Presentation on theme: "TRAINERS TRAINING ON COMPUTER MAINTENANCE AND TROUBLE SHOOTING"— Presentation transcript:
1TRAINERS TRAINING ON COMPUTER MAINTENANCE AND TROUBLE SHOOTING
2Seminar Workshop Objectives: Acquire better understanding on the different types of Operating System for the proper diagnosis and repair of computer problems.Enhance skill in installing different types of Application Software and in configuring different peripherals.Develop expertise in network and trouble shooting.
4MotherboardsMotherboards (also called mainboards) are actually a carryover from architecture used for years in mainframe computers. Various circuit cards performing various functions all plug into many similar sockets on a common circuit board. Each circuit card performs a unique function in the computer and gets its power from the socket.
5MSI 694D Pro AR Dual Flip Chip Socket 370 motherboard The Abit KT-7A supports Advanced Micro Devices (AMD) processors and has the KT-133A chipset. The card slots on the Abit KT-7A, from bottom to top in the image below, shows that ISA has one slot, PCI has six slots and AGP has one slot. A special fan cools the chipset.MSI 694D Pro AR Dual Flip Chip Socket 370 motherboard
6Abit KT-7A AMD Processor Motherboard A partial view of the TechRam S3ProM motherboard shows slots: From bottom to top, ISA has one slot, PCI has two slots, audio modem riser (AMR) has one slot, and AGP has one slot.Abit KT-7A AMD Processor Motherboard
7Data Bus WidthModern Pentium class motherboards have a data bus with 64 bits. That is the width of the data highway that goes in and out of the processor. The Pentium processors, however, do use 32-bit registers to handle 32-bit instructions.Bus speeds and widths have increased due to faster processors and the needs of multimedia applications.
8Typical bus names and widths are: Industry Standard Architecture (ISA) - 8 or 16 bitsExtended Industry Standard Architecture (EISA) - 8 or16 bitsMicrochannel Architecture (MCA) - 16 or 32 bitsVESA Local Bus (VLB) - 32 bitsPeripheral Component Interconnect (PCI) - 32 or 64 bitsAccelerated Graphics Port (AGP ) - 32 bits
9MicroprocessorsA microprocessor -- also known as a CPU or central processing unit -- is a complete computation engine that is fabricated on a single chip. The first microprocessor was the Intel 4004, introduced in The 4004 was not very powerful -- all it could do was add and subtract, and it could only do that 4 bits at a time. But it was amazing that everything was on one chip. Prior to the 4004, engineers built computers either from collections of chips or from discrete components (transistors wired one at a time). The 4004 powered one of the first portable electronic calculators.
11Information about this table: The date is the year that the processor was first introduced. Many processors are re-introduced at higher clock speeds for many years after the original release date.Transistors is the number of transistors on the chip. You can see that the number of transistors on a single chip has risen steadily over the years.Microns is the width, in microns, of the smallest wire on the chip. For comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises.Clock speed is the maximum rate that the chip can be clocked at. Clock speed will make more sense in the next section.
12Information about this table: Data Width is the width of the ALU. An 8-bit ALU can add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit ALU would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction.MIPS stands for "millions of instructions per second" and is a rough measure of the performance of a CPU.
13Computer Memorymemory is technically any form of electronic storage, it is used most often to identify fast, temporary forms of storage. If your computer's CPU had to constantly access the hard drive to retrieve every piece of data it needs, it would operate very slowly. When the information is kept in memory, the CPU can access it much more quickly. Most forms of memory are intended to store data temporarily.A Sony Flash Memory Stick
14Types of Electronic Memory RAMROMCacheDynamic RAMStatic RAMFlash memoryMemory SticksVirtual memoryVideo memoryBIOSRAM memory modules From the top: SIMM, DIMM and SODIMM
15Memory BasicsThe CPU accesses memory according to a distinct hierarchy. Whether it comes from permanent storage (the hard drive) or input (the keyboard), most data goes in random access memory (RAM) first. The CPU then stores pieces of data it will need to access, often in a cache, and maintains certain special instructions in the register.
