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GENERAL INFORMATION

  • The CPU processes all communication among the various components of the PC. The IBM introduced the MCA architecture in both the 16-bit and the 32-bit versions. System Interface (SCSI or Scuzzy) allows up to seven intelligent devices to connect to it in parallel format. The devices are daisy-chained together using a straight ribbon 50-pin connector (Macintosh requires a 25-pin D-shell connector).

  • Avoid placing electronic components in or on non-conductive surfaces.

  • RAM & CMOS chips are especially vulnerable. ESD damage is non-recoverable; it is lethal.

  • Always transport sensitive adapter cards and components in their anti-static containers.

  • To protect against ESD, place the computer on a grounded anti-static mat and wear an ESD grounding wrist strap. This puts you and the PC at the same electrical charge potential.

  • Using the wrist strap and a known common ground will assure you and the PC are at the same electrical potential.

  • The threat from ESD damage can be minimized by keeping humidity above 70° and using a wrist strap when working with static sensitive devices.

  • The typical ESD wrist strap is composed of a detachable strap connected to a wire with a metallic clip. Located between the clip and the strap is a small resistor to control the discharge to ground.

  • The symbol indicates ground.

  • A 14.4 modem will transmit at about 14,000 bits per second.

  • The EPA has established strict guidelines concerning the disposal of batteries.

  • Each daisy-chained device requires a unique address (or ID).

  • The DOS (MSCDEX.EXE) command provides access to CD-ROM drives. It is usually located in the MS-DOS directory.

  • The typical PC Power Supply output voltages are +12, -12, +5 and -5 volts. A positive 5 volts is the voltage used by the PC circuitry.

  • While the main function of the CPU is to process program instructions, it is also responsible for Math functions and controlling the IO operations of the PC.

  • Care should be taken when storing paper intended for use in a laser printer or copier. The physical location, temperature and humidity all could affect its functionality in the machine.

  • The SCSI interface will support either external CD-ROMs or external hard drives. Bad power will sometimes generate a parity error, however, a majority of the time it will be caused by defective RAM. The two most common commands in the config.sys file are the "Buffers=" and the "Files=" statements.

  • The MS-DOS SHARE Program installs file sharing and locking capabilities on your hard disks. DOSKEY is a memory resident program that will recall MS-DOS commands. It is typically loaded in the autoexec.bat file

  • Accessing data or programs from RAM is 100-300 times faster than from mechanical devices like floppies, CDs and hard disks.

  • The host adapter always receives the highest priority address (7) and the bootable drive should be addressed as zero (0). Each SCSI device requires a unique address. When installing a new device it should be assigned an unused SCSI address. CGA= 640 X 200
    EGA= 640 X 350
    HGC= 720 X 350
    VGA= 640 X 480
    MCGA= 640 X 480
    SVGA= 800 X 600


  • When files are no longer stored in consecutive locations on the disk, performance is degraded. This is called fragmentation.

  • The MS-DOS MEM command displays the amount of used and free memory on your computer.

  • The physical size and location of the power supply on/off switch along with the voltage ratings should all be considered when replacing or upgrading. The center connector on the AC outlet will usually provide adequate ground connection.

  • A defective power supply or bad video card could both cause a blank computer screen.

  • The himem.sys command must be loaded before emm386.exe in the config.sys file.

  • The mode command can be used to change LPT and COM port settings.

  • An Uninterruptible Power Supply (UPS) can be used to ensure that power is not lost to mission critical devices.

  • ESD is most likely to occur in a low humidity environment.

  • The OHMs scale should be used to check continuity.

  • The /C (classify) option of the MEM command will display the TSRs currently running on your PC.

  • The EMM386.EXE command manages and makes available expanded memory.

  • (PCMCIA) Personal Computer Memory card Industry Association. This acronym is now simply referred to as PC Card Bus.

  • An icon's properties will display the path of the working directory.

  • Static (ESD) will destroy components and it's not recoverable, while EMI is a recoverable event.

  • The files and buffers statements are contained in the config.sys file located in the root directory.

  • When storing older 5¼ diskettes, it is very important to store them in their protective sleeves.

  • IRQ 1 is used by the computer's keyboard.

  • The laser printer drum is coated with a light sensitive material.

  • Every SCSI device must have a unique SCSI ID number from 0 - 7.

  • Your first step should be to notice any error messages on the screen.

  • These are all good questions to ask to help solve a client's problem.

  • Establish the habit of checking product for any physical damage after unboxing.

  • Important computer boot information is stored in the ROM BIOS.

  • After completing a successful POST, you should hear one beep.

  • Serial and parallel ports are interfaces that allow bi-directional movement of data. (They send and receive information). The power.exe program located in the DOS directory was designed to save the battery on lap top computers when sitting idle.

  • Maintaining polarity when measuring AC voltage is not important but is crucial when measuring DC voltage.

  • A modem is typically attached to a serial port, sometimes referred to as an ASYNC communications port.

  • A SCSI host bus adapter can be used as either an input or output device.

  • To measure AC ripple you need to set the meter to the AC voltage scale.

  • You can use a multimeter to test resistors, capacitors, diodes, transistors and for measuring both AC and DC voltages. Multimeters are not suited for testing digital logic circuits.

  • Serial and parallel ports are peripheral ports. Serial ports (like the RS-323 used for modems) channel data one bit at a time. Parallel ports move data at much higher speeds in 8-bit clumps along parallel lines.

  • When installing expansion boards like internal modems or video cards, you should take steps to avoid static discharge.

  • The carrier detect and the receive data signal must be present.

  • 2F8 & 3F8 are used by the serial ports COM1 and COM 2. 378 is used by LPT1.

  • False. You would need to use a high voltage probe.

  • HDI basically indicates a hard disk crash, usually manifesting itself as a grinding noise with the head coming in contact with the disk. Thus, Head to Disk Interference.

  • COM 1 - 9 pin male port
    COM 2 - 25 pin male port
    LPT 1 - 25 pin female port


  • A printer can be attached to any serial or parallel port in the computer.

