Summaries of Computing Fundamental
1A. Exploring Computers and Their Uses
1. A computer is an electronic device that converts data into information.
2. Digital computers represents data as numbers..
3. Analog computers represents data as variable points along a continuous spectrum of values.(Older computers)
4. Computers for individual users: (PC, microcomputers)
(1)Desktop computers:
i. System Unit is the main component of a desktop PC, which houses computer’s critical parts.
ii. Vertical models have become more popular.
(2)Workstations:
i. More power and features than a desktop PC.
(3)Notebook Computers: (Laptop Computer)
i. Weighting less than 8 pounds.
ii. Categorized as mobile computers.
iii. Can be plugged into docking station, which provides additional ports.
(4)Tablet PCs:
i. Notebooks that accept pen(called stylus, digital pen) inputs.
(5)Handheld PCs:
i. PDA is a popular type of handheld PC.
(6)Smart phones:
i. Cellular phones that double as miniature PCs.
5. Computers for organizations:
(1)Network Servers:
i. A powerful PC used as the central computer in an organization’s network.
(2)Mainframe Computers:
i. Used to frequently usage of data.
ii. User access mainframe computers through a device called terminal. iii. Dumb terminals served as I/O devices, and intelligent terminals can perform some
operations. Terminals usually don’t have storage.
iiii. Offers in power but lack in flexibility.(It operates specific works)
(3)Minicomputers:
i. Its capability is between mainframes and network servers, hence also called midrange computers.
(4)Supercomputers:
i. The most powerful computers, and physically the largest ones.
6. Computers in society use:
(1)Home: Communications, Schoolwork, Entertainment, Finances.
(2)Education
(3)Small business
(4)Industry: Design, Shipping, Process control.
(5)Government: Population, Taxes, Military, Police.
(6)Health Care
1B. Look Inside the Computer System
1. A complete computer consists of four parts:
(1)Hardware: Mechanical devices that make up the computer.
(2)Software: A set of instruction that makes computer perform tasks.
(3)Data: Pieces of information, which doesn’t make much sense themselves.
(4)User: Computer operator.
2. Information processing cycle:
Input→Processing→Output→Storage
3. Essential computer hardware:
(1)Processor Devices: The brain of the computer, which organizes and carries out instructions that come from the user or the software.
i. Processors usually consists special chips, called microprocessors.
ii. A microprocessor can be plugged into the motherboard, which is an example of a
circuit board.
iii. Central processing unit(CPU) refers to a computer’s processor.
(2)Memory Devices: One or more chips that store data and program instructions.
A. Random Access Memory(RAM):
i.The term “memory” is typically used to mean RAM.
ii.RAM is also called read/write memory.
iii.RAM is volatile, meaning that it loses its contents when shut off.
iiii.RAM tremendously impact on the speed and power of a computer.
iiiii.The most common measurement unit for describing memory is byte.
B .Read-Only Memory(ROM):
i.Permanently store its data.
ii.ROM is also called non-volatile memory.
iii.ROM holds instructions that the computer needs to operate, and information
about its hardware devices.
(3)Input and Output (I/O) Devices:
A. Input Devices: Accept data and instructions from the user or another computer.
Keyboard, Mouse, Trackball, Touchpad, Joystick, Scanner, Digital Camera, Microphone…
B. Output Devices: Return processed data to the user or another computer.
Monitor, Printer, Speaker, Head Phone…
C. I/O Devices: Touch Screen, Communication devices such as modem…
(4)Storage Devices: A place that keeps program files and related data.
※Differences between Storage and Memory:
i. There’s more room in storage than in memory.
ii. Contents are retained in storage when the computer is turned off, whereas that in
memory disappear.
iii. Storage devices operate much slower than memory chips.
A. Megnetic Storage:
i. The devices that holds a disk is called a disk drive.
Hard Disk(Hard drive), Diskette (Floppy Disk)…
B. Optical Storage: Devices that use laser to read or write data.
i. The CD-ROM drive is the most common type of optical storage device.
ii. A CD-R drive can write and read data from CD-R disc, while a CD-RW can
rewrite data on CD-RW disc.
iii. An increasingly popular data storage is the Digital Video Disc(DVD), which can hold minimum of 4.7GB and as much as 17GB.
4. Softwares:
(1)System Software: Programs that control the computer’s hardware or help the computer runs more efficiently.
A. Operating System: Telling the computer how to use its components.
i. User’s request is handled by the operating system.
B. Network Operating System: Allowing computers to communicate and share data across a network.
C. Utility: Programs that make the computer system easier to use or perform highly specialized functions.
(2)Application Software: Programs that tell the computer how to accomplish specific tasks.