16ROMRead-only memory (ROM), also known as firmware, is an integrated circuit programmed with specific data when it is manufactured. ROM chips are used not only in computers, but in most other electronic items as well.
18ROMSimilar to RAM, ROM chips contain a grid of columns and rows. But where the columns and rows intersect, ROM chips are fundamentally different from RAM chips. While RAM uses transistors to turn on or off access to a capacitor at each intersection, ROM uses a diode to connect the lines if the value is 1. If the value is 0, then the lines are not connected at all.
19PROMCreating ROM chips totally from scratch is time-consuming and very expensive in small quantities. For this reason, mainly, developers created a type of ROM known as programmable read-only memory (PROM). Blank PROM chips can be bought inexpensively and coded by anyone with a special tool called a programmer.
20EPROMErasable programmable read-only memory (EPROM) addresses this issue. EPROM chips can be rewritten many times. Erasing an EPROM requires a special tool that emits a certain frequency of ultraviolet (UV) light. EPROMs are configured using an EPROM programmer that provides voltage at specified levels depending on the type of EPROM used.
21EEPROMs and Flash Memory Electrically erasable programmable read-only memory (EEPROM) Though EPROMs are a big step up from PROMs in terms of reusability, they still require dedicated equipment and a labor-intensive process to remove and reinstall them each time a change is necessary. Also, changes cannot be made incrementally to an EPROM; the whole chip must be erased.Flash memory, a type of EEPROM that uses in-circuit wiring to erase by applying an electrical field to the entire chip or to predetermined sections of the chip called blocks. Flash memory works much faster than traditional EEPROMs because it writes data in chunks, usually 512 bytes in size, instead of 1 byte at a time.
22RAMRandom access memory (RAM) is the best known form of computer memory. RAM is considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell.The opposite of RAM is serial access memory (SAM). SAM stores data as a series of memory cells that can only be accessed sequentially (like a cassette tape).
23Common RAM TypesSRAM Static random access memory uses multiple transistors, typically four to six, for each memory cell but doesn't have a capacitor in each cell. It is used primarily for cache.DRAM Dynamic random access memory has memory cells with a paired transistor and capacitor requiring constant refreshing.FPMDRAM Fast page mode dynamic random access memory was the original form of DRAM. It waits through the entire process of locating a bit of data by column and row and then reading the bit before it starts on the next bit. Maximum transfer rate to L2 cache is approximately 176 MBps.
24EDODRAM Extended data-out dynamic random access memory does not wait for all of the processing of the first bit before continuing to the next one. As soon as the address of the first bit is located, EDO DRAM begins looking for the next bit. It is about five percent faster than FPM. Maximum transfer rate to L2 cache is approximately 264 MBps.SDRAM Synchronous dynamic random access memory takes advantage of the burst mode concept to greatly improve performance. The idea is that most of the time the data needed by the CPU will be in sequence. SDRAM is about five percent faster than EDO RAM and is the most common form in desktops today. Maximum transfer rate to L2 cache is approximately 528 MBps.
25DDRSDRAM Double data rate synchronous dynamic RAM is just like SDRAM except that is has higher bandwidth, meaning greater speed. Maximum transfer rate to L2 cache is approximately 1,064 MBps (for DDR SDRAM 133 MHZ).RDRAM Rambus dynamic random access memory is a radical departure from the previous DRAM architecture. Designed by Rambus, RDRAM uses a Rambus in-line memory module (RIMM), which is similar in size and pin configuration to a standard DIMM. What makes RDRAM so different is its use of a special high-speed data bus called the Rambus channel. RDRAM memory chips work in parallel to achieve a data rate of 800 MHz, or 1,600 MBps.
26Credit Card Memory Credit card memory is a proprietary self-contained DRAM memory module that plugs into a special slot for use in notebook computers.PCMCIA Memory Card Another self-contained DRAM module for notebooks, cards of this type are not proprietary and should work with any notebook computer whose system bus matches the memory card's configuration.