  • The parallel printer port on a PC is usually a 25-pin female connector. Serial ports can be identified by a 9- or 25-pin connector. Serial port communication is controlled by 3 chips: the UART series (8250, 16450, and 16550) and two driver chips (1488 and 1489).

  • Interrupt Request Lines (IRQs or interrupts) allow boards and peripherals to interrupt the CPU and request service. Each board or peripheral device communicates through a specific and unique IRQ. Initially (XT Class computers), used 8-bit ISA Buses that provided 8 levels of standard interrupts. AT computers introduced the 16-bit Bus. 0 Timer
    1 Keyboard
    2 Cascade
    3 Com2, Com4
    4 Com1, Com3
    5 LPT2
    6 Floppy drive controller
    7 LPT1
    8 Clock
    9 Redirected IRQ2
    10-12 (depends on machine)
    13 Coprocessor
    14 Hard disk
    15 Available


  • Laser toner cartridges can be used and rebuilt by a number of different vendors; however, they should only be recycled once.

  • The conductor with the stripe connects to pin 1 of the connector.

  • Field Replaceable Units (FRUs) can be readily replaced in the field on a service call. No soldering or special equipment is required to replace them.

  • PCMCIA cards come in various sizes: Type 1 -- 3.5 millimeters
    Type 2 -- 5.0 millimeters
    Type 3 -- 10.5 millimeters


  • In the CONFIG.SYS file, the MOUSE.SYS driver controls the mouse. In the AUTOEXEC.BAT file, the MOUSE.BAT driver controls the mouse.

  • PCI is unique because it is a 64-bit bus. PCI supports data paths for the newer Pentium computers.

  • The RS-232 Standard defines the pinouts on a typical 25-pin male D connector as: Pin1 Frame ground
    Pin2 (TDZ) Transmit Data
    Pin3 (RD) Receive Data
    Pin4 (RTS) Request to Send
    Pin5 (CTS) Clear to Send
    Pin 6 (DSR) Data Set Ready
    Pin7 (SG) Signal Ground
    Pin8 (DCD) Data Carrier Detect
    Pin 20 (DTR) Data Term Ready


  • TSR stands for Terminate and Stay Resident. TSR programs stay in memory when they are not presently being executed (e.g., a memory resident utility). When troubleshooting a PC, always boot with a clean configuration - with no memory managers or TSR programs.

  • To remove the danger of a virus writing to your executable files, make them READ ONLY by assigning the "r" attribute with the DOS ATTRIB command.

  • SMARTDRV.EXE can cache floppy drives, hard drives, and CD-ROM drives. It CANNOT cache compressed hard drives, network drives, tape systems, or video devices.

  • (CMOS) Complementary Metal Oxide Semi-conductor, the CMOS chip holds the computer's configuration information, i.e. hard disk type, size, types of floppies and installed memory.

  • Before a hard disk can be formatted, it must be partitioned into logical disk drives. Each logical disk drive is identified with a different letter of the alphabet. A and B are reserved for the floppy drives and C for the first primary hard drive. D is reserved for the first extended partition.

  • The basic steps for formatting a hard disk are: Low-level Format
    Partition
    High-level Format (DOS)


  • A CPU internal speed is typically 2 to 3 times FASTER than the external bus speed. Thus, an internal core logic at 50 MHz would most likely have an external logic running at 25 MHz.

  • When configuring and changing modem settings, the defaults can be re-established by using the ATZ command.

  • Extended Memory starts at 1MB or 1024KB. The HMA memory is located in the first 64K of the Extended Memory.

  • To load DOS in the HMA, include the DOS=HIGH command in the CONFIG.SYS file.

  • Retrieving data from RAM (Random Access Memory) is approximately 100 times faster than retrieving data stored on mechanical or optical devices.

  • The process of copying part of the ROM contents into extended memory will improve overall performance.

  • The SYSTEM.INI file contains configuration information for hardware drivers used by Windows. Parameters may be modified by running SETUP, Windows Setup, or through the control panel.

  • Program Information Files (PIFs) define requirements for DOS applications in Windows and lets Windows run them. Windows uses the APPS.INF file to identify DOS applications, list them, and suggest PIF settings.

  • To run Windows in either the Standard or Enhanced Mode, an XMS (Extended Memory) driver, such as HIMEM.SYS, must be loaded.

  • WIN.INI and SYSTEM.INI are critical files that must be backed up after installation and saved before Windows is reinstalled. All files with the .GRP extension should also be saved and backed up.

  • Hard Drive-a mass storage device which records data in a circular fashion on tracks which are broken into sectors. Multiple sectors make up clusters.

  • The minimum memory requirement for Windows 3.1 is 2 MB. Minimum memory for Windows 3.11 WFW is 4 MB; Windows95 is 8 MB; NT Workstation is 12 MB; and NT Server is 16 MB.

  • WIN.INI controls Windows environmental settings. SYSTEM.INI contains system hardware settings information.
    CONTROL.INI contains color schemes, patterns, printer settings, etc.


  • In Windows, an icon is used to represent a file, program, or utility. An icon may exist multiple times in multiple program groups.

  • The Notepad utility in Windows saves files in ASCII format. The Write program saves files with a .WRI extension.

  • Starting DOS -
    POST runs.
    ROM BIOS (Basic Input/ Output System) chips are read to activate the boot.
    The boot program looks for the operating system file on A drive first, then C drive.
    IO.SYS is loaded.
    MS-DOS.SYS is loaded.
    CONFIG.SYS is read.
    COMMAND.COM (command processor for DOS) is loaded.
    Lastly, AUTOEXEC.BAT is loaded and the user sees the Command Prompt.


  • If mistakes exist in either the CONFIG.SYS or AUTOEXEC.BAT, the system may freeze. To bypass these files, press F5 when Starting DOS. . . appears on screen. To step through each command, one at a time, you can press the F8 key.

  • Access speed-the time it takes to locate data on a hard drive.

  • Transfer rate-how fast the data transfers from the hard disk to the CPU.

  • To create a bootable floppy disk, first format it with format a: /s. Then enter SYS A: or SYS C: A: The first command will erase all other files on the disk, the second will not.

