3 4 5 6 7 8 9 10 11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1101 1 1110 10 1111 11 10000 100 10001 101 10010 110 10011 111 10100 1000 10101 1001 10110 1010 10111 1011 11000 1100 11001

Decimal to Binary Conversion Method 1
Convert the decimal number 192 into a binary number. 192/2 = 96 with a remainder of 0 96/2 = 48 with a remainder of 0 48/2 = 24 with a remainder of 0 24/2 = 12 with a remainder of 0 12/2 = 6 with a remainder of 0 6/2 = 3 with a remainder of 0 3/2 = 1 with a remainder of 1 1/2 = 0 with a remainder of 1 Write down all the remainders, backwards, and you have the binary number

Convert the decimal number 192 into a binary number. First find the largest number that is a power of 2 that you can subtract from the original number. Repeat the process until there is nothing left to subtract. = ’s used 1 64-64 = ’s used 1 32’s used 0 16’s used 0 8’s used 0 4’s used 0 2’s used 0 1’s used 0 Write down the 0s & 1s from top to bottom, and you have the binary number

Convert the decimal number 213 into a binary number. First find the largest number that is a power of 2 that you can subtract from the original number. Repeat the process until there is nothing left to subtract. = ’s used 1 85-64 = ’s used 1 *(32 cannot be subtracted from 21) ’s used 0 21-16 = ’s used 1 *(8 cannot be subtracted from 5) ’s used 0 5-4 = ’s used 1 *(2 cannot be subtracted from 1) ’s used 0 1-1 = ’s used 1 Write down the 0s & 1s from top to bottom, and you have the binary number

Binary to Decimal Conversion Method 1
From right to left, write the values of the powers of 2 above each binary number. Then add up the values where a 1 exist. = 181

Binary to Decimal Conversion Method 2
Start from the left with the first 1 in the binary number. Write down a 1 below it. Then look at the next number to the right if it is a 0, double the previous number and write it down if it is a 1, double the previous number and add 1 to it, then write it down Continue this until you reach the last 0 or 1 in the binary number. The last number you write down is the decimal equivalent of the binary number. Binary place value Binary number Conversion 1 3 6 13

Hexadecimal to Decimal Conversion
Base 16 Each number place represents a power of 16 Given the hexadecimal number 12A 1 X 256 = 256 2 X 16 = 32 A X = (A = 10 in hex) 298

Hexadecimal to Binary Conversion
To convert a hex number to a binary number, each hex bit represents 4 binary digits Given the hex number A 3 A is the decimal number 10 10 in binary is (binary number places - 4 bits) 3 is the decimal number 3 3 in binary is (binary number places - 4 bits) hex A 3 = in binary

Chapter 2 How Computers Work

Basic Functions of an Operating Systems
Input – Recognizing input from the keyboard or mouse. Processing –- Manipulating data according to the user's instructions. Output – Sending output to the video screen or printer. Storage – Keeping track of files for use later. Examples of storage devices include floppy disks and hard drives.

Bootstrap For an operating system to run, it must be loaded into the computer's Random Access Memory (RAM). When a computer is first turned on, it launches a small program called the bootstrap loader that is built into the computer's hardware. Specifically, the bootstrap is located on the BIOS chip, which resides on the system board. The bootstrap's primary functions are to test the computer's hardware and to locate and load the operating system into RAM.

Power-On Self Test To test the computer's hardware, the bootstrap program runs a program called power-on self-test or POST. In this test, the computer's Central Processing Unit (CPU) checks itself first and then checks the computer's system timer. The POST checks the Random Access Memory (RAM) by writing data to each RAM chip and then reading that data. Any difference indicates a problem. If the POST finds errors, it sends a message to the computer monitor. If the POST finds errors that cannot be displayed on the monitor, it sends errors in the form of "beeps." The POST sends one beep and the screen begins to display OS loading messages once the bootstrap has determined that the computer has passed the POST.

Motherboards Knowledge of the motherboard, also called the system board or main board, is crucial because it is the nerve center of the computer system. Everything else in the system plugs into it, is controlled by it, and depends on it to communicate with other devices on the system. It generally houses the CPU, the controller circuitry, the bus, RAM, expansion slots for additional boards, and ports for external devices. In addition, it contains the CMOS and other ROM BIOS and support chips providing varied functionality.

Motherboard Form Factors
Motherboards are usually described by their form factors, which describe their physical dimensions. The two most common form factors in use today are the Baby AT motherboard and the ATX motherboard. The ATX motherboard is similar to the Baby AT motherboard, except for a number of important enhancements. Most new systems come with the ATX motherboard form factor.

Motherboard Components
The major components on the motherboard include the chipset, CPU socket, expansion sockets, I/O support, BIOS, RAM sockets, power supply socket, CMOS chip, dipswitches and jumpers, and the memory cache.

Central Processing Unit
The CPU is one of the most important elements of the personal computer. On the motherboard, the CPU is contained on a single integrated circuit called the microprocessor. The computer will not run without a CPU. Often referred to as the brains of a computer, the CPU contains two basic components: Control unit Arithmetic/Logic Unit (ALU)

Control Unit Instructs the rest of the computer system on how to follow a program's instructions. It directs the movement of data to and from processor memory. The control unit temporarily holds data, instructions, and processed information in its arithmetic/logic unit. In addition, it directs control signals between the CPU and external devices such as hard disks, main memory, I/O ports, etc.

Processor Speed CPU descriptions as Pentium 133, Pentium 166, or Pentium 200 are well known. These numbers are specifications that indicate the maximum (reliable) operating speed at which the CPU can execute instructions. The CPU speed is not controlled by the microprocessor itself, but by an external clock located on the motherboard. The speed of the processor is determined by the frequency of the clock signal. It is typically expressed in megahertz (MHz), and the higher the number, the faster the processor.

Expansion Slots Expansion slots, also known as sockets, are receptacles on the computer motherboard that accept printed circuit boards. All computers have expansion slots that allow additional devices to be added. Video cards, I/O cards, and sound cards are examples of components that are located in expansion slots. The common expansion slots that are likely to be encountered include the following: Industry Standard Architecture (ISA ) Peripheral Component Interconnect (PCI ) Accelerated Graphics Port (AGP)

Monitors Computers are usually connected to a display, also called a monitor. Some key monitor-related terms are: pixels, refresh rate, resolution, and size. Pixels – Are picture elements. The screen image is made of pixels (tiny dots), which are arranged in rows across the screen. Each pixel consists of three colors: red, green, and blue (RGB). Dot pitch – A measurement of how close together the phosphor dots are on the screen. The finer the dot pitch, the better image quality (measured in millimeters).

I /O Ports All peripheral devices that connect to the computer such as printers, scanners, and so on, use connectors on the back of the computer known as ports. There are different types of ports on the computer that serve different purposes.

Serial Ports A serial port can be used to connect devices that use a serial interface such as a modem, scanner, mouse, etc. Generally, a PC can identify up to four serial ports, but the typical computer contains only two, referred to as COM1 and COM2. A serial port transmits data bits one after the other (serially) over a single line.

Parallel Ports A parallel port is a socket on the computer that is used to connect a printer or other peripheral device such as a portable hard disk, tape backup, scanner, or a CD-ROM. The parallel port contains eight lines for transmitting an entire byte (8 bits) across the eight data lines simultaneously. Parallel ports can be configured as LPT1, LPT2, or LPT3.

PS/2 Ports PS/2 keyboard or PS/2 mouse ports are used to connect your PC to its keyboard and mouse. Though both ports look identical, the mouse (green) and keyboard (purple) ports are not interchangeable. Usually both ports are color coded or labeled to avoid any confusion.