27CMOSRAM CMOS RAM is a term for the small amount of memory used by your computer and some other devices to remember things like hard disk settings. This memory uses a small battery to provide it with the power it needs to maintain the memory contents.VRAM VideoRAM, also known as multiport dynamic random access memory (MPDRAM), is a type of RAM used specifically for video adapters or 3-D accelerators. The "multiport" part comes from the fact that VRAM normally has two independent access ports instead of one, allowing the CPU and graphics processor to access the RAM simultaneously. VRAM is located on the graphics card and comes in a variety of formats, many of which are proprietary. The amount of VRAM is a determining factor in the resolution and color depth of the display.
28IDE ControllersIntegrated Drive Electronics (IDE) interface. Essentially, an IDE interface is a standard way for a storage device to connect to a computer. IDE is actually not the true technical name for the interface standard. The original name, AT Attachment (ATA), signified that the interface was initially developed for the IBM AT computer.A close-up of the primary and secondary IDE interfaces on a motherboard
29Cable KeyIDE devices use a ribbon cable to connect to each other. Ribbon cables have all of the wires laid flat next to each other instead of bunched or wrapped together in a bundle. IDE ribbon cables have either 40 or 80 wires. There is a connector at each end of the cable and another one about two-thirds of the distance from the motherboard connector.
30USB PortsJust about any computer that you buy today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy, too.
31Sample List of USB Devices PrintersScannersMiceJoysticksDigital camerasWebcamsModemsSpeakersTelephonesNetwork connectionsThe rectangular socket is a typical USB socket on the back of a PC
32The USB standard uses "A" and "B" connectors to avoid confusion: "A" connectors head "upstream" toward the computer."B" connectors head "downstream" and connect to individual devices.
33Serial PortsConsidered to be one of the most basic external connections to a computer, the serial port has been an integral part of most computers.Serial ports provide a standard connector and protocol to let you attach devices, such as modems, to your computer.
359-pin connector:1. Carrier Detect - Determines if the modem is connected to a working phone line.2. Receive Data - Computer receives information sent from the modem.3. Transmit Data - Computer sends information to the modem.4. Data Terminal Ready - Computer tells the modem that it is ready to talk.5. Signal Ground - Pin is grounded.6. Data Set Ready - Modem tells the computer that it is ready to talk.7. Request To Send - Computer asks the modem if it can send information.8. Clear To Send - Modem tells the computer that it can send information.9. Ring Indicator - Once a call has been placed, computer acknowledges signal (sent from modem) that a ring is detected.
3625-pin connector: 1. Not Used 2. Transmit Data - Computer sends information to the modem.3. Receive Data - Computer receives information sent from the modem.4. Request To Send - Computer asks the modem if it can send information.5. Clear To Send - Modem tells the computer that it can send information.6. Data Set Ready - Modem tells the computer that it is ready to talk.7. Signal Ground - Pin is grounded.