  • Six Steps of Laser Printing Cleaning - residual toner is scraped from the photosensitive drum. Conditioning - the drum receives a uniform negative charge which it can only maintain in a dark environment. Writing - a laser beam dots the drum, creating a positively charged image. Developing - negatively charged toner adheres to the drum where it has been dotted by the laser. Transferring - the corona wire (transfer roller) charges paper with a positive charge, enabling the paper to pick up the toner as it passes between the drum and the corona wire. Fusing - fuser rollers melt the toner while pressure rollers press the toner into the paper.

  • The Fuser Roller, the drum and sheet feeders all physically come into contact with the paper. The scanner is not part of the paper path.

  • The ozone filter requires vacuuming during preventive maintenance.

  • A fuser pad installed against the fuser roller helps keep it lubricated so that residual toner will not adhere to it.

  • Improper ribbon advancement will cause light/ dark print. An old ribbon will cause patchy, faint, uneven or intermittent print.

  • A dry or defective ribbon will cause faint or uneven print.

  • A good troubleshooting model should always start with the obvious quick-fix solutions first, i.e. is the printer on-line, plugged in, etc.

  • Prevention maintenance on a hard disk includes: disk check diagnostics, surge protection, parking the heads, and using a disk-caching program.

  • Use a clean, lint free cloth and mild, soapy water to clean plastic cases. This will prevent damaging the plastic.

  • Cleaning special CRT screens should always be done with non-abrasive cleaners to avoid damage to the coatings on the screens.

  • The hard drive stores data magnetically and should be kept away from any magnetic fields. Extreme hot and cold can also cause the areas between the tracks to expand and/or contract.

  • Spike - a short over-voltage condition in the power supply. Surge - an extended over-voltage condition. Surge Protectors/ Suppressers - made to protect against over-voltage, but provide little more than an extension plug. Stand-by Power Supplies (SPS) -provide battery power during power sags, but are not directly connected to the computer and require valuable switch time to kick in. Uninterruptible Power Supply (UPS) - an auxiliary battery power supply directly connected to the computer, requiring no switch time.

  • Power cannot enter the PC if the AC power cable has been disconnected. Simply turning off the AC power does not provide the same insurance.

  • When troubleshooting a monitor, always begin with the obvious (e.g., is the monitor turned on, has the contrast been turned down). To test whether the monitor is getting high voltage, place a sheet of paper against a blank screen. If the paper sticks, the screen surface has high voltage static. Finally, re-boot the computer and listen for POST beeps.

  • A monitor (or CRT) can hold a charge even after it has been unplugged. Always unplug a CRT (Cathode Ray Tube) before discharging it and discharge it before working on it.

  • Integrated Device Electronics (IDE or AT Attachment) was the first interface to embed the controllers in the drive housing. IDE drives have a transfer rate of 4 MBps. Two drives can be supported on the same cable if one is configured as Master and the other as Slave.

  • Always check for the obvious first. Are the cables attached, is it turned on, or has the brightness adjustment been turned down?

  • The key to answering this question is the word "performance." VGA offers the highest level of performance. If the key word was "resolution," the answer would be SVGA.

  • When checking for continuity, the OHMS setting should be used and the meter should read (0) for a good circuit.

  • Always start the meter on the HIGHEST voltage setting to prevent damage to the meter.

  • You will always read (0.00) while measuring a good fuse.

  • A good computer speaker will always indicate a direct short and display 0 OHMs.

  • Always start the meter on the HIGHEST voltage setting to prevent damage to the meter.

  • You will always read (0.00) while measuring a good fuse.

  • The POST verifies that contiguous memory as well as communication ports and display adapters are installed.

  • The POST counts all the contiguous memory installed on the system board.

  • A good technique for troubleshooting batch files is to include PAUSE commands in the file to suspend processing long enough to read any error messages.

  • The SCSI hard drives have the fastest transfer rate at 5 MBps, giving it the fastest access to large video files.

  • During the boot process, the microcomputer performs a Power On Self Test (POST) that first counts and checks memory from the system board (a.k.a., the planar or motherboard).

  • Files with hidden attributes can be found by using the DIR command with the /A option.

  • System BIOS often needs to be upgraded for an IDE drive to function.

  • To install an Enhanced IDE drive, you would also have to replace the controller board, sometimes referred to as a paddle board.

  • A faulty floppy drive ribbon cable will often cause a computer to display "phantom directories" (directories that do not exist on the diskette currently inserted in the computer). Pin #34 detects changes when the diskette is changed.

  • FRUs, typically defined by the manufacturer, are replaced in a recommended sequence as defined in the troubleshooting flow supplied with the product.

  • Program performance and disk reads can be enhanced by adding extra RAM and using disk and file caching. A continuously blinking light reveals a need to increase RAM.

  • Because of the multiple components found within it, the monitor emits radiation.


    HARDWARE

  • A modem is the most common type of hardware to interface with a serial port. It enables computers to communicate over standard telephone lines. Modems take the incoming analog data signals from the telephone lines and convert it to a digital format that the computer understands.

  • Information or software programs stored on a non-volatile chip is called firmware. The non-volatile nature of the chip ensures that the information stored within the chip will not be lost after power is removed.

  • The PC boot process starts when a small program within the BIOS chip looks for an active partition and loads the operating system.

  • The most common type of floppy diskette used today in personal computers is the 3.5-inch 1.44 MB. However newer technologies that facilitate higher capacity drives are emerging everyday. A simple way to determine approximate capacity is to multiply the number of tracks by the number of sectors per track. 80 tracks times 18 sectors would yield about 1.44 MB. A low density, 3.5-inch drive that has 80 tracks and only 9 sectors per track would yield about 720 KB.

  • The BIOS contains the POST program. POST needs RAM to work, so one of the first things POST will check is the lower contiguous portion of RAM.

  • Math functions, sometimes referred to as floating point functions, are built into the CPU. CPUs have had math capabilities built into the chip since the advent of the Intel 486 chip. Prior to the 486, a separate math co-processor chip handled the math functions of the PC.