EIDE and SCSI Controllers
The internal hard drive (discussed later in this chapter) is connected to a disk controller with a cable. The hard drive and other devices can use one of two types of interface controllers to work with the computer. These include the Enhanced Integrated Drive Electronics (EIDE), and Small Computer System Interface (SCSI, pronounced "scuzzy") connections.

EIDE Controllers Enhanced IDE (EIDE) is the "new and improved" Integrated Drive Electronics (IDE) drive interface. Not confined to IDE's 528 MB of data, the EIDE interface can handle up to 8.4 GB or more. While IDE can support only two drives, EIDE can support up to four devices using two IDE cables.

SCSI Controllers The Small Computer Systems Interface (SCSI ) controller evolved from the Shugart Associates Standard Interface (SASI). Like EIDE, SCSI devices have the controlling electronics on each of the drives. A standard SCSI interface will allow up to seven devices to be connected to one SCSI adapter or controller. If the SCSI card is counted, it makes eight SCSI devices. Such devices may include hard drives, CD-ROM drives, taped drives, scanners, and removable drives. Each SCSI device in the chain, including the SCSI controller card is given a SCSI ID number from 0 to 7; #0 for the primary boot device (hard drive), and #7 for the SCSI controller card.

Hard Disk Drive The HDD has a much larger storage capacity than the floppy for long-term storage. It stores your programs and files, as well as the operating system. Typically, the HDD is an internal drive that cannot be removed from the computer.

Hard Disk Drive Components
All hard disk drives share a common set of components. These components include: Disk platters, read/write heads, head actuator assembly, spindle motor, logic/circuit board, bezel/faceplate, configuration jumpers, and interface connectors. Disk platters are the actual media on which data is stored in the hard disk drive. Read/write heads are used to access the media. The disk platters require a read/write head for each side. Spindle motor which spins the platters.

Interrupt Request Modern computers and operating systems owe their reliability to the organized way in which they handle internal transactions. Various hardware devices, for example, may want to tell the CPU that they have some information available that is ready for transfer. The devices indicate this by making an interrupt request, or IRQ. It is a general rule that IRQs CANNOT be shared.

Interrupt Request

Direct Memory Access Direct Memory Access (DMA) channels allow devices to bypass the processor and directly access the computer memory. Devices with a DMA channel assignment, as a result, gain the advantage of faster data transfers. DMA channels are typically used by high-speed communication devices for transferring large amounts of data at high speeds. Examples of such devices include sound cards, some network cards, some SCSI cards, some disk drives, and some tape backup drives.

I /O Address In addition to an IRQ, computer components also need to be assigned an I/O port number. An I/O port number is a memory address where data is temporarily stored as it moves in and out of the devices. The I/O address is very similar to a post office box.

I /O Address Frequently referred to I / O Addresses: 3F8 = COM1
3E8 = COM3 2E8 = COM4 378 = LPT1 278 = LPT2

Chapter 3 Assembling a Computer

Computer Cases There are four main types of computer cases: Desktop
Mini-tower Mid-tower Full tower Whether buying a tower or desktop, it is recommended that it conforms to the ATX standard and has at least a 250-watt power supply (300 watts is ideal.) The desktop case is considered the most difficult to upgrade.

Power Supplies The power supply is one of the most important parts that needs to be understood. The power supply unit provides electrical power for every component inside the system unit. The power supply plays the critical role of converting commercial electrical power (AC), into DC required by the components of the computer. There are two basic types of power supplies: AT power supplies – Designed to support AT-compatible motherboards. ATX power supplies – Designed according to newer ATX design specifications to support the ATX motherboard.

Power Supplies There are two major distinctions between the legacy AT and the new ATX power supplies. The AT power supply has two 6-pin motherboard power connectors (P8/P9) The ATX power supplies use a single 20-pin power connector (P1). In the ATX-compatible power supply, the cooling fan pulls air through the case from the front and exhausts it out the rear of the power supply unit. The AT design pulls air in through the rear of the power supply unit and blows it directly on the AT motherboard.

Power Supplies The power supply produces four (five in the ATX) different levels of well-regulated DC voltage for use by the system components. These are +5V, -5V, +12V, and -12V. In ATX power supplies, the +3.3V level is also produced and is used by the second-generation Intel Pentium processors.

Configuring the Motherboard
Configuring the motherboard typically means the following: Installing the CPU Installing the heat sink and fan Installing RAM Connecting the power supply cables to the motherboard power connectors and connecting miscellaneous connectors to the correct switches and status lights on the front case panel. Setting the system BIOS

Configuring the Connectors
For the disk controllers, always remember that a colored stripe on the data cable is pin-1. Most modern connectors are "keyed" by a missing pin or a blocked connector, so they cannot be fitted the wrong way. Usually, the colored wire(s) in a power cable are positive and the white or black wire(s) are ground or negative.

CPU Interfaces There are two main types of CPU interfaces.
Socket type (e.g., socket 7) - Socket 7 has been the standard interface, although the newer systems are now using different sockets. It is the only interface used by at least one generation of Intel Pentium processors (Pentium I) as well as AMD and Cyrix chips. Slot type (e.g., slot 1.) - Slot type interfaces use a slot similar to expansion cards. Slot 1 is the Single Edge Contact (SEC) interface used only by the Intel Pentium II processor family.

RAM There are two types of memory modules used on most PCs.
168-pin Dual In-line Memory Module (DIMM) cards 72-pin Single In-line Memory Module (SIMM) cards. Important When DIMM sizes are mixed on the motherboard, it is important to remember to put the DIMM with the largest memory size in the first bank. Each bank of memory for a SIMM has two sockets. You must fill the first bank before moving onto the next. Additionally, each bank must be filled with RAM modules that have the same access time and size.

Installing a Hard Drive or CD-ROM
Attaching the hard drive and CD-ROM are basically similar. First, the jumper settings should be properly set. The designation of a hard drive or CD-ROM drive as either master or slave is generally determined by the jumper configuration, not by the order in which the drive is daisy-chained to the other drive. The only exception is if the drive is jumpered (set to) "cable select" and both the system and ribbon cable support cable select.

Connecting Floppy Drives
The floppy drive exchanges data with the motherboard devices, including the microprocessor, via a 34-pin flat ribbon (data) cable Usually, a red stripe on the edge of the cable identifies pin-1. Lining the red-stripe edge with pin-1 of the drive connector or drive controller interface assures a correct alignment. Current system BIOS versions can support up to two floppy drives on one controller via a daisy chain cable arrangement. Cable pin-outs 10 through 16 are cross-wired between the middle drive connector and end drive connector, producing a twist that reverses the Drive Select (DS) configuration of the drive plugged into the end connector of the ribbon cable. This feature, called cable select, automatically configures the drive on the middle connector as Drive B and the drive on the end connector as Drive A.

Operating System Fundamentals
Chapter 4 Operating System Fundamentals

Operating Systems Operating Systems (OS) are software programs that control thousands of operations, provide an interface between the user and the computer, and run applications. An OS is designed to control the operations of programs such as Web browsers, word processors, and programs. Computers that are capable of handling concurrent users and multiple jobs are often called "network servers" or simply "servers." Servers have operating systems installed called Network Operating Systems (NOS).

Operating Systems There are three basic elements that make up the major design components of any operating system. These components are: User interface – A user interacts with the computer's OS through the user interface. Simply put, the user interface is the part of the operating system that a person can use to issue commands Kernel – This is the core of the OS. The kernel is responsible for loading and running programs (processes) and for managing input and output. File management system – The file management system is what the OS uses to organize and manage files. Most operating systems use a hierarchical file system in which files are organized into directories under a tree structure. The beginning of the directory system is referred to as the root directory.