3725-pin connector:8. Received Line Signal Detector - Determines if the modem is connected to a working phone line.9. Not Used: Transmit Current Loop Return (+)10. Not Used11. Not Used: Transmit Current Loop Data (-)12. Not Used13. Not Used14. Not Used15. Not Used16. Not Used17. Not Used18. Not Used: Receive Current Loop Data (+)
3825-pin connector: 19. Not Used 20. Data Terminal Ready - Computer tells the modem that it is ready to talk.21. Not Used22. Ring Indicator - Once a call has been placed, computer acknowledges signal (sent from modem) that a ring is detected.23. Not Used24. Not Used25. Not Used: Receive Current Loop Return (-)A dual serial port card
39A typical parallel port on the back of your computer Parallel PortsParallel ports were originally developed by IBM as a way to connect a printer to your PC. When IBM was in the process of designing the PC, the company wanted the computer to work with printers offered by Centronics, a top printer manufacturer at the time.A typical parallel port on the back of your computer
40Parallel ports can be used to connect a host of popular computer peripherals: PrintersScannersCD burnersExternal hard drivesIomega Zip removable drivesNetwork adapters
41SCSI devices usually connect to a controller card like this one Most home and small-office PCs use an IDE hard drive and have a PCI bus for adding components to the computer. But a lot of computers, particularly high-end workstations and older Apple Macintoshes, use the Small Computer System Interface (SCSI) bus to connect components, which may include:Hard drivesScannersCD-ROM/RW drivesPrintersSCSI devices usually connect to a controller card like this one
42Kinds of SCSI Connectors Internal SCSI devices connect to a 50-pin ribbon cableDB-25 SCSI connector
43Kinds of SCSI Connectors 68-pin Alternative 3 SCSI connector50-pin Centronics SCSI connector
44Kinds of SCSI Connectors External SCSI devices connect using thick, round cablesInternal SCSI devices connect to a ribbon cable
46Hard DisksHard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes. They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product).
47Capacity and Performance There are two ways to measure the performance of a hard disk:Data rate - The data rate is the number of bytes per second that the drive can deliver to the CPU. Rates between 5 and 40 megabytes per second are common.Seek time - The seek time is the amount of time between when the CPU requests a file and when the first byte of the file is sent to the CPU. Times between 10 and 20 milliseconds are common.The other important parameter is the capacity of the drive, which is the number of bytes it can hold.
48Inside: Electronics Board It is a sealed aluminum box with controller electronics attached to one side. The electronics control the read/write mechanism and the motor that spins the platters.
49Inside: Beneath the Board Underneath the board are the connections for the motor that spins the platters, as well as a highly-filtered vent hole that lets internal and external air pressures equalize:
50Inside: Platters and Heads In order to increase the amount of information the drive can store, most hard disks have multiple platters. This drive has three platters and six read/write heads:
51Storing the DataData is stored on the surface of a platter in sectors and tracks. Tracks are concentric circles, and sectors are pie-shaped wedges on a trackA typical track is shown in yellow; a typical sector is shown in blue. A sector contains a fixed number of bytes -- for example, 256 or 512. Either at the drive or the operating system level, sectors are often grouped together into clusters.
52Floppy Disk DrivesThe floppy disk drive (FDD) was the primary means of adding data to a computer until the CD-ROM drive became popular.Basically, a floppy disk drive reads and writes data to a small, circular piece of metal-coated plastic similar to audio cassette tape.
53The major parts of a FDD include: Read/Write HeadsDrive MotorStepper MotorMechanical FrameCircuit Board
54PC Power SuppliesIn a personal computer (PC), the power supply is the metal box usually found in a corner of the case. The power supply is visible from the back of many systems because it contains the power-cord receptacle and the cooling fan.
55Power Supply Wattage PC Item Watts Accelerated Graphics Port (AGP) card20 to 30WPeripheral Component Interconnect (PCI) card5Wsmall computer system interface (SCSI) PCI card20 to 25Wfloppy disk drivenetwork interface card4W50X CD-ROM drive10 to 25WRAM10W per 128M5200 RPM Integrated Drive Electronics (IDE) hard disk drive5 to 11W7200 RPM IDE hard disk drive5 to 15WMotherboard (without CPU or RAM)550 MHz Pentium III30W733 MHz Pentium III23.5W300 MHz Celeron18W600 MHz Athlon45W
56This Microsoft Intellimouse uses optical technology Computer MiceA pointing device used to select various options.This Microsoft Intellimouse uses optical technology
57Inside a MouseA ball inside the mouse touches the desktop and rolls when the mouse moves.Two rollers inside the mouse touch the ball. One of the rollers is oriented so that it detects motion in the X direction, and the other is oriented 90 degrees to the first roller so it detects motion in the Y direction. When the ball rotates, one or both of these rollers rotate as well.