  • When replacing one chip with an identical chip the most important thing to remember is the orientation of the chip as it applies to the socket. Most CPUs have a notched corner that must be aligned with a corresponding notch in the socket.

  • Most PC modems, whether internal or external, are usually serial devices. External modems can be attached to any serial port, however you must configure your software for that port through COM1 or COM2, for example. Serial ports are often referred to as RS 232 ports.

  • The length of a SCSI cable is critical for proper operation. A SCSI cable should not exceed 3 meters or approximately 20 feet. As you approach the length limit, errors will increase.

  • The floppy cable will determine whether a drive will be identified as the 'A' drive or 'B' drive. The drive connected to the end of the cable with the twist will usually be the 'A' drive. The drive connected to the middle connector will be the 'B' drive.

  • Computer manufacturers spend large amounts of time and money engineering case design to create optimal airflow. If empty slots are not covered, the airflow may change enough to cause heat related problems.

  • The standard Hayes compatible code to dial is ATDxxxxxxx. A 'T' is sometimes added to signify tone dial.

  • The CPU on the newer style system boards will usually be mounted into a ZIF (zero insertion force required) socket. This type of socket makes removal and replacement of chips much easier than the older soldered types of mounting.

  • Computer manufacturers spend large amounts of time and money engineering case design to create optimal airflow. If empty slots are not covered, the airflow may change enough to cause heat related problems.

  • You should always check your local laws concerning disposal of batteries or toxic cleaning supplies. Generally, just throwing batteries away could lead to environmental hazards.

  • Universal Serial Bus (USB) is a new connection interface for all types of peripheral devices. USB replaces all the different kinds of serial and parallel connectors with one standard plug and port combination. Another nice feature of USB is "hot swapping" which allows you to attach a device and have the PC detect it, without restarting your machine.

  • The typical DIMM configuration is 168 pins. SIMM memory is configured with 30 and 72 pins.

  • The most common type of computer network cable used today is twisted pair (category 5) cable. This four pair wire uses an RJ45 connector. The RJ45 is a somewhat larger version of the RJ11 telephone connector, except the RJ11 only uses two pair of wires.

  • The ansi.sys device driver expands the ability of a system to respond to advanced video command sets. The ansi.sys driver must be loaded in the config.sys file.

  • Virtual memory allows for the creation of a file on the hard disk that will simulate actual system RAM. This is used by applications when they require more memory than is physically installed in the machine.

  • Internal DOS commands are those commands that are built into the command.com program. Examples of these commands are DIR, COPY, CD, CLS. As the name implies, these commands are available as soon as the command.com program is loaded. External DOS commands are those that must be physically present on the hard disk. The DOS format and Fdisk programs are both examples of external DOS programs.

  • Prior to Windows, the most common application installation program was install.exe. Windows 3.x and Windows 95 both use setup.exe as the default installation program file.

  • From a DOS command prompt you can press the F3 function key to recall the last command typed. Later versions of DOS expanded this functionality with the DOSKEY program. DOSKEY is a TSR program that allows you to scroll through previous commands by using the up and down arrows.

  • The CMOS (Complementary Metal Oxide Semiconductor) holds system information, such as time, date, installed memory and the type of drives installed in the machine.

  • The Pentium® Pro processor is the first Intel processor to combine Level 2 (L2) cache in the same package as the CPU. The Pentium Pro processor is a dual-chip configuration that houses the Pentium Pro CPU on one side of the dual-cavity package and the L2 cache memory on the other.

  • If you don't know the answer to a question, be up front about it. Tell the customer that you don't know but you will find out and get back to them.

  • When a part is late, even if it is not your fault, let the customer know. Apologize for the delay and let them know you are looking for another source for the part.

  • It's important to be polite, but remember that the most important issue is to make sure the customer is satisfied. Let the customer try out the system to be sure the problem is fixed.

  • Especially when fixing computers, there are times when schedules just don't work out. Troubleshooting is nowhere close to an exact science. The customer may not know this or care. There is a problem and the customer wants it fixed. The only thing you can do is be honest about the situation. Explain that a job is taking longer than planned, apologize for not being there on schedule, and give an approximate time when you can make it. If the new time doesn't work, offer to reschedule.

  • Users learn from their errors, especially if they can fix the problem themselves, with your coaching. Speak slowly when giving instructions and anticipate the user's technical level when explaining the repair procedure. You may have to break down the information into less technical terms so the user can fully understand the process.

  • Computers must agree on a common language before they can communicate. In networking terms, this is called a protocol. Examples of protocols include TCP/IP, NetBeui, and IPX.

  • Bandwidth is the size or width of the transmission channel. It is determined by subtracting the lowest from the highest frequency.

  • If a network card is not configured properly, it will prohibit network access. It will not crash the system or cause any damage. You can still power up the PC, but you will not be able to access the network.

  • PCI network interface card IRQs are configured with the operating system, CMOS and BIOS.

  • Before installing a NIC (Network Interface Card), it's important to read the configuration text files. They may give you important instructions regarding the jumper settings for the NIC. The EPROM chip can be configured after the NIC is installed.

  • There are three types of PCMCIA card slots. Type III is for removable hard disks. It is the thickest slot in the portable system.

  • To better manage your memory you should: Use a memory manager to free additional memory for DOS applications by loading system drivers into upper memory above 640K; Remove unnecessary drivers by editing your config.sys and autoexec.bat files; Create a batch file that switches you between separate system configurations - one for the office and one for the road.


    WINDOWS 95

  • Technically, the Registry is one database that contains all the settings for your computer. This database is divided into two separate files for ease of administration. The files are user.dat and system.dat. and are typically located in the Windows folder.

  • The Windows 95 Explorer program is what File Manager was to Windows 3.x. The Windows 95 Explorer lets you view and search the file system for folders, subdirectories and files. If a folder contains other subdirectories and files, it is denoted by a plus sign enclosed in a small box to the left of the folder.

  • Windows 95 will create backup copies of these two files every time the computer is rebooted. The user.dat file is copied to a file called user.da0 and the system.dat file is copied to the system.da0 file.