Operating Systems Functions
Regardless of the size or complexity of the computer or its operating system, all operating systems perform the same basic functions: File and folder management Management of applications Support for built-in utility programs Access control to computer's hardware

Operating Systems Functions
What type of software has access to the BIOS?

Operating Systems Types - Basic Terminology
Multi-user – Two or more users running programs and sharing peripheral devices, such as a printer, at the same time. Multi-tasking – A computer's capability to run multiple applications at the same time. Multi-processing – Allows a computer to have two or more CPUs (Central Processing Unit) that programs share. Multi-threading – The capability of a program to be broken into smaller parts that can be loaded as needed by the OS. Multi-threading allows individual programs to be multi-tasked. Today, almost all operating systems are multi-user, multi-tasking, and support multi-threading.

Popular Operating Systems
Microsoft Windows 95, 98, ME – Windows is one of the most popular operating systems today. Windows is designed to run on PCs and to use an Intel-compatible CPU. Windows 9x systems are designed to be run and maintained by a single user. Microsoft Windows NT/2000/XP –Windows NT, 2000 and XP are operating systems that were designed to support multiple (concurrent) users and to run applications simultaneously. Both Windows NT and Windows 2000/XP have incorporated many networking features.

Popular Operating Systems
The Macintosh OS – The first Macintosh computers became available in January of 1984 and were designed to be very user-friendly compared to the existing DOS computers. The latest release of the Macintosh Operating System, OS X, is highly functional and is based on Unix as its core technology. UNIX – UNIX, which has been around since the late 1960s, is one of the oldest operating systems. UNIX has always been popular with computer professionals whose responsibility is to run and maintain computer networks. There are many different versions of UNIX today. One of the most recent is the extremely popular Linux.

Disk Operating Systems
Microsoft developed the Disk Operating System (DOS), also called MS-DOS, in 1981. DOS was designed then, for the IBM Personal Computer. Windows 98 and Windows 2000 both support DOS commands in order to address compatibility issues related with older applications. Simply put, DOS is a collection of programs and commands used to control the overall computer operation in a disk-based system.

Basic Elements of DOS The following are some of the basic things to remember when working with DOS. DOS is a command line operating system; it is not user-friendly. The best way to learn DOS is to use it. DOS can only run one program at a time. It is not multitasking. DOS can only run small programs and has memory limitations. DOS is an essential tool for IT professionals and is used extensively for troubleshooting.

DOS File Structure Programs and data are stored the same way a document would be filed in a folder in a file cabinet. In DOS, they are called files and are grouped together in directories. Directories are much like the folders in the file cabinet. Directories can be nested inside other directories, just like a folder placed inside another folder. Nested directories are referred to as subdirectories. Directories became known as folders in the Windows OS.

DOS Files A file is simply a block of logically related data, given a single name, and treated as a single unit, such as programs, documents, drawings and other illustrations, sound files, and so on. Files are referred to by filenames. In DOS, filenames can be up to 8 characters with an extension of 3 characters. (8 + 3) The extension is separated from the main portion of the filename by a period and it identifies what type of file it is. Example: mynotes.txt

DOS File Attributes In DOS, all files have attributes, which are a set of parameters that describe a file. The common attributes for DOS files include: Hidden File – The user will not see this type of file with any kind of normal file search in a DOS environment. Read Only – The user can open and read this type of file but cannot write or modify the file in any way Archive (backup) status System File – A file needed by the DOS operating system for a successful bootup

DOS Directory Structure
Hard drives organize the disk into directories and subdirectories. The main directory is known as the root directory. All other directories, if they exist, then radiate (branch out) from the root directory, similar to the branches of a tree. Locating any given file requires knowledge of three things: the drive, directory and subdirectory in which the file is found.

DOS Directory Structure
In MS-DOS, the format for specifying the path to a file is as follows: C:\directory name\subdirectory name\filename The first back slash indicates the root directory, which is present on all DOS disks The back slash (\) after each item signifies the presence of a directory or subdirectory

Basic DOS Commands In DOS, the main user interface is the command line. The command line is the space immediately following the DOS prompt, C:\> where C:\ represents the hard disk drive root directory, and '>' is known as the prompt. All the DOS commands are typed to the right of the prompt and executed by pressing the return (ENTER) key on the keyboard.

Basic DOS Commands

DOS Boot Disk To troubleshoot the problem, an alternate way of starting the system is needed. A DOS boot disk is a great tool to use to perform this task. One of its most useful functions is in booting a newly assembled computer to install the operating system. A DOS boot disk is just a floppy disk with the three necessary system files on it, including: COMMAND.COM IO.SYS MSDOS.SYS

Booting a System with a DOS Boot Disk
A DOS boot disk is used to boot a computer to the DOS Prompt. On the very first section of a DOS disk is a section called the boot sector. The boot sector contains information about how the disk is organized. Sometimes, it contains a small optional master boot record that can access a larger, more powerful bootstrap loader program, which is located in the root directory.

CONFIG.SYS The config.sys in most Windows 9x will be empty (plain text file) waiting for any changes that the user might want to add to the system. In the migration from DOS to Windows 9x, most of the values formerly located in this file have been moved to IO.SYS. If you want to override values in IO.SYS, enter the appropriate statements in Config.sys, including the values.

AUTOEXEC.BAT This file contains a batch of DOS commands that will automatically be carried out when DOS is loaded into the system. Examples of commands normally located in the Autoexec.bat file include: DATE – Causes DOS to prompt user for the date TIME – Causes DOS to prompt the user for the date and time DOSKEY – loads the DOSKEY

Boot Process When booting from a DOS boot disk, the boot process occurs in the following order: BIOS Bootstrap IO.SYS MSDOS.SYS CONFIG.SYS (if present) COMMAND.COM AUTOEXEC.BAT (if present)

Physical Memory Allocation
Four categories of system memory in the operating system includes conventional, upper/expanded, high, and extended memory.

Physical Memory Allocation
Conventional memory includes all memory addresses between 0 and 640KB. It is also known as base memory. Upper memory/Expanded memory includes memory addresses that fall between 640KB and 1024KB (1MB). Expanded Memory. This is memory that can be accessed in pages (16KB chunks) from a 64KB page frame, established in unused Upper Memory Blocks. EMM386.EXE controls expanded memory. Extended memory includes memory addresses above 1024KB. It is controlled be HIMEM.SYS The first 64KB of extended memory is called the High Memory Area (HMA). When activated, Windows 9x runs here.

Virtual Memory Also known as swap file or page file is used to describe memory that is not what it appears to be. Hard disk drive space is manipulated to seem like RAM. The combination of virtual memory and actual installed physical memory, gives the appearance of more memory than is actually installed on the system. Virtual memory is the basis of multitasking in Windows 9x.

General Fault Protection
Memory conflict can lead to a condition called General Protection Fault (GPF). A GPF will typically occur when an application attempts to violate the system integrity by one of the following ways: Tries to use a memory address or space owned by another application Tries to interact with a failing hardware driver Tries to have direct access to the system hardware

Windows 9x Operating System
Chapter 5 Windows 9x Operating System

Naming Files The terms directory and folder are used interchangeably to describe a place to store information. Windows 3.1 and DOS file names are limited to eight letters plus a three-letter suffix called an extension. Windows 98 and later allow extended filenames of up to 255 characters. Folder names use the same rules as file names. Never use these characters / \ ; : * ? " < > because they are associated with special functions when executing commands from a prompt. Legal or allowable characters include all other characters and numbers available on a standard computer keyboard.