58Inside a MouseThe rollers each connect to a shaft, and the shaft spins a disk with holes in it. When a roller rolls, its shaft and disk spin.An on-board processor chip reads the pulses from the infrared sensors and turns them into binary data that the computer can understand.
59Inside a MouseOn either side of the disk there is an infrared LED and an infrared sensor. The holes in the disk break the beam of light coming from the LED so that the infrared sensor sees pulses of light. The rate of the pulsing is directly related to the speed of the mouse and the distance it travels.
60Data InterfaceMost mice in use today use the standard PS/2 type connector.These pins have the following functions1. Unused2. +5 volts (to power the chip and LEDs)3. Unused4. Clock5. Ground6. DataA typical PS/2 connector: Assume that pin 1 is located just to the left of the black alignment pin, and the others are numbered clockwise from there.
61Computer KeyboardsThe part of the computer that we come into most contact with is probably the piece that we think about the least. But the keyboard is an amazing piece of technology.An Apple Extended keyboard
62Types of Keyboards 101-key Enhanced keyboard 104-key Windows keyboard 82-key Apple standard keyboard108-key Apple Extended keyboard
63microprocessor and controller circuitry of a keyboard Inside the Keyboardrubber dome switchesmicroprocessor and controller circuitry of a keyboardkey matrixrubber dome
65BIOSOne of the most common uses of Flash memory is for the basic input/output system of your computer, commonly known as the BIOS (pronounced "bye-ose"). On virtually every computer available, the BIOS makes sure all the other chips, hard drives, ports and CPU function together.The BIOS is special software that interfaces the major hardware components of your computer with the operating system. It is usually stored on a Flash memory chip on the motherboard, but sometimes the chip is another type of ROM.
66What BIOS DoesWhen you turn on your computer, the BIOS does several things. This is its usual sequence:1. Check the CMOS Setup for custom settings2. Load the interrupt handlers and device drivers3. Initialize registers and power management4. Perform the power-on self-test (POST)5. Display system settings6. Determine which devices are bootable7. Initiate the bootstrap sequence
67Configuring BIOSTo enter the CMOS Setup, you must press a certain key or combination of keys during the initial startup sequence. Most systems use "Esc," "Del," "F1," "F2," "Ctrl-Esc" or "Ctrl-Alt-Esc" to enter setup.Once you have entered setup, you will see a set of text screens with a number of options.
68Common options include: System Time/Date - Set the system time and dateBoot Sequence - The order that BIOS will try to load the operating systemPlug and Play - A standard for auto-detecting connected devices; should be set to "Yes" if your computer and operating system both support itCMOS Setup
69Common options include: Mouse/Keyboard - "Enable Num Lock," "Enable the Keyboard," "Auto-Detect Mouse"...Drive Configuration - Configure hard drives, CD-ROM and floppy drivesMemory - Direct the BIOS to shadow to a specific memory addressSecurity - Set a password for accessing the computerPower Management - Select whether to use power management, as well as set the amount of time for standby and suspendExit - Save your changes, discard your changes or restore default settings
71Preventive Maintenance Cleaning of Computer, Keyboard and PrinterCleaning of Pointing DeviceTaking care of ComputerTo take care of your CD’s
72Cleaning of Computer, Keyboard and Printer Turn off the computer and unplug the power cordUse soft cloth moistened with water an gently wipe the exterior of the computer, keyboard and printer.
73Cleaning of Pointing Device Open the circular cover underneath the mouseTake out the rubber ball and wipe it with a soft, damp clothPut the ball and close the cover
74Taking care of Computer Do not expose the computer to direct sunlightDo not subject the computer to magnetic fieldsDo not expose the computer to dust and dirtNever place the system on uneven surfaces
75To take care of your CD’s Keep your disc in its case when not in use to avoid scratches or other damage.When cleaning disc, use a clean, dust free cloth and wipe in a straight line from the center to the edge.Clean your CD drive periodically.
87Operating SystemsThe operating system defines our computing experience. It's the first software we see when we turn on the computer, and the last software we see when the computer is turned off.It's the software that enables all the programs we use.