  • The Start Button is a new feature to Windows 95. It allows you easy access to some of the more commonly used functions of the software, including searching the system for files and folders. By clicking the Start Button and choosing ‘Find,' then ‘Files or Folders,’ you can then enter a specific file name or search for all files having a common extension by using the * wild card switch.

  • The right-click function in Windows 95 allows you to modify an object’s properties. In the case of a folder you can set attributes like Read-only or Hidden and also enable sharing of a folder.

  • Windows 95 ships with two very useful disk-related tools: Defrag and Scandisk. The Defrag utility, as the name implies, will organize and optimize a badly fragmented hard disk. The Scandisk program will search the hard disk for errors and attempt to repair and flag them.

  • Windows 95 will run the Scandisk tool automatically as required if, for example, Windows was shut down improperly. However, you can start Scandisk or Defrag from the Desktop by clicking Start and choosing Programs, Accessories, and System Tools.

  • The Windows 95 installation program creates two text files during installation that can be very useful in troubleshooting any problems that occur during the setup phase. These files are detlog.txt and setuplog.txt.

  • The setuplog.txt file contains information about what happened during the setup phase. The detlog.txt file contains information about hardware components and their settings.

  • The Windows 95 installation files found on the installation CD are compressed. During installation they are decompressed to the target drive location. The installation files on the CD have a .cab extension. They are referred to as cabinet files.

  • In Windows 95 you can right-click the printer icon and from the pull down menu, choose ‘Set as Default.’ This default printer will then be used by all your Windows-based applications. You can also Pause and Purge print jobs from this same pull down menu.

  • When you install Windows 95 from a Windows 3.x machine, the Upgrade version of Windows 95 will search your hard disk for a current version of Windows. If it cannot find it on the disk, Windows 95 will ask you to insert a Windows 3.x Installation disk.

  • Windows 95 requires that all older 16-bit programs share the same memory space to ensure backward compatibility with Windows 3.x. Because of this sharing, it is possible that one program can step on (overwrite) the memory area of another. This will usually generate a general protection fault error code.

  • The System Monitor utility is a Windows 95 tool for tracking memory and other resources for possible problems. System Monitor gives you the ability to track a variety of options depending on the components installed in your machine.

  • You can track system resource usage by selecting the Resource Meter utility from the System Tools group. The Resource Meter dialog box will display usage for the following three categories: System resource, User resources and the GDI (graphics related) resources.

  • Unlike previous versions of DOS, Windows 95 supports long file names, up to 255 characters including spaces. These restrictions apply to both files and folders. The following characters are considered illegal and cannot be used:
    / \ * ? " : < > | .

  • Windows 95 file and folder names are case preservative, but not case sensitive. An example might be if you named a file Resume.doc. The capital "R" would be preserved, but could be referenced as resume.doc.

  • The GDI (Graphical Device Interface) provides Windows 32 bit programs with an interface and services to interact with graphical devices, like the CRT and printers.

  • Windows 95 has configured several shortcut keys that can be pressed during the boot process to aid in troubleshooting. The following is a list of these special function keys:
    F8 Startup menu
    F4 Previous version of MS-DOS
    F5 Safe mode
    Ctrl+F5 Safe mode without compression
    Shift+F5 Safe mode command prompt only
    Shift+F8 Step by Step confirm
    F6 Safe mode….with network support loaded


  • The proper time to press a function key is after your machine has finished running POST. This is usually when the Starting Windows 95 message appears on the screen.

  • There are many types of viruses that will attach to and corrupt the MBR (master boot record) which may cause Windows to fail during the boot process. If this should happen, you can usually boot to a ‘clean’ floppy and run the Fdisk /MBR command which will restore the master boot record and eliminate the virus.

  • When you first install Windows 95 it gives you the option to create an Emergency Repair Disk. This is basically a bootable floppy disk that contains Windows 95 Startup files. The Emergency Repair Disk can be used as an aid in troubleshooting situations. If the disk was not created during the initial installation, you can create it by opening Control Panel, then double-click Add/Remove Programs, click the Startup Disk Tab and click Create.

  • When a Windows 95 machine is booted in the Safe mode, it will load just the minimal set of drivers needed to function. This is very akin to the ‘good old days’ when a DOS machine was booted with a clean floppy (loading no config.sys or autoexec.bat). In the case of the above example, the mouse, keyboard and standard VGA driver are the minimum requirements to perform a successful boot.

  • In order for a Plug and Play system to function, the BIOS, Operating System, and hardware must all be capable of working together. That is why it is very important to ensure that your hardware is Plug and Play compliant.

  • With Plug and Play enabled Windows 95 can automatically detect and configure hardware installed in the machine. It is most important to note that PNP will only be successful if the hardware and associated drivers are PNP compliant.

  • Windows 95 is neither a 16-bit nor a 32-bit operating system, but rather a hybrid mixture of 16-bit and 32-bit components. However, having stated this, if one is pressed to choose between 16 and 32-bit for the sake of argument, 32-bit would be the most correct answer. But the most correct answer for this question would be a mixture of 16 and 32-bit.

  • Technically, the Registry is a database that contains the configuration information. The Registry is divided into two separate files, the user.dat and the system.dat. Both the user.dat and the system.dat files are hidden, read-only files located in the Windows directory.

  • Windows 95 will backup the two Registry files user.dat and system.dat to user.da0 and system.da0 located in the Windows directory. Both the .dat files and the backup files (.da0) are hidden read-only files.

  • When a new application is added in Windows 95 it usually will be installed to a new directory created by the application. It is very important to remember that if you must remove an application, do not simply delete the folder. The preferred method is as follows: Open the Control Panel, choose Add/Remove Programs, select the program and Remove. This procedure will ensure that the operating system will search for and remove all references to the program. If you delete just the folder that contains the application, there still could be hooks and links in other locations.

  • Windows 95 has the capability of using long file names, up to 255 characters including embedded spaces. However, not all programs can handle or understand long file names and DOS is one of these. To accommodate the programs that only accept 8.3 characters, Windows will display only the first six characters, dropping any spaces, then will add a tilde (~) followed by a sequence number.