Directories and Folders
To understand files, folders, and sub-folders, imagine a tree. The trunk is the starting place or the main part of the tree. Branches of the tree are folders. They connect to the trunk. Minor branches attach to these major branches as sub-folders. Files are like leaves attached to the major and minor branches inside (attached to) folders and sub-folders.

Directories and Folders
Windows Explorer displays the hierarchical structure of files, folders, and drives on a computer. It can be found by clicking on the Start button to access the Start menu, pointing to Programs and then clicking on Windows Explorer. Alternatively, right click on the Start button and choose Explore from the pop-up menu.

Windows Explorer

Recognizing File Types in Windows
The following file extensions describe the file format or the type of application that was used to create the file. *.doc – Microsoft Word or WordPad *.xls – Microsoft Excel *.dbf or *.dat – database files *.txt – ASCII text with no formatting (bold, underline, etc.) *.exe and *.com – executable programs *.sys – DOS or Windows driver files *.dll – Windows dynamic link libraries *.htm or *.html – Internet Hypertext Markup Language (web page) *.ini – Windows or other configuration files

System Properties The System Properties tool can be accessed from within the control panel by double clicking the system icon. The system properties window includes four tabs across the top. General Device Manager Hardware Profiles Performance

System Properties General tab (default tab) lists information relating to the system. This information includes operating system version, licensing information, and system specifics such as processor type and the amount of memory. Device Manager provides the user a list of all the hardware within the system and allows the user to view which system resources are being used. It can also be used to update device drivers, disable or enable devices, and change resource settings. Hardware profiles allow the user to have different hardware configurations for the same operating system. Performance tab displays information about the current system's performance statistics and allows access to the virtual memory and file system settings.

Add / Remove Programs Use Add/Remove Programs to remove programs that have been installed, to install Windows specific components that weren't installed initially, and to create a Windows startup disk. It is recommended that when you uninstall an application that you go into the Add/Remove Programs utility and click the "Uninstall…" button to uninstall the software. This will assure that the uninstalled application is removed from the system together with all its associated pieces.

Registry The Registry is a hierarchical database that is an efficient management system for all of the information needed by the Windows operating system. The Registry is made up of two files: System.dat User.dat. The system.dat file contains information about the hardware in the system. The user.dat file contains user specific information.

MSCONFIG.EXE MSConfig.exe is an excellent tool for users of Windows 98 and ME. It is not included in Windows 95. MSConfig.exe allows the user to control how the system is started by giving quick access to important Windows configuration/initialization files, including Config.sys, Autoexec.bat, System.ini, and Win.ini files. It also allows the user to select what programs are loaded automatically when the computer is booted.

Partitioning a Hard Drive
When a new hard drive is installed it is completely blank. There are no spaces where files and folders can be stored. To create those spaces, a hard drive must first be divided into logical sections. These sections are called partitions. Typically with DOS, when the hard drive is divided into more than one partition, the first partition is called to as the primary partition, while the second is called the extended partition. DOS can have up to four separate primary partitions, or three primary and one extended, two primary and one extended, or just one primary and one extended partition on one hard drive, depending on user needs.

Logical Drives When a hard drive is partitioned, including an extended partition, the extended partition uses up all free hard disk space not included in the primary partition(s). There can be only one extended partition per disk, but unlike the primary, it can be subdivided into multiple (up to 23) sections called logical drives.

FDISK FDISK is the partitioning program for MS-DOS, Windows 9x, Unix, and Linux. . When a hard drive is partitioned, the FDISK program creates the disk's boot sector. When the hard drive is formatted, the information to boot the operating system is recorded in the boot sector.

Formatting the Hard Drive
After the drive is partitioned, it must be prepared to store data. This process is called formatting. Formatting a hard drive creates magnetic tracks in concentric circles on the disk surface. These tracks are then broken up into chunks of 512 bytes called sectors. The combination of two or more sectors on a single track is called a cluster. A cluster is sometimes called a block. The size of each cluster depends on the size of the hard disk and the version of DOS in use. A cluster is the minimum unit DOS will use to store a file. This means that even if a file is only one byte long, one whole cluster will still be used to store the file.

File Allocation Table During formatting, a special file, called the File Allocation Table (FAT) is created and located in the disk's sector 0. FAT is a reference table that the OS uses to locate files on the disk. Newer DOS versions actually provide additional protection by storing a second (identical) copy of the original FAT created during formatting at another location. The first copy is the normal working copy while the second FAT is used as a backup measure in case the contents of the first FAT become corrupted.

FAT16 & FAT32 The original 16-bit FAT (called FAT16) is associated with DOS and Windows 3.x When a hard drive is formatted for installation of DOS, the FAT is created. A more efficient form of FAT(FAT 32), came with Windows 95 OSR2, Windows 98, and Windows Millennium Edition. These operating systems are collectively known as Windows 9x. When formatted for the installation of Windows 9x, FAT32 is created as the file system in the disk partition where the Windows 9x OS is to be installed.

Types of Formatting A drive may be formatted at a low-level or high-level, depending on the circumstances, although high-level formatting is more commonly used. Low-level formatting routine marks off the disk into sectors and cylinders, and defines their placement on the disk. (NEVER do a low-level format on an IDE drive unless the drive has failed miserably.) High-level format routine is performed by the format command in MS-DOS. This procedure creates logical structures on the disk that tell the system what files are on the disk and where they can be found. A high-level format should be performed when the hard drive is prepared for the OS installation.

Requirements for Installing Windows 98
When installing Windows 98, the following requirements must be met:

Troubleshooting Tools
Safe Mode - In this mode, Windows loads only the basic devices it needs to run. Once in Windows Safe Mode, check device manager to ensure that there are no conflicts with any devices causing the system to not operate properly. SCANDISK - Checks the surface of the disk and the files and inform you of any errors found. As a rule, always run Scandisk before the DEFRAG program. DEFRAG - It also attempts to pull together different pieces of the same file scattered all over the disk so the files can be more easily read by the system.

FDISK /MBR – This undocumented MS-DOS command can be very useful. MBR is short for Master Boot Record. Basically, it is the hard drive's table of contents. One common problem when the computer won't boot is that the Master Boot Record has been corrupted. FDISK /MBR will rebuild this crucial OS boot record.

From the Device Manager menu, it can be determined whether there are any problems with installed devices on the system. Within the device, problem conditions are indicated by either an exclamation mark, a red X, or an 'Other device' notation. An exclamation point (!) inside a yellow circle – A device is experiencing a direct hardware conflict with another device. A red "X" appearing at the device's icon – The device has been disabled, removed, or Windows is unable to locate the device. "Other Devices" appears in place of icon – Windows cannot recognize the device being installed; either the drivers have not been installed properly, they have been uninstalled, or the device is not working correctly and the driver needs an upgrade.

Device Drivers Device drivers give today's PCs the ability to add a wide variety of devices to the system. A device driver is software specially designed to enable the computer to 'see' the hardware or devices installed within the system. The device driver not only allows the basic system to recognize the presence of a device, but actually enables it to work with the device.

Creating a Startup Disk
A Windows 98 startup disk is essential if the system crashes, hangs upon startup, or when Windows 98 setup fails before completion. A Windows 98 startup disk is essential if the system crashes, hangs upon startup, or when Windows 98 setup fails before completion. The Windows 98 setup is easier with a Windows 98 startup disk. This section provides an overview of the Windows 98 startup disk, and how to make one. A Windows boot disk, also called a startup disk, is simply a floppy disk that allows the user to boot, or startup the computer without having to access the hard drive. A typical Windows boot disk contains all the necessary files that the operating system needs to get started.