88At the simplest level, an operating system does two things: It manages the hardware and software resources of the computer system. These resources include such things as the processor, memory, disk space, etc.It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.
89The operating system's tasks, in the most general sense, fall into six categories: Processor managementMemory managementDevice managementStorage managementApplication interfaceUser interface
91AGPAccelerated Graphics Port AGP and AGP graphics cards are now the standard for processing graphics on computers. Like all hardware, the technology and specifications are constantly improving.
92Computer Monitors An output device that displays information. Often referred to as a monitor when packaged in a separate case, the display is the most-used output device on a computer. The display provides instant feedback by showing you text and graphic images as you work or play.
93number of colors different bit depths 12 (monochrome)24 (CGA)416 (EGA)8256 (VGA)1665,536 (High Color, XGA)2416,777,216 (True Color, SVGA)3216,777,216 (True Color + Alpha Channel)Sony flat-panel display
94Industry Standard Architecture 16-bit sound card Sound CardsThe voice in your computer that lets you know when you've received a new is made possible by the sound card. Before the arrival of sound cards, personal computers (PCs) were limited to beeps from a tiny speaker on the motherboard.In 1989, Creative Labs introduced the Creative Labs SoundBlaster® card.Industry Standard Architecture 16-bit sound card
95Anatomy of a Sound Card A typical sound card has: a digital signal processor (DSP) that handles most computationsa digital to analog converter (DAC) for audio leaving the computeran analog-to-digital converter (ADC) for audio coming into the computer
96Anatomy of a Sound Cardread-only memory (ROM) or Flash memory for storing datamusical instrument digital interface (MIDI) for connecting to external music equipment (for many cards, the game port is also used to connect an external MIDI adapter)jacks for connecting speakers and microphones, as well as line in and line outa game port for connecting a joystick or gamepad
97Sound cards may be connected to: headphonesamplified speakersan analog input sourcemicrophoneradiotape deckCD playera digital input sourcedigital audiotape (DAT)CD-ROM drivean analog output device - tape decka digital output deviceDATCD recordable (CD-R)
98ModemsThe word "modem" is a contraction of the words modulator-demodulator. A modem is typically used to send digital data over a phone line.
99Modem Speeds 300 bps - 1960s through 1983 or so 1200 bps - Gained popularity in 1984 and 19852400 bps9600 bps - First appeared in late 1990 and early 199119.2 kilobits per second (Kbps)28.8 Kbps33.6 Kbps56 Kbps - Became the standard in 1998ADSL, with theoretical maximum of up to 8 megabits per second (Mbps) - Gained popularity in 1999
100CD BurnersAn external writable CD drive, also called a CD burner: With this type of drive, you can take music or data files from your computer and make your own CDs.Today, writable CD drives (CD burners) are standard equipment in new PCs, and more and more audio enthusiasts are adding separate CD burners to their stereo systems.
101Laser AssemblyThe CD burner has a moving laser assembly, just like an ordinary CD player. But in addition to the standard "read laser," it has a "write laser." The write laser is more powerful than the read laser, so it interacts with the disc differently.The laser assembly inside a CD burner
102ScannersScanners have become an important part of the home office over the last few years. Scanner technology is everywhere and used in many ways:Flatbed scannersSheet-fed scannersHandheld scannersDrum scanners
103Parts of a typical flatbed scanner include: Charge-coupled device (CCD) arrayMirrorsScan headGlass plateLampLensCoverFiltersStepper motorStabilizer barBeltPower supplyInterface port(s)Control circuitry
104There are three common connections used by scanners: ParallelSmall Computer System Interface (SCSI)Universal Serial Bus (USB)
105Digital CamerasThe digital camera is one of the most remarkable instances of this shift because it is so truly different from its predecessor.All digital cameras have a built-in computer, and all of them record images in an entirely electronic form.