  • Windows 95 includes a Backup utility that lets you backup important files from your hard disk to floppy diskettes or tape. The Backup utility is located in the System Tools folder.

  • Windows 95 uses TAPI (Telephony Application Programming Interface) as an interface to devices that need telephony access. This standard interface makes it easy for third party developers to create programs that are modem ready. You can view the TAPI settings by clicking on the Dial Properties button for your modem in Control Panel.

  • Prior to Windows, the most common application installation program was install.exe. Windows 3.x and Windows 95 both use setup.exe as the default installation program file.

  • The Windows 95 operating system still supports .INI files for backward compatibility. Most of the information stored in the Windows 3.x .INI files is imported into the Registry during a 95 upgrade. However, some of these configurations were left in the System.ini, Winfile.ini and the Win.ini to facilitate the compatibility issues.
    The Win.ini files contain the RUN= line that will automatically run a program when Windows is started. The syntax to automatically start the calculator program would be RUN=C:\windows\calc.exe.

  • Explorer is the Windows 95 equivalent to File Manager in Windows 3.x. Both Explorer and File Manager allow you to view, copy and create files, folders and directories. To view hidden files from within Explorer, you would choose View from the pull down menu then Options and select Show All Files box.

  • One of the many new features in Windows 95 is the addition of the Start button. The Start button located in the lower left-hand portion of the screen facilitates finding and starting programs.

  • If Windows reports a display adapter message, the first place to check would be display Video Properties. This can be accomplished by right-clicking the Desktop or through the Control Panel.

  • For various diagnostic purposes, Windows 95 will allow you to start Windows without launching any programs in your Startup group by holding down the left Shift key while booting Windows.

  • The official DOS requirement for installing Windows 95 is DOS 3.2 or later. However, the preferred option would be DOS 6.2x to ensure compatibility and to facilitate dual- booting function.

  • The Advanced Graphic settings in System Properties tell Windows how to interact with your graphics hardware. This area can be very useful when troubleshooting display-related problems.

  • Windows 95 installation requirements include DOS 3.2 or higher, a hard disk with a FAT partition, and a minimum of 50-55 MB of free space.

  • In order for any two computers to communicate with each other, they must be speaking the same language or protocol. In Windows 95 you can configure the protocol that your machine will use. Windows 95 supports three major protocols: TCPIP, IPX/SPX and NetBEUI. Support for other protocols is also available. An example is NETBIOS.


    INTERNET

  • The location of your ISP service is called its POP, (point of presence). Many of the large providers have locations throughout the country. When choosing an ISP, it's very important to select a provider that has a local phone number.

  • For your company's protection, a Firewall protects their local networks and computers from connections by deceitful sources. A firewall is basically a computer that is attached to both the Internet and a local network. It blocks the connections by filtering Internet addresses or protocols.

  • The World Wide Web is one of the many services of the Internet.

  • LAN stands for Local Area Network and WAN stands for Wide Area Network.

  • PPP stands for point to point protocol. SLIP stands for serial line Internet protocol.

  • The most widely used connection type is PPP. PPP lets your personal computer connect directly to the Internet over serial lines, such as telephone wire.

  • The World Wide Web (WWW), is a way to organize various pieces of information in the form of hypertext documents. The hypertext document is made up of text or pictures that are linked to other documents. Users can then click on a piece of text that will move them to a different location, perhaps just another place within the document or to a different document located on another computer.




    IRQ/IO addresses/DMA channels

        Know your IRQs. There will be 5 to 10 questions dealing with IRQs and IRQ conflicts.

              There are 16 IRQs: 0 through 15. there is no such thing as IRQ 16 and higher. IRQ is a signal that a device sends to CPU to request it's attention.

    IRQ # Device
    0 System timer
    1 Keyboard
    2 Cascade to IRQ9. Can't be used.
    3 Com ports 2 and 4
    4 Com ports 1 and 3
    5 Usually available. Sometimes LPT2. Most often used for sound cards.
    6 Floppy drive
    7 LPT1
    8 Real time clock
    9 Video display adapter
    10 Available
    11 Available. SCSI adapter will usually use this IRQ.
    12 Available or PS2 mouse
    13 Math coprocessor.
    14 Primary IDE controller
    15 Secondary IDE controller. If there is no secondary IDE controller on the board, or secondary IDE controller is disabled in CMOS, IRQ 15 is available

    Memorize your DMA channels. DMA stands for direct memory access and allows a device to access the RAM directly, bypassing the CPU. Only one DMA channel can be assigned to one device. Most systems today have 2 DMA controllers and 8 DMA channels 0 through 7. There is no DMA 8

    DMA Device
    0 Available
    1 Available
    2 Floppy drive
    3 Available
    4 2nd DMA controller
    5 Available
    6 Available
    7 Available

    You need to remember the base memory addresses for communication ports.

    Port Base address
    COM1 h3F8
    COM2 h2F8
    COM3 h3E8
    COM4 h2E8
    LPT1 h378
    LPT2 h278

    CPU TYPES

    Memorize the types of CPUs. The exam does not go into details of what year certain CPU first came out, but you need to know what CPU introduced the real mode and what CPU has the coprocessor disabled.