Creating a Startup Disk
A Windows 98 startup disk can be created in two ways. The first way is to insert the floppy disk in the computer when prompted during setup. The second way is to create the startup disk after the Windows OS is already installed and running. The Windows Startup Disk tab is used to create a clean startup disk. Start --> Settings --> Control Panel --> Add/Remove Programs --> Click the Startup Disk tab

Uninstalling Windows 98 Windows 98 can be uninstalled if…
You upgraded from a previous version of Windows, for example, from Windows 95. The 'Save uninstall information' option was selected during Windows 98 setup. Note that when this option is selected, Setup creates the Winundo.dat and Winundo.ini files that contain the uninstall information.

Multimedia Capabilities
Chapter 6 Multimedia Capabilities

Multimedia Multimedia is a term typically used to mean the combination of text, sound, and/or motion video. Multimedia has been described as the addition of animated images, but typically it means one of the following: Text and sound Text, sound, and still or animated graphic images Text, sound, and video images Video and sound Multiple display areas, images, or presentations presented concurrently In live situations, the use of a speaker or actors and "props" together with sound, images, and motion video

PC Requirements to Run Multimedia
The types of computer hardware and software necessary to develop multimedia on the PC vary. The minimum hardware requirements include: computer monitor video accelerator card sound adapter card with attached speakers.

Key Multimedia Components
A microphone connected to a sound card to input sound. CD-ROMs and DVD players are used for input and output of multimedia. A connection to the Internet via a network interface card or a modem. Streaming of audio and video is very popular. Digital still pictures and video cameras connected to standard computer ports or special card adapters. A video capture card MPEG hardware and Web based movie players are used to play movies. Computer games via DVD or CD require specialized hardware.

The Video Card A video adapter (also called a display adapter or video board) is an integrated circuit card in a computer that provides digital-to-analog conversion, video RAM, and a video controller so that data can be sent to a computer's display. In a few cases, the video adapter is built in to the monitor. Today, almost all displays and video adapters adhere to the standard Video Graphics Array (VGA). In addition to VGA, most displays adhere to one or more standards set by the Video Electronics Standards Association (VESA). VESA defines how software can determine the capability of a display. It also identifies resolutions setting beyond those of VGA. These resolutions include 800 by 600, 1024 by 768, 1280 by 1024, and 1600 by 1200 pixels.

Display Characteristics
Displays use bits to describe color and how many colors can be displayed The number of bits used to describe a pixel is called bit-depth VGA video is 256 colors or 8-bit bit-depth 24-bit bit-depth is known as true color Dot pitch is the size of an individual beam that gets through to light up a point of phosphor on the screen measured in millimeters with a typical display having a .28 mm dot-pitch The actual sharpness of a display image is measured in dots-per-inch (dpi). The dots-per-inch is determined by a combination of the screen resolution and the physical screen size.

Dot pitch is a diagonal distance between the same color phosphor dots. The smaller the dot pitch, the greater the potential image sharpness.

On desktop computers, the display screen width relative to height, known as the aspect ratio, is generally standardized at 4 to 3 (usually indicated as "4:3"). Screen sizes are measured in either millimeters or inches diagonally from one corner to the opposite corner. Common desktop screen sizes are 15-, 17-and 19-inch. Notebook screen sizes are somewhat smaller. The projection technology used by most displays is Cathode Ray Tube (CRT) technology, which is similar to that used in most television sets. CRT technology requires a certain distance from the beam projection device to the screen in order to function. Using other technologies, displays can be much thinner and are known as flat-panel displays.

Media Formats Two data-compression standards are commonly used with digitized video. These are the Joint Photographic Experts Group (JPEG) and the Moving Picture Experts Group (MPEG) compression standards. Other Compression Standards Indeo compression standard, developed by Intel. Another compression/decompression (codec) standard supported by Video for Windows is Cinepak. This standard uses an AVI file format to produce 40:1 compression ratios and 30-frames per second capture, at 320-by-200 resolution.

Media Compression JPEG provides enough compression to allow single-frame digitized images to fit on disk drives, but full-motion pictures were going to need much greater compression to be useful on current technology. Therefore, the MPEG format was developed. MPEG has compression ratios up to 200:1, with high-quality video and audio. The MPEG standard includes specifications for audio compression and decompression in both MPEG1 and 2. MPEG1 supports a very near CD-quality stereo output, at data rates between 128kbps and 256kbps. The MPEG 2 specification supports CD-quality surround-sound (four-channel) output.

AGP Cards Newer Pentium systems were the first to include an advanced Accelerated Graphics Port (AGP) interface for video graphics. The figure below shows an AGP interface and its position on the motherboard. The AGP interface is a variation of the PCI (see Chapter 2) bus design that has been modified to handle the intense data throughput associated with 3 dimensional graphics.

Video Capture Cards Video capture software is used to capture frames of television video and convert them into digital formats that can be processed by the system. One of the popular file formats for video is the Microsoft Audio Visual Interface (AVI) format. Video capture cards are responsible for converting video signals from different sources into digital signals that can be manipulated by the computer. As in the audio conversion process, the video card samples the incoming video signal by feeding it through an A-to-D (analog-to-digital) converter. One of the jobs of the video capture card is to convert the YUV format into an RGB VGA-compatible signal. YUV is a video encoding format that is different than RGB.

Video Card Installation
After the video card has been installed and the monitor has been connected to the video card and plugged into the power outlet, it will be necessary to install the correct drivers for the video card. The Windows 9x operating systems should detect the video card, start the system with basic VGA video drivers, and ask you if you want to install the manufacturer's video drivers. The Windows 2000 operating system is even more proactive. It will detect the new video card, tell you that it has found the new card, and then automatically load its video drivers. The only time that you should need to be directly involved with the system's video drivers is when PnP fails or the video card is not recognized by the operating system.

Video Memory and Resolution
Monitors are analog, not digital devices. In order for the monitor to work, the digital information in the video memory must be translated into analog form for export to the monitor screen. This is the role of the Random Access Memory Digital-to-Analog Converter (RAMDAC) chip. The RAMDAC chip reads the video memory contents, converts it to analog, and sends it over a cable to the video monitor. The quality of this chip impacts the quality of the image, speed of the refresh rate, and maximum resolution capability. Refresh rate refers to the number of times per second that the video display screen can be redrawn.

Video Memory and Resolution
The video chip set relies on video memory to render the image requested. The basic element of every video image is a dot (or pixel). Many dots comprise what you see displayed on the monitor. Every dot has a location reserved in video memory. The maximum number of dots, which can be displayed, relates to the resolution. Resolution is expressed as a pair of numbers. Each pair of numbers represents the maximum possible number of dots on a horizontal and vertical axis. The basic VGA resolution is 640 by 480. The higher the resolution, the sharper and clearer the image.

Sound Cards Audio is an integral component of the multimedia experience, but for a PC to have audio capabilities, it requires the use of a sound card. A sound card is a device (either in the form of an expansion card or a chipset) that allows the computer to handle audio information. Input – Sound cards can "capture" audio information from many different sources. These sources include microphones, CD players, DAT, and MIDI devices. Processing – The processing capability of a sound card allows it convert audio information in different formats as well as add effects to the sound data. Output – Simple sound card output devices include headphones and speakers while more complicated devices consist of surround-sound digital theatre systems, DAT and CD recorders, and other musical devices

Sound Cards Sound cards produce audio (synthesize) using three distinct methods: Frequency Modulation (FM), Wavetable, and Musical Instrument Digital Interface (MIDI). FM synthesis - creates waveforms that best match the instrument playing. Wavetable - sound cards use actual digitized samples of real instruments to reproduce audio. MIDI - is a combination of hardware and software that allows the sound card to control actual musical instruments and use these instruments to output the audio.