106Some typical resolutions that you find in digital cameras 256x256 pixels640x480 pixels1216x912 pixels1600x1200 pixelsImage CapacityImage SizeTIFF (uncompressed)JPEG (high quality)JPEG (medium quality)640x4801.0 MB300 KB90 KB800x6001.5 MB500 KB130 KB1024x7682.5 MB800 KB200 KB1600x12006.0 MB1.7 MB420 KB
107number of storage systems currently used in digital cameras Built-in memory - Some extremely inexpensive cameras have built-in Flash memory.SmartMedia cards - SmartMedia cards are small Flash memory modules.CompactFlash - CompactFlash cards are another form of Flash memory, similar to but slightly larger than SmartMedia cards.Memory Stick - Memory Stick is a proprietary form of Flash memory used by Sony.Floppy disk - Some cameras store images directly onto floppy disks.Hard disk - Some higher-end cameras use small built-in hard disks, or PCMCIA hard-disk cards, for image storage.Writeable CD and DVD - Some of the newest cameras are using writeable CD and DVD drives to store images.
108Inkjet PrintersAn inkjet printer is any printer that places extremely small droplets of ink onto paper to create an image.
109Impact vs. Non-impactThere are several major printer technologies available. These technologies can be broken down into two main categories with several types in each:Impact - These printers have a mechanism that touches the paper in order to create an image.Non-impact - These printers do not touch the paper when creating an image.
110There are two main impact technologies: Dot matrix printers use a series of small pins to strike a ribbon coated with ink, causing the ink to transfer to the paper at the point of impact.Character printers are basically computerized typewriters. They have a ball or series of bars with actual characters (letters and numbers) embossed on the surface.
111Non-impact technologies: Laser printers, covered in-depth in use dry ink (toner), static electricity, and heat to place and bond the ink onto the paper.Inkjet printers, which are described in this article, use a series of nozzles to spray drops of ink directly on the paper.Solid ink printers contain sticks of wax-like ink that are melted and applied to the paper.Dye-sublimation printers have a long roll of transparent film that resembles sheets of red-, blue-, yellow- and gray-colored cellophane stuck together end to end.
112Non-impact technologies: Thermal wax printers are something of a hybrid of dye-sublimation and solid ink technologies. They use a ribbon with alternating CMYK color bands.Thermal autochrome printers have the color in the paper instead of in the printer. There are three layers (cyan, magenta and yellow) in the paper, and each layer is activated by the application of a specific amount of heat.
113Inside an Inkjet Printer 1. Print head assemblyPrint headInk cartridgesPrint head stepper motorBeltStabilizer bar
114Inside an Inkjet Printer 2. Paper feed assemblyPaper tray/feederRollersPaper feed stepper motor
115Inside an Inkjet Printer 3. Power supply4. Control circuitry5. Interface port(s)
117Application Software Installation MS – Office 97MS – Office 2000MS – Office XP
118MS - DOS Basics Format Command Directory Command DIR Command EDIT CommandCOPY CommandPATH CommandREN CommandATTRIB CommandDEL CommandCHKDSK Command
119MS - DOS Basics a. C:> FORMAT A: b. C:> FORMAT A:/S Format CommandPrepares a diskette for use or wipesout all data from the disk.a. C:> FORMAT A:b. C:> FORMAT A:/Sc. C:> FORMAT A:/Vd. C:> FORMAT A:/S/V/Q
120MS - DOS Basics C:> DIR C:> DIR / P C:> DIR / W Displays the contents of a diskor a directory.DIR CommandC:> DIRC:> DIR / PC:> DIR / WC:> DIR / P / WC:> DIR / BC:> DIR / L
121MS - DOS Basics Syntax: C:> COPY <source> <destination> COPY CommandCopies a file or a group of filesfrom one disk to another or fromone directory to another.Syntax: C:> COPY <source> <destination>
122Syntax: C:> REN <old filename> <new filename> MS - DOS BasicsREN CommandRenames file or a group offiles.Syntax: C:> REN <old filename> <new filename>
123C:> DEL <filename> MS - DOS BasicsDEL CommandDeletes or erases a file or agroup of files from disk or adirectory.C:> DEL <filename>
124MS - DOS Basics Directory Command MD –creates a directory CD –changes current / working directoryRD –removes a directoryCD\ - makes root directory as the current directoryCD. –change to current directoryCD.. –change to parent directory