    CPU Comment Model year External clock

    in MHz

    		 Internal clock

    in MHz

    		 Can access memory up to Internal cache Built in co-

    processor

    (FPU)

    		 Internal bus External bus
    8086 First CPU 1978 5 5 1 Mb no no 16 bit 16 bit
    8088 Used in the first IBM PC/XT computer. 29000 transistors. 1979 8 8 1 Mb no no 16 bit 8 bit
    80286 Introduced the idea of protected mode. 134000 transistors. 1982 8,10,or 12 8,10,or 12 16 Mb no no 16 bit 16 bit
    80386DX Can switch between real and protected mode. First true 32 bit CPU. 275000 transistors. 1985 16,20,25,33 16,20,25,33 4 Gb no no 32 bit 32 bit
    80386SX Cheaper version of 386 known as derivative chip 1988 same as 80386DX same as 80386DX 16 Mb no no 32 bit 16 bit
    80486DX Introduced internal L1 cache. About twice as fast as 386. 1.2 Million transistors 1989 25,33,50 25,33,50 4 Gb 8 K Yes 32 bit 32 bit
    80486SX Same as 486 but with disabled co-processor 1991 same as 486DX same as 486DX same as 486DX same as 486DX NO same as

    486DX

    		 same as 486DX
    80486DX2 Can execute instruction in one cycle rather than 2 cycles in DX 1992 25, 33 50, 66 4 Gb 8 K Yes 32 bit 32 bit
    80486DX4 Runs at 3 times the speed of motherboard 1994 25, 33 75, 100 4 Gb 8 K Yes 32 bit 32 bit
    Pentium 64 bit data bus. Can execute 2 instructions at the same time by using superscaler technology. 2 internal 8K cache chips.Cache controller built on board. 3.1 million transistors 1993 60 or 66 60, 66, 90, 100, 133, 150, 166, 200 4 Gb 16 K yes 64 bit 32 bit
    Pentium MMX 57 additional instructions to better handle video and graphics. Improves performance in multimedia applications 50 - 100 %. To utilize MMX technology programs must be written to use MMX instructions. 1996 same as Pentium same as Pentium same as Pentium same as Pentium same as Pentium same as Pentium same as Pentium
    Pentium PRO Speculative execution, Dataflow analysis. 5.5 million transistors. 1996 66 180, 200       64 bit 32 bit
    Pentium II Uses proprietary socket design - 242 SEC slot(Single Edge Connector) L2 cache built in the cartridge. 7.5 million transistors. 1997 66, 100 233, 266, 300, 333, 350, 366, 400, 450 4 Gb 16 K Yes 64 bit 64 bit
    Pentium III Not covered on the exam 1999 100 500, 550          

    MOTHERBOARDS/ BUS TYPES/ MEMORY

    There are 2 basic types of motherboards: XT - extended technologies and AT - advance technology. ATX and baby AT arre modifications of an AT format. All Pentium II motherboards are ATX format. A characteristic of an ATX format is that the computer can be shut down by software. Modern motherboards have 2 - 3 ISA, 3 - 4 PCI and 1 AGP expansion slots. Some motherboards have built in sound card, some have built in SCSI card. Motherboard configuration is stored in BIOS.

    Expansion cards/external bus types

    Bus type Data bus  width Speed Comments .
    8 bit card 8 bit 8 MHz on of the first expansion cards. Not used in modern computers .
    ISA 16 bit 8 MHz Still in use today. Configuration is done by setting jumpers .
    EISA 32 bit 8 MHz EISA bus slots are backward compatible with ISA cards. EISA cards can be configured by software or by jumpers. .
    VESA or VL-bus 32 bit Speed of Processor Backward compatible with ISA cards. Configuration is done by setting jumpers. Most often used for video cards. .
    PCI 64 bit and 32 bit Speed of  Processor Plug and Play cards. .
    AGP 32 bit Speed of processor Used in video cards. .
    MCA 16 bit and 32 bit 10 MHz Configured by software. Proprietary IBM design. Not used in modern computers. .
    PCMCI (PC card) 16 bit 33 MHz Used in laptop computers. Some are plug and play, some software configured. There are 3 types of PC cards Type 1:  3.3 mm thick. Used for memory upgrade cards. .
    Type 2: 5 mm thick. Modem and network cards. Some are combination Modem/NIC cards.
    Type 3: 10.5 mm thick. Used in PC card hard drives.

    Hard drives.

    Low level formatting is done at the factory. It organizes the hard drive into tracks and sectors. It's possible to do a low level format on the drive but not recommended. To prepare the hard drive for installation of the operating system, you must first create a partition and set it as an active partition. Boot up with a DOS boot disk and use FDISK command to create partitions. Hard drive can have 3 primary and 1 extended partition. Extended partition can be deviled into up to 23 logical partitions.

    Typical IDE drive supports up to 528 Mb of storage. EIDE drive supports 2gb and larger partitions. A modern motherboard has 2 HDD controllers, each supports 2 devices. When installing a second hard drive, set the jumper on it as a slave drive and the jumper on the first drive as a master drive. To improve performance, choose the faster drive to be a master drive. If you only have 2 IDE devices like hard drive and CD ROM, you can disable a secondary controller in BIOS to free up an IRQ and to speed up the boot process.

    If you need to have more then 4 devices, you must use SCSI devices with a SCSI card. SCSI cards can be SCSI 1, SCSI 2, and SCSI 3 (ultra SCSI). SCSI 1 supports up to 8 devises including the SCSI card. The devices in a SCSI chain must have unique SCSI IDs. SCSI card typically have ID7. SCSI 2 is a more popular adapter and supports up to 16 devices, also has higher transfer speed. Modern SCSI cards a combination SCSI2/SCSI3 cards. Internal SCSI cable is a 50 pin ribbon cable (not compatible with SCSI 3 devices). External SCSI cable is a shielded cable with Centronics-50 or female DB-25 connector. If the question on the exam does not mention what category  a SCSI adapter is, assume they are talking about category 1 ( 8 devices ). The SCSI chain must have terminators at both ends. Terminators are resistors. SCSI card usually has a built in terminator.

    SCSI hard drives are more expensive than EIDE hard drives but offer higher access speed.

    Memory.

    The first 1024Kb of ram represents DOS memory model. Memory above the first 1024K is called Extended memory. The first 64K of extended memory is called high memory.

    Upper memory (reserved memory) 960KB - 1024KB Motherboard bios  
    768KB - 960KB Bios and Ram buffers First 64KB of this memory can be used for page frames when Expanded memory driver is loaded.
    640KB - 768KB Video ram  
    Conventional memory 0 - 640KB Conventional memory Used to load DOS(in first 64KB), run programs, load drivers, TSRs

    Types of memory.

