Input, Process, Output
Supplemental Lecture Notes
Typical System
Computer case
Monitor
Printer
Speakers
Modem
Keyboard
Mouse
Computer ComponentsPower supplyHard driveExpansion cardExpansion slotSystem boardCD-ROM or DVD-ROMFloppy diskDrive bayCentral Processing Unit (CPU)Random access memory (RAM)
Power Plays
The capacity of a power supply is measured in watts
Computer uses 250; light bulb uses 60
Can useSurge protector
UPS
Ports
Ports are connectors at the back of a computer system that you use to plug in an external device. This allow instructions and data to flow between the computer and the device
Any Port in a Storm
Parallel port – 25 holes; female connector; LPT1; printer or storage devicesMonitor portKeyboard portSerial port – 9 or 25 pins; male connector; COM1; mouse or modemGame portNetwork portUSB port
127 devicesPrinter, modem, joy stick
Growing
An expansion card is a circuit board that lets you add new features to a computer
Video
Modem
Sound
Network Interface
Upgrades
Upgrading refers to replacing an old or obsolete component with a newer component to improve the efficiency of the computer
Upgrading also can include adding a new component like a tape drive or DVD to increase the capabilities of a computer
Increasing the amount of memory in a computer is one of the most effective upgrades you can perform
Input and Output
Chapter 2
Mouse Actions
Click – selects
Right click – displays commands
Double click – opens
Drop and Drag – moves items on screen
Mice
TypesConventionalWheel mouseWireless mouseProgrammable mouse – e.g. three buttonsOptical sensor mouse
Other devicesTouchpadTrackballPointing stick
KeyboardsThere are 101 keys on a keyboard to help you input informationFunction keys let you perform specific taskCan use CNTL-x shortcuts to execute commands
CNTL-C – copyCNTL-X – cutCNTL-V – paste
Windows key will quickly display the start menu
Printers
Speed of a printer is measured in pages per minute (PPM). A higher speed represents faster output
Resolution determines the quality of imagesA higher resolution results in sharper images
Printer resolution is measured in dots per inch (dpi)600 dpi is acceptable; 1200 is better for images
Resolution expressed with two numbers represents dots per inch across and down
Types of PrintersInk-jet: has a print head that sprays ink through tiny nozzles onto a page
2 to 10 pages (ppm)360 to 2400 dots per inchColor printers spray cyan, magenta, yellow and black to create different colors
Laser-printerWorks like a photo copierSpeed of 4 to 16 pagesHave a CPU600 to 2400Memory – 2mb to 8 Mb
Other Types
Dot matrixPrint head contains small blunt pins that strike an inked ribbon
Useful for multi-part forms
LED printerSimilar to lasers but cheaper
Color photo printerMultifunction Printer
Print Buffer and Spoolers
Printer buffer: section of memory printer stores information waiting to print
Printer spooler: program on your computer that stores information waiting to print
Stores more information than the buffer
One spooler for each connected printer
Monitors
Video cards translate instructions from the computer into a form Most computes the monitor can understand
require at least 2 mb of video card memory
Accelerated Graphics Port (AGP) – uses AGP bus to communicate directly with main memory
3D Graphics Accelerator has chip called a GPU optimized for 3-D graphics
Monitor Metrics
The smaller the dot pitch, the crisper the image
0.28mm is acceptable
Refresh rate is measured in hertz (Hz)Times per second computer redraws the image
72 Hz or more is acceptable
Resolution
Amount of information a monitor can displayMeasured by the number of horizontal and vertical pixels
Monitors switch settings based on the resolution and refresh rate of video card
Video card determines number of colors a monitor can display
256 suitable for most home use
24-bit displays more colors than eye can distinguish
CommunicationsModems let a computer exchange information through telephone linesSpeed of a modem determines how fast it sends and receives messages
56,000 bps (56 Kbps)V.90 standard: receive 56K and send 33.6K
Speed at which information flows depend on the quality of the phone line
A modem needs a communications package to manage the transmission of informationData compression – squeezes together data
High-speed ConnectionsISDN – Integrated Services Digital Network
Digital phone line
56 Kbps to 128 Kbps
