A+ exam notes
- The four basic components of any computer are input, output, storage and processing
- ASCII = American Symbolic Code for Information Interchange. 128 char. Extended 255 char.
- Six fundamental microcomputer components: processor, bus, memeory, disk, video, input/output
- Old school bus types ISA,EISA,VESA, MCA
- Another name for a system board is the planar board
- The nucleus of the PC is the CPU
- A measurement of speed is MegaHertz
- Clock speeds are measured in megahertz
- The larger the cache, the faster the processor
- the 80286 is equated with the AT and ISA busses
- The MCA bus was predominatly used by IBM
- EISA took the most popular features from other busses and expanded on them.
- the VESA bus is also klnown as the VLbus
- PCMCIA cards were designed for notebook use
- Memory is a storage area for fast access.
- Character strings are groups of alphanumeric data
- Two factors fro evaluating surge supressors are clamping speed and clamping voltage
- RAM is volitile memory
- ROM is non volitile memory
- Line conditioners may help with unstable power sources.
- The smallest unit of storage in DOS is a cluster
- Versions of DOS prior to relase 4.0 support a maximum partition size of 32 MB
- A double sided 5 1/4" diskette can be formatted to a maximum of 360 KB
- The cabling for a floppy drive has a twist in it, on the drive end of the cable.
- Labeling connections to components is a good idea.
- To prevent ESD, use a grounding strap.
- An interrupt allows the computer to suspend what it is doing in order to do something else.
- The DMA channel for floppy controllers is 2
- RAID = Redundant Array of Inexpensive Disks
- Eash device on a PC must have a unique IRQ
- Older expansion boards may use jumpers or DIP switches that need to be set.
- A DMA channel allows a peripheral device a direct path to RAM
- The first thing a POST does is to reset the CPU and program counter to F000
- Windows near a PC location should have a curtain to reduce the heat effect of sunlight
- The first step in troubleshooting a PC is to eliminate the possibility of operator error.
- FDISK is an old school way of fromatting a drive.
- ICs installed on a circuit board can work lookse over time- this is due to thermal cycling (thermal expansion)
- Soft memory errors are caused by random events.
- A hard memeory error is caused by a fialed RAM chip.
- Voltages may range as high as 15,000 volts in a CRT monitor.
- The POST test is stored in PROM
- a keyboard failure is a 301 error code.
- To conect an ohmmeter to read the value of a circuit, make sure the gate is open.
- to connect a voltometer to read the value fo a circuit, connect it in parallel.
- On a standard wall outlet, the smaller of the two slots is considered hot
- If an outlet is wired backward, it may cause you to get a shock.
- On older disk drives, constant spinning may cause the magnetic oxide to shift outward.
- To set up an ESD workstation, place the PC on a grounded mat and connect a wrist strap.
- CMOS chips are very susceptable to ESD
- Magentic fields can cause distortion on video displays and loss of data on magnetic storage devices
- The difference between a spike and a surge- spike=very short, surge =longer
- power sag- momentary undervoltage condition
- brownout -prolonged shortage of power
- transient - overvoltage condition
- True grounding wrist straps contain a resistor- it is not just a piece of wire.
- ODI Open DataLink Interface
- VLM Virtual Loadable Module -used in oldschool novell networks
- LSL Link support Layer
- In Token Ring, stations communicate only in one direction
- Fiber Optic cable is not prone to electromagnetic interference
- A line printer absorbs the characters sent by the client, but does nothing until it gets a carriage return.
- Page printers acquire a whole page of data before actually printing.
- The conversion of characters and drawings to dot patterns is called rasterization.
- The RIP - Raster Image processor. RIPs use a RISC architecture.
- Working memory is used by the RIP to store the bit image that will be printed on the page
- The print spooler is msmory used to store jobs before printing them.
- DPI Dots Per Inch - the number of dots in one linear inch
- CPS Characters perSecond
- PPM Pages Per Minute
- Engine Speed - a maeasure of the rate that paper rolls through the imaging mechanaism of the printer
- Fonts built in the printer are called resident fonts.
- main components of a laser printer - Photosensitive Drum, Cleaning Blade, erasure lamp, primary corona, writing mechanism, toner, transfer corona, fusing roller
- Toner is moved to the print media by the transfer roller.
- Toner is transferred from the drum to the print media by a strong negative charge on the corona wire
- The conditioning wire applies a uniform negative charge to the photosensitive drum.
- The fuser assembly melts toner particles andpresses them onto the print media.
- The corona wire transfers the toner to the print media.
- The printware in a dot matrix printer is fired via an electromagnet, forcing the printwire away from a magnet in the printhead.
- the six steps of the electrophoto process (EP) - cleaning,conditioning,writing,developing,trasferring, and fusing.
- A toner cartridge contains a drum, charging roller, developing roller, and scraper blades.
- Finish refers to the smoothness of the print media.
- Basis weight - the weight in pounds of 500 sheets of 17x22.5 paper
- Paper path- the route paper takes through the printer.
- Friction Feed- Printers grab paper between rubber rollers and use the force of the friction to keep it from slipping.
- Cut Sheet feeders feed individual cut sheets through the printer. Also known as bin feed systems.
- Debouncing- cleaning up electrical signals created by the keyboard.
- LDL Locacal Digital Loopback. Tests the transmitter and reciever of a remote modem and the phone line.
- The hinge on a notebook is rated on the number of times it opens and closes.
- Plasics in notebooks are build using EMI sheidling.