Sound Production and Quality
The quality of a sound card is determined by its bit depth, sampling rate, and feature set. Bit depth – Refers to the sample size and bus size of the sound card. Sampling rate – The rate at which the card can record audio information. Today's 16-bit sound cards are capable of sampling at 128kHz and beyond. Feature set – Includes additional features such as: 3-D audio co-processors, device controllers, and digital output options. Sound cards can also act as device controllers that have built-in SCSI, RAID, or FireWire (IEEE 1394) controllers. Many higher-end sound cards also offer digital output ports such as Toslink (a fiber optic connector) and coaxial to allow connection to home theatre systems.

CD-ROMs CDs are 120mm in diameter, 1.2mm thick, and can store up to 800 MB of information. CD-ROM drives can be mounted internally in the computer or as an external drive. They connect either directly to an external port on the computer (such as USB, FireWire, or parallel) or to a controller installed in one of the computer's expansion slots (usually SCSI). Common internal connections include IDE and SCSI. IDE communication cables are 40-pin ribbon cables that connect to the drive and the motherboard.

CD-R and CD-RW Currently there are two major types of CD recorders: CD-R and CD-RW. CD-R – CD-R stands for Compact Disc - Recordable and was the first of the two technologies conceived. CD-RW – CD-RW stands for Compact Disc - Rewritable. A CD drive that can write at 3000kb per second is shown as having a 20x (or 20 times 150kb) write speed. A drive listed as 24x/40x has a write speed of 24x and a read speed of 40x.

CD Recording Formats

Windows NT/2000/XP Operating Systems
Chapter 7 Windows NT/2000/XP Operating Systems

File Systems The main purpose of the file system is to store and retrieve data from the computer hard disk. How the data is organized, optimized, and retrieved comes from the file system on the hard drive. There are three different file systems available in the Windows Operating System Environment: FAT16, FAT32, and NTFS. When using Windows NT, 2000, or XP, the best file system to use would be NTFS. Both FAT16 and FAT32 file systems maintain two copies of the FAT (the default and backup copy), but only FAT32 can use the backup copy as well as the default copy.

FAT16 The 16-bit FAT (FAT16) is used for most hard drives with DOS, Windows 3.1, and the first version of Windows 95. It limits the file names to eight characters with a three-letter extension. The FAT16 file system can only recognize partitions up to 2 GB in size. In the FAT16 file system, the root directory can be located only at the beginning of the hard disk. This poses problems if this part of the hard disk becomes damaged.

FAT16 The FAT structure also maintains a set of attributes for each file. S which stands for a system dataset H which means that the file is hidden in the directory display A which means that the file will be archived the next time the disk is backed up R which will make the file Read-Only.

FAT32 FAT32 is still based on the original FAT system and works in a similar fashion in order to remain compatible with existing programs, networks, and device drivers. The FAT32 file system was designed to support hard drives up to 2048 GB. FAT32 file system, the root directory can be located anywhere on the hard disk. This is very useful because if the section of the hard disk containing the root directory were to become damaged now, the root directory could be moved to another section of the hard disk and the damaged portion of the hard disk could be repaired.

NTFS The Windows NT File System (NTFS) supports all Windows NT/2000/XP operating systems. NTFS5 (the latest version) also includes a feature called disk quotas, which provide the system administrator with the ability to assign limits to the amount of hard disk space that users are allowed to occupy on the server or workstation. NTFS file system provides support for added features like file and directory security by using Discretionary Access Control Lists (DACL) and System Access Control Lists (SACL).

NTFS The Windows NT/2000/XP operating systems were designed to appeal to the corporate and business market. If the system crashes, NTFS can examine the log file and use it to restore the disk to a consistent state with minimal data loss. This feature is called Fault Tolerance.

High Performance File System
HPFS) is a seldom used and much more obscure type of file system but it is worth mentioning only because the OS/2 software that uses this file system is still in use today. Microsoft did use this file system with its Windows 3.51 operating system. The HPFS file system directory structure was the same as the FAT file system but allowed long file names of up to 254 characters. Another aspect of HPFS was its ability to map hard disks up to 8 GB instead of 2 GB. Instead of clusters as the unit of management on the hard disk, HPFS used physical sectors.

Sectors and Clusters The hard disk is divided into 512-byte pieces called sectors. The sectors are then grouped into larger pieces called clusters. Each cluster can hold only one file. The size of the clusters is determined by the size of the partitions made on the hard disk.

NTFS Security and Permissions
Windows NT/2000/XP has enhanced system security features like file encryption and the ability to set permissions on files as well as directories or folders. File and directory permissions are used to specify which users and groups can gain access to files and folders and what they can do with the contents of the file or folder. Another security feature included with the Windows 2000/XP operating systems, provided NTFS is used, is encryption. These features are only available in the Windows NT/2000/XP operating systems if NTFS is used and not the FAT file system.

Folder Permissions

File Permissions

Encryption Microsoft provides a specific file system for encryption called the Encrypting File System (EFS). This provides administrators with the means to apply encryption to a file or folder that only the person who encrypted the file can view. The administrator can specify the users who can view the file as well. Users can be granted access to the file if they are assigned a public key.

Windows 2000 Boot Process The Boot Process of the Windows 2000 operating system is very different from Windows 9x. The Windows 9x boot process is much simpler and straightforward. The Windows 2000 boot process occurs in five stages: The preboot sequence The boot sequence The kernel load The kernel initialization The logon process

Preboot Process The first step in the Boot Process after the power is turned on to the computer is the Power On Self Test (POST). After the POST routine is complete, the computer will locate a boot device, and load the Master Boot Record (MBR) into memory, which in turn locates the active partition and loads it into memory. The MBR allows programs such as the Disk Operating System to load into RAM.

Boot Sequence The boot sequence begins to gather information about hardware and drivers. NTLDR is the key component of this step. NTLDR uses the following files: Ntdetect.com, Boot.ini, and Bootsect.dos (The Bootsect.dos file will only be used in the event that the computer is set up to dual-boot.) The Boot.ini file enables the display of the boot menu on the screen. Ntdetect.com will detect hardware Once Ntdetect.com has collected the hardware information, NTLDR will load Ntoskrnl.exe and pass that information.

Kernal Initialization
Kernal Load The Kernel Load phase begins with Ntoskrnl.exe loading along with the Hal.dll file. Kernal Initialization This simply means that it is recognizing everything that was loaded previously so that NTLDR can now give control to the operating system kernel. The operating system can now begin the final stages of loading. The Graphical User Interface (GUI) is now seen and it will show a status bar indicating that the GUI is now loading.

Logon The Logon screen begins the final step in the boot-up process.
Although this is the final step, it is not considered a completed or successful boot until a user logs on.

Device Drivers Device drivers are programs that basically tell the operating system how to control specific devices. They act as an interface between the operating system and the device, which allows them to recognize and communicate with each other. The ability to add many devices to modern computers to expand their capabilities has become increasingly easier with the advances made in Plug-and-play Technology. The goal of Plug-and-play is to create a computer whose hardware and software work together to automatically configure devices and assign resources.

Administrative Tools The Administrative Tools utility is a powerful Windows NT/2000/XP System Tool that enables the administrator to control just about everything related to the local computer. From this utility, permission to log on to the computer can be controlled by creating Local User accounts. The Disk Management utility allows the administrator to control and manipulate the computer hard drives. There is also a Services tab that can start or stop any of the programs that are running on the computer.