Cable ModemSame cable as TV
4000 Kbps
DSL – Digital subscriber lineHigh speed digital phone line
1000 – 6000 Kbps
Satellite
Sound Cards
Sampling Rate: at least 44.1 KHz
Full-duplexTalk and listen at same time
Musical Instrument Digital Interface (MIDI) support
Wavetable synthesisActual recordings
FM synthesisImitated sounds
TV Tuner Cards
Require a video card to operate
ScannersA scanner is a device that reads images and text into a computer
Most scanners come with Optical Character Recognition (OCR) software. This software places scanned text into a document that can be edited in a word processorColor dept is measured in bits and indicates the number of colors a scanner can detect
36 bit color depth is acceptable
Resolution
Resolution determines the amount of detail a scanner can detect
Ranges from 600 dpi to 2400 dpi
You usually don’t need to scan at a higher resolution than a printer can produce or a monitor can display
– Most monitors are 73 dpi
– Printers vary
Cameras
Resolution is measured in megapixels1000 x 1000 pixels1, 2 and 3 megapixel cameras are available
Digital video cameras use a Charged Coupling Device (CCD) to capture video
Quality depend on amount of detail a CCD can detectMost CCD’s have resolution between 250,000 and 700,000 pixels
Web cameras – resolution and speed determine quality of image
Common transfer rates15 frames per second at 640 x 480 pixels30 frames per second at 352 x 288 (clearer but smaller)
MP3
Sound format used to CD-quality music over the Internet
Compresses sound
Commonly 64 bit memory
USB and Firewire
High-speed ports that allow information to quickly transfer between a computer and an external device
USBSupports up to 127 device
– USB 1.0: 12 megabits per second
– USB 2.0: 480 Mbps
FIREWIRE63 devices at 400 Mbps
Can purchase Firewire expansion card
Processing
Chapter 3
CPU (Central Processing Unit)Processes instructions, performs calculations, and manages the flow of information Performance:
CPU speed is a major factor in determining how fast a computer operates (faster the speed, faster computer operates)
Measured in megahertz (MHz) A clock cycle relates to the clock that controls the timing in the microprocessor. For example, a 900MHz (megahertz) clocked microprocessor generates 900 million clock cycles per second.
Each generation of CPU is more powerful than the one before. It's clock cycles are faster at a given speed
Processing
The Central Processing Unit (CPU) is the main chip in a computer
Processes instructions
Performs calculations
Manages the flow of information
Types of CPUsIntel Pentium Processor
Speeds of 450 MHz to 1.13 GHz
Intel CeleronNeeds of home machines (500-700MHz)
AMD Athlon ProcessorBusiness and home use
AMD Duron ProcessorHome use
VIA Cyrix ProcessorInexpensive CPU
ProcessingRandom Access Memory – Temporarily stores data inside a computer
Constantly overwrittenMeasured in megabytes (MB)
64 minimum these days100 MHz (millions of cycles per second)
Dynamic RAM is type of memory chip that makes up memory in many computer systems. Access speed measured in megabits
Most system boards can support access speed of Single Inline Memory Module (SIMM) – 9 memory chipsDual Inline Module (DIMM) – 18 memory chips
If you have limited memory or you have many programs open, your computer may need to use part of the hard drive to simulate more memory
Using Memory Cache
1. Look through documents on your desk (internal cache)
2. Look through documents in your desk drawer (external cache)
3. Looking through documents in your filing cabinet (RAM)
Using Memory Cache
1. Look through documents on your desk (internal cache)
2. Look through documents in your desk drawer (external cache)
3. Looking through documents in your filing cabinet (RAM)
Math CoprocessorsA special processing unit that assists the CPU in performing certain operations.
A math coprocessor is a chip or part of a chip that specializes in doing math. Hardware that attaches to the motherboard or is part of the CPU.
Extends the capabilities of a CPU in a transparent manner. Performs mathematical computations, particularly floating-point operations. Besides being able to add, subtract, multiply and divide floating-point numbers, they can also operate on them to perform comparisons, square roots, logarithms, sine, cosine, tangent, absolute value, and remainders
Also called numeric coprocessors or floating point units (FPU).