126MS - DOS Basics To display the current path C:>\ PATH PATH CommandSets the path for the commandand files.To display the current pathC:>\ PATHb. To set the pathC:>\ PATH =C:>\<dirname1>; C:\<dirname2>
127MS - DOS Basics ATTRIB Command To display the attributes of a file Display or changes the attributesof a file or group of files.To display the attributes of a fileC:>\attrib <filename>b. To unprotect a file in DOSC:>\attrib –r a:<filename>c. To make a file hiddenC:>\attrib +h a:<filename>d. To remove the hidden attribute of a fileC:>\attrib –h a:<filename>
128MS - DOS Basics To display only the status of a disk CHKDSK CommandDisplay the contents of a disk,including hidden files; displaysalso the status of a disk.To display only the status of a diskC:>\CHKDSK A:>b. To display the status and the contents ofdisk including the filesC:>\CHKDSK A:/V
130Local Area Network (LAN) An Ethernet card, on the other hand, connects directly to the computer's bus. Ethernet cards come in two flavors: one that accepts 10 Mbps, and another that accepts 100 Mbps.
131Why Network?Networking allows one computer to send information to and receive information from another. Certainly the Internet is the most conspicuous example of computer networking, linking millions of computers around the world, but smaller networks play a roll in information access on a daily basis.
132Local Area vs. Wide AreaLocal area network (LAN) technologies connect many devices that are relatively close to each other, usually in the same building. The library terminals that display book information would connect over a local area network.Wide area network (WAN) technologies connect a smaller number of devices that can be many kilometers apart.
133The EthernetIn 1973, at Xerox Corporation’s Palo Alto Research Center (more commonly known as PARC), researcher Bob Metcalfe designed and tested the first Ethernet network. While working on a way to link Xerox’s "Alto" computer to a printer, Metcalfe developed the physical method of cabling that connected devices on the Ethernet as well as the standards that governed communication on the cable.
134Ethernet BasicsEthernet is a local area technology, with networks traditionally operating within a single building, connecting devices in close proximity.Ethernet devices could have only a few hundred meters of cable between them, making it impractical to connect geographically dispersed locations.Modern advancements have increased these distances considerably, allowing Ethernet networks to span tens of kilometers.
135Ethernet TerminologyMedium - Ethernet devices attach to a common medium that provides a path along which the electronic signals will travel. Historically, this medium has been coaxial copper cable, but today it is more commonly a twisted pair or fiber optic cabling.
136Ethernet TerminologySegment - We refer to a single shared medium as an Ethernet segment.Node - Devices that attach to that segment are stations or nodes.Frame - The nodes communicate in short messages called frames, which are variably sized chunks of information.
138BridgesTo alleviate problems with segmentation, Ethernet networks implemented bridges. Bridges connect two or more network segments, increasing the network diameter as a repeater does, but bridges also help regulate traffic.
139Switched EthernetModern Ethernet implementations often look nothing like their historical counterparts. Where long runs of coaxial cable provided attachments for multiple stations in legacy Ethernet, modern Ethernet networks use twisted pair wiring or fiber optics to connect stations in a radial pattern.
141Alternative Network Technologies: Token Ring The most common local area network alternative to Ethernet is a network technology developed by IBM, called token ring. Where Ethernet relies on the random gaps between transmissions to regulate access to the medium, token ring implements a strict, orderly access method.
143Illustration of a Cisco Catalyst switch LAN SwitchesSwitches are a fundamental part of most networks. They make it possible for several users to send information over a network at the same time without slowing each other down.Illustration of a Cisco Catalyst switch