Disk Types There are two types of disks that are available in Windows 2000 and XP, basic disks and dynamic disks. Basic Disk storage is typically referred to as the industry standard and is identified by a hard drive that is divided into partitions. When using Dynamic Disk Storage, multidisk volumes are referred to as hard disk space. This is because the hard drives are no longer dealt with as if they were one complete disk divided by partitions, but rather as multidisk volumes.

Dynamic Disk Volumes The three types of volumes that can be created with Windows 2000 professional are simple, striped, and spanned volumes. Simple Volume – Acts as a basic disk that will contain disk space from a complete single disk and is not fault tolerant. Spanned Volume – This volume will include disk space from multiple disks. There can be up to 32 disks in a spanned volume. Striped Volume – Also known as RAID-0, a stripped volume combines areas of free space from multiple hard disks, up to 32, into one logical volume.

Dynamic Disk Volumes Mirrored and RAID-5 volumes are types of volumes that can only be created with the Windows 2000 Server operating system. Mirrored volumes provide fault tolerance. It contains two identical copies of a simple volume that stores the same data on two separate hard drives. RAID-5 Volume - in the event that one of the drives should fail, the remaining two disks recreate the data automatically without having to shut down the server.

Networking Fundamentals
Chapter 8 Networking Fundamentals

Computer Networks A computer network is defined as having two or more devices (such as workstations, printers, or servers) that are linked together for the purpose of sharing information, resources, or both. The need to share information is an important part of the development of computer networks. Computer networks offer file and print services. This avoids duplication, conserves resources, and allows for the management and control of key information.

Network Administration
The ongoing task of maintaining and adapting the network to changing conditions belongs to network administrators and support personnel. Network administrator responsibilities include setting up new user accounts and services, monitoring network performance, and repairing network failures. They evaluate new technologies and requirements, administrators must measure the benefits of the new features against the issues, costs, and problems that they may introduce to the network.

Data Transmission The data channels over which a signal is sent can operate in one of three ways: simplex, half-duplex, or full-duplex. Simplex is a single one-way baseband transmission. Half-duplex transmission is an improvement over simplex because the traffic can travel in both directions. Full-duplex transmission operates like a two-way, two-lane street. Traffic can travel in both directions at the same time.

Peer-to Peer Networks In a peer-to-peer network, the networked computers act as equal partners, or peers, to each other. As peers, each computer can take on the client function or the server function alternately. In a peer-to-peer network, individual users control their own resources. They may decide to share certain files with other users and may require passwords before they allow others to access their resources. A peer-to-peer network works well with a small number of computers, perhaps 10 or fewer.

Local Area Networks LANs connect many computers in a relatively small geographical area such as a home, an office, a building, or a campus. The general shape or layout of a LAN is called its topology. LANs require the networked computers to share the communications channel that connects them. The communications channel that they all share is called the medium.

Wide Area Networks WANs connect computers in a large geographical area such as cities, states, and countries. Wide area connections between computers use point-to-point, serial communications lines. These lines are called point-to-point because they connect only two computers, one on each side of the line. Wide area connections make use of the communications facilities put in place by the utility companies, called common carriers, such as the telephone company. WANs typically connect fewer computers than LANs and normally operate at lower speeds than LANs. WANs, however, provide the means for connecting single computers and many LANs over large distances.

Circuit-switched vs. Packet-switched
In a circuit-switched network, a connection is established and all data is transmitted over that circuit (telephone system). In a packet-switched network, each individual packet of data can take a different path. Internet traffic uses packet-switching technology.

Network Interface Card
A Network Interface Card (NIC) is a device that plugs into a motherboard and provides ports for the network cable connections. It is the computer's interface with the LAN. There are several important considerations to bear in mind when selecting a NIC to use on a network: The type of network – NICs are designed for Ethernet LANs, Token Ring, FDDI, and so on. The type of media –such as twisted-pair, coaxial, fiber-optic, or wireless. The type of system bus –PCI or ISA.

Setting the IP Address In a TCP/IP-based LAN, PCs use Internet Protocol (IP) addresses to identify each other. An IP address is a 32-bit binary number. is an example of an IP address. This type of address is described as a dotted decimal representation. A secondary dotted decimal number, known as the subnet mask, always accompanies an IP address. The dotted decimal number is a subnet mask. The IP address that is entered is unique for each host and resides in the computer driver software for the NIC.

DHCP Servers The most common and efficient way for computers on a large network to obtain an IP address is through a Dynamic Host Configuration Protocol (DHCP) server. DHCP is a software utility that runs on a computer and is designed to assign IP addresses to PCs. The IP address information that a DHCP server can hand out to hosts that are starting up on the network includes the following: An IP address A subnet mask Default Gateway Optional values, such as a Domain Name System (DNS) server address

Default Gateway The default gateway is the "near side" interface of the router, the interface on the router to which the local computer's network segment or wire is attached. In order for each computer to recognize its default gateway, the corresponding near side router interface IP address has to be entered into the host Internet Protocol (TCP/IP) Properties Dialog Box. The default gateway allows communication with other networks.

Domain Name System Most hosts are identified on the Internet by friendly computer names known as domain names. The Domain Name System (DNS) is used to translate computer names such as cisco.com to their corresponding unique IP address.

Physical Topologies The physical topology defines the way computer and other devices are connected.

Physical vs. Logical Topology
Networks can have both a physical and logical topology. Physical topology – Refers to the layout of the devices and media. Logical topology – Refers to the paths that signals travel from one point on the network to another. That is, the way in which data accesses media and transmits packets across it. A network can have a one type of physical topology and a completely different type of logical topology or they can be the same.

Types of Media Coaxial cable - copper-cored cable surrounded by a heavy shielding. Uses BNC connector. Twisted pair - Shielded and Unshield Shielded - Shielded Twisted-Pair (STP) cable combines the techniques of cancellation and the twisting of wires with shielding. Uses STP connector Unshielded Twisted-Pair (UTP) cable is used in a variety of networks. It has two or four pairs of wires. Uses RJ45 connector Fiber-optic cable is a networking medium capable of conducting modulated light transmissions.

Common Networking Devices
Hub - a device that is used to extend an Ethernet wire to allow more devices to communicate with each other. Bridges connect network segments. The basic functionality of the bridge resides in its ability to make intelligent decisions about whether to pass signals on to the next segment of a network. A switch is sometimes described as a multi-port bridge. A switch is a more sophisticated device than a bridge Routers are the most sophisticated internetworking devices discussed so far. They are slower than bridges and switches, but make "smart" decisions on how to route (or send) packets received on one port to a network on another port.

Ethernet The Ethernet architecture is now the most popular type of LAN architecture. The Ethernet architecture is based on the IEEE standard. The IEEE standard specifies that a network implements the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method.

Token Ring IBM originally developed Token Ring as reliable network architecture based on the token-passing access control method. Token Ring standards are defined in IEEE

Fiber Distributed Data Interface
FDDI is a type of Token Ring network. Its implementation and topology differ from the IBM Token Ring LAN architecture, which IEEE governs. As its name implies, FDDI runs on fiber-optic cable, and thus combines high-speed performance with the advantages of the token-passing ring topology.

OSI Model

TCP/IP Utilities Ping is a simple but highly useful command-line utility that is included in most implementations of TCP/IP. Ping works by sending an ICMP echo request to the destination computer. The receiving computer then sends back an ICMP echo reply message.