    SRAM Static random access memory Older type of ram. Uses transistors to store information
    DRAM Dynamic random access memory Uses capacitors to store memory.
    ROM Read only memory Data in ROM can not be erased or changed
    PROM Programmable ROM After the data is programmed into ROM, it can't be erased or changed
    EPROM Erasable PROM Data can be erased by shining special ultraviolet light through a small window on the chip. The chip can then be reprogrammed.
    EEPROM Electronically erasable PROM Data can be erased by sending a special electric charge. Chip can then be reprogrammed. Modern computers use EEPROM to store BIOS.
    VRAM video ram Special type of ram used on video cards.
    Cache memory memory used to cache CPU instructions L1 cache located on CPU. L2 cache is external cache, located on motherboard.

      PRINTERS

      2-4 questions on the exam will be about laser printers. Those are easy if you remember how laser printers work. 2-4 questions will be about other type of printers like bubble jet, ink jet and dot matrix.

    Laser printers

      Process Description
    1 Cleaning EP drum is cleaned with a rubber blade before it can take on a new image
    2 Conditioning The EP drum is given a negative charge of approximately -600 Volts by the primary corona wire
    2 Writing A laser beam is used to write to the EP drum, causing the dots on the drum to loose some of the negative charge and become relatively positively charged.
    3 Developing A toner is transferred from the toner cylinder to the EP drum by attracting to the area of the drum that has relative positive charge.
    4 Transferring The transfer corona wire charges the paper with a high positive charge. The EP drum turns as the paper passes under It, pulling the toner into the paper. A static charge eliminator prevents the paper from wrapping around the drum.
    5 Fusing The paper passes between the heated fuser   roller and the rubber roller, the toner is melted and pressed into the paper. The heated roller reaches the temperature of about 180 degrees Celsius. The temperature sensor on the fuser roller will shut down the printer if the temperature gets dangerously high. Finally the excess toner is scrubbed of the paper by the cleaning pad
    6 End of cycle The paper with the final image is rolled out of printer. The eraser lamp is turned on near the surface of the EP drum, causing the drum to loose it's charge.
    The toner is a combination of plastic, metal and organic compounds. In most laser printers the toner and EP drum are contained in one "toner cartridge". Do not recycle the toner cartridge, it needs to be replaced.
    A paper jam can occur when the wrong type of paper is used. It can cause more than one page to enter the registration rollers. A jam cam also be caused by the bad separator pad.

    Other printer types

    Type Process Comment
    Daisy-wheel printer. A computer version of an electronic type writer. One of the first types of printers developed. Not used any more
    Dot matrix (impact printer) Combination of pins on the printhead hit the ribbon, causing it to leave the marks on the paper. Useful when you need to print carbon copies like receipts or shipping invoices. Typical printhead has 9, 18, or 24 pins. Printhead becomes very hot. Don't touch it. Never lubricate a printhead. If the ribbon is too tight, the image can become smudged. Broken pins on the printhead will cause incomplete characters.
    Ink Jet Ink is pumped from the reservoir through a nozzle by a special pump. Ink jet printers were messy and were replaced with bubble jet printers.
    Bubble Jet Ink cartridge contains ink, printhead and   special piezoelectric crystal. When signal is send to the crystal, it expands, forcing the ink out. Do not refill bubble jet printer cartridges. They need to be replaced.

     Cables

    Cable type Connectors Maximum length
    Modem cable RS - 232 DB-9F, DB-25M 25 feet
    Modem cable RS - 232 DB-25F, DB-25M 25 feet
    Printer cable DB-25M, Centronics 36 10 feet
    External SCSI cable Centronics 50M, Centronics 50M 10 feet
    VGA cable DB-15M, DB-15M 3 feet

     Display adapters/Monitors

    Adapter type Resolution Colors
    XGA (extended graphics array) 600X800 65,536
    1024X768 256
    SVGA (super VGA) 640X480 65,536
    600X800 256
    1024X768 16
    CGA (color graphics adapter) 320X200 4
    640X200 2
    EGA (enhanced graphics adapter) 640X350 16
    VGA (video graphics adapter) 640X480 16
    320X200 256

    Modems

    Modems use asynchronous  transmission. Digital modems use synchronous transmission. Digital modems are used to connect to ISDN lines.

    Modem commands Command function
    ATA Answer
    ATD Dial
    ATH Hang up
    ATZ Reset

    Basic network terminology

    LAN Local area network. Typical network inside an office or inside a building
    MAN Metropolitan area network. A network that connects several LANs in a city.
    WAN Wide area network. A network that spans over long distance. Internet is an example of WAN.
    TOPOLOGY A way to lay out a network.
       

    Preventive maintenance/Safety/Troubleshooting  

    Electrostatic discharge (ESD) can damage the component at as little as 80 volts. CMOS chips are most susceptible to ESD. Static electricity builds up more in cold and dry places. Use humidifiers to keep room humidity at 50% to prevent static build up.

    When working on computers, use special ESD wrist strap. Do not use a piece of wire to ground yourself. An ESD wrist strap has built-in resistor to prevent electric shock. Use specially designed grounded ESD mats. Do not wear synthetic clothing. Place all electronic components into antistatic bags. Antistatic bags can be reused. Keep your workplace clean.

    When repairing a monitor, do not wear an ESD wrist strap. The capacitor inside the monitor can retain high voltage charge.

    To put out an electrical fire use type C extinguisher or multipurpose ABC type extinguisher.

    Do not disassemble power supplies. They need to be replaced.

    To clean a keyboard soak it in a distilled demineralized water as soon as possible after the spill.

    Clean the inside of the PC with compressed Air. Compressed Air do not create ESD.

    Multimeters can be used to test a fuse. A good fuse will show resistance of 0 ohms. A bad fuse will show infinity ohms. When testing an unknown source of electricity, set the multimeter to the maximum voltage settings to avoid damaging the multimeter.

    If a light an a floppy drive stays on, reverse the floppy cable to solve the problem.

    For more information visit CompTIA.

    To register for the exam call 1-800-77-MICRO or go to www.2test.com

    Reggies A+ site. Practice tests, A+ forum, Links   http://ios.hypermart.net/Aplus/




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