TCP/IP Utilities TCP/IP configuration information can be displayed using different utilities, depending on the operating system: Ipconfig – Windows NT and Windows 2000 (command-line) Winipcfg –- Windows 95,98, and 2000 (graphical interface) Ifconfig – UNIX and Linux (command-line) Config – NetWare (server console)

Preventative Maintenance
Chapter 10 Preventative Maintenance

Elements of Preventative Maintenance
The main goal of any preventive maintenance program is to preempt problems before they happen. There are three questions that need to be addressed when developing a preventive maintenance program: When? Why? and How? When is the best time to prevent problems from happening? Why is this maintenance being done now? How is this system to be maintained?

Tools and Equipment Every technician's toolbox should contain a few important pieces of equipment. These items include anti-static vacuum cleaners, canned air, various solvents, and lint free cloths. Anti-static vacuum cleaners should be used whenever vacuuming computer components since normal vacuum cleaners generate static. Canned air is one of the most useful tools besides lint-free cloths.

Environmental Guidelines
As with other computing devices, a computer eventually comes to an end-of-life. Eventually, the question arises: What to do with the old computers or parts? Can they simply be placed in the garbage bin so that they are hauled to the landfill and buried? Computers and peripherals contain some environmentally unfriendly materials. Most computer components are either hazardous or contain some level of hazardous substances.

Environmental Guidelines
Computer printed circuit boards consist of plastics, precious metals, fiberglass, arsenic, silicon, gallium, and lead. CRTs (monitors) contain glass, metal, plastics, lead, barium, phosphors, and rare earth metals. Batteries from portable systems can contain lead, cadmium, lithium, alkaline manganese, and mercury.

Disposal of Batteries Batteries often contain rare earth metals that can be harmful to the environment. Typically, batteries from portable computer systems can contain lead, cadmium, lithium, alkaline manganese, and mercury. These metals do not decay and will persist in the environment for many years if not carefully disposed of. The desired method for the proper disposal of batteries is recycling, if possible.

Disposal of Monitors (CRT)
CRTs that have come to an end-of-life must always be handled with care due to the potentially lethal voltage that is maintained even after being disconnected from power. According to the U.S. Environmental Protection Agency (EPA) CRT monitors contain four pounds of lead on average. Like the case of batteries, all or most of the components of end-of-life CRT monitors can be salvaged or recycled.

Material Safety and Data Sheet (MSDS)
To determine if a material used in PC repairs or preventive maintenance is classified as hazardous, consult the Material Safety Data Sheet (MSDS). All hazardous materials are required to have Material Safety Data Sheets (MSDS) that accompany them when they change hands.

Material Safety and Data Sheet (MSDS)
MSDS are a valuable source of information and typically contain the following information: The name of the material Its physical properties Any hazardous ingredients it contains Reactivity data, including fire and explosion data Spill or leak procedures Any special precaution information Health hazard information Any special protection information

Creating a ESD-Free Environment
In order to avoid ESD, it helps to know the conditions in which it is most likely to occur. When the humidity is low, the potential for ESD increases dramatically. Also, if the temperature is cool or if there is carpeting on the floor, the potential for static electricity is higher. A few key elements to a good working area should be anti-static tile on the floors, grounded workbenches with anti-static mats, and wrist straps. The area should be clean and well lit as well as have a climate control system that raises the relative humidity above 50%. If all of these elements are in place, the risk of ESD will be significantly reduced.

Preventative Maintenance - Computer
There are many things that can cause a computer system to fail physically. The most common are dust buildup, extreme temperatures, and rough handling. If a computer isn't regularly cleaned, dust can build up on the components inside the computer, such as on the fan bearings or on the printed circuit boards. In order to clean inside the computer case properly, unplug the unit and move it away from other equipment. Use a can of compressed air, making sure to follow the directions carefully, to blow out all of the dust within the case. This simple process should be done at least once a year in not very dusty areas and two or three times a year in very dusty areas.

Preventative Maintenance - Monitor
When cleaning a display, some common sense should be used. Make sure the device is unplugged from the wall so as not to cause damage if water ends up inside. Using a damp cloth with a mild detergent, wipe down the entire display unit to remove any dust buildup. ?

Preventative Maintenance - File Issues
There are several utilities that are included with DOS and Windows that help maintain system integrity. If run on a regular basis, these utilities can make the system run faster and more efficiently. Scandisk Defrag CHKDSK /f

Power Issues Blackouts, brownouts, noise, spikes, and surges are all examples of power interruptions that can cause system malfunctions or even complete system failure. Blackouts – Are the complete loss of power. Brownouts/Sags – Sags and brownouts are a drop in power. A sag is a brownout that lasts less than a second. These incidents occur when voltage on the power line falls below 80 percent of the normal voltage. Spikes – Are sudden increases in voltage that are much higher than normal levels. Surges – Are a brief increase in voltage usually caused by high demands on the power grid in a local area.

Power Suppressors & UPS
Three different devices can be used to protect sensitive computer equipment from the commonly occurring power events: Surge suppressors – Can make sure that the voltage going to a device stays below a certain level. However, they are useless during brownouts or blackouts. Standby Power Supplies (SPS) – Are equipped with a backup battery to supply power when the incoming voltage drops below the normal level. When the voltage slips, the battery kicks in to provide DC power to a power inverter, which converts it to AC power for the computer. Uninterruptible Power Supplies (UPS) – Are comparable to standby power supplies; however, a UPS runs off the battery power the entire time it is in use.

Troubleshooting PC Hardware
Chapter 11 Troubleshooting PC Hardware

Troubleshooting Basics
Effective troubleshooting uses techniques to diagnose and fix computer problems. A series of logical steps speeds up the troubleshooting process.

Troubleshooting Tools and Aids
Every technician should have a good toolset. The typical toolset will include items such as: Flat-head screwdriver Phillips-head screwdriver Nut drivers Needle-nose pliers Diagonals or crosscut pliers Mirror - helps see into very tight spots Flashlight

The toolset should include a digital multimeter, which is a measuring device. A digital multimeter can measure voltage, amps, and ohms in both alternating and direct current. A digital multimeter can be used to test power supplies, DC/AC voltage and polarity, resistance (Ohms), diodes, continuity, coaxial cable, fuses, and batteries.

Troubleshooting Tools and Aids (Digital Multimeter)

Loop-back plugs can provide important diagnostic information while troubleshooting serial and parallel ports (printers). Loop-back testing works by sending signals out and verifying if the correct input is received back. Diagnostic information can be gained from individual pins, ports, controllers, and printer output.

Field Replaceable Units
Devices that can be replaced or added in the field are called Field Replaceable Units (FRU). FRUs do not require any soldering and are easy to remove and install. Common FRUs are: Monitors lPower Supply Keyboard/ mouse lRAM: DIMMs, SIMMs, RIMMs, etc. Modular expansion cards lFloppy and fixed disk drives Most microprocessors lMotherboard

Input Devices Input devices such as a keyboard, mouse, scanners, and digital cameras transfer data into the computer. Most input devices are detected at startup. When troubleshooting input devices, always start with the simple solutions. Check to make sure the device is properly connected. After checking the physical connections of the input device, try rebooting the computer. Pay attention to any errors that display during startup. The errors will be indicated either as a text error on the video display or a POST beep code (a keyboard is not properly connected, the user might get a beep code or a "301 error message.“)

SCSI Interface Issues SCSI drives require a separate controller from the IDE controller. The SCSI bus operation and the transfer rate are controlled by adapter settings. If there is a transfer speed mismatch amongst the SCSI controllers, the drive might have I/O errors. As a rule, attach the SCSI controller set to the last SCSI ID, which is SCSI ID #7. Input/Output errors might result if the SCSI ID is not set to 7. An important consideration with SCSI IDs is, the higher the SCSI ID, the higher the priority. The actual ID priority is 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8.

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