5. Data: Pieces of information, which doesn’t make sense themselves.
i. Computerized data is digital, meaning that it has been reduced to digits or numbers.
ii. A file is a set of data that has been given a name. Files that can be opened or used are
often called documents.
6. Users: A user’s role is as following:
(1)Setting up the system
(2)Installing software
(3)Running programs
(4)Managing files
(5)Maintaining the system
7. Userless Computer: Computers that require no human interaction.
i. Userless computers are typically controlled by their operating systems.
ii. The operating systems are programmed to perform specific tasks.
Abbreviations:
PC (Personal Computer) page5
PDA (Personal Digital Assistant) page7
I/O (Input/Output) page9
CPU (Central Processing Unit) page28
RAM (Random Access Memory) page29
ROM (Read-Only Memory) page29
CD (Compact Disc) page32
CD-ROM (Compact Disc Read-Only Memory) page32
CD-R (CD-Recordable) page32
CD-RW (CD-ReWritable) page32
DVD (Digital Video Disc) page32
2A. The Internet and the World Wide Web
1. Internet’s history:
(1)ARPANET(1969): Network that connects universities and defense contractors.
i. It allows people in remote locations to share scarce computing resources.
ii. Computers are connected by the form of telephone lines.
iii. Its host computers provide file transfer and communication services and give
connected systems access to the network’s high speed data lines.
(2)NSFnet(Mid-1980s): Network for academic purposes.
i. NSF established 5 supercomputing centers for networking.
ii. NSFnet is a new, higher-capacity network.
iii. The link between NSFnet and ARPANET and other networks are called Internet.
iiii . No permission for conducting private business.
(3)Early 1990s:
i. Several telecommunications companies built their own network backbones that used the same set of networking protocols as NSFnet.
ii. Not limited by NSFnet’s restrictions, so it was used to distribute business and commercial information.
2. To connect to the Internet, users have to connect their modem to a telephone line or other connections and set up an account with an Internet service provider(ISP), which provides local or regional access to the Internet’s backbone.
3. World Wide Web(WWW)(1989): Network that “link” documents stored in different locations.
4. Hypertext system: A way to manage large collections of data.
i. Hypertext Transfer Protocol(HTTP): Protocol that support hypertext documents.
ii. Hypertext Markup Language(HTML): Language that allows hypertext links(hyperlinks,
links)
iii. A hypertext document is commonly called web page, and a collection of related web pages is called a web site.
iiii. Copying a page onto a server is called publishing.
5. A web browser (browser) is a application software finding hypertext documents on the Web.
6. Uniform Resource Locator (URL): A format of Internet address.
Type://address/path
7. Helper applications (Plug-in applications) assist the browser.(Flash, RealPlayer…)
8. A popular media sharing technology is streaming audio/video.
9. Web-based search tools:
A. Directories: Search by selecting categories of subject matter.
B. Search Engines: Search by typing one or more keywords.
C. Metasearch Engines: Use multiple search engines simultaneously.
2B. Email and Other Internet Services
1. Electronic mail (E-mail) is the only service used more frequently than the Web.
i. Not a real-time communications system.
2. The most common way to create, send, and receive e-mail is by using an e-mail program (e-mail client) and Internet connection through an ISP or LAN.
3. An unique e-mail address enables other users to send messages to you and enables you to send messages to others.
4. Any sent message is stored on a mail server, often called POP (post office protocol) servers, which use the post office protocol.
5. Listserv systems allow users on the list to post their own messages to discuss with the groop.
6. Other features of the Internet:
(1)News: A public bulletin board.
i. A thread is referred as linked articles.
ii. The most common way to participate in newsgroups is by using a newsreader
program.
iii. A newsreader program obtains articles from a news server, which uses the network news transfer protocol (NNTP).
iiii. A newsgroup’s name begins with the domain, follow by words that describe the topic.
(2)FTP (File transfer protocol): An Internet tool used to copy files from one computer to another.
i. A FTP site is a collection of files, which is housed on an FTP server.
ii. Public FTP archives permit anyone to copy files by using FTP client software.
(3)Internet Relay Chat (IRC)(Chat): Real-time communication with other users.
i. IRC is a multi-user system where people join different channels, which are discussion groups.
(4)Instant Messaging (IM): A way to chat privately.
i. Using IM software, one can create a buddy list, for who one wants to chat with.
(5)Online Services: A company that offers many Internet services.
(6)Peer-to-Peer (P2P) Services: A distributed network that requires no central servers to
communicates different computers.
Abbreviations:
ARPA (Advanced Research Projects Agency) page50
NSF (National Science Foundation) page50
ISP (Internet Service Provider) page52
WWW (World Wide Web) page52
HTTP (Hypertext Transfer Protocol) page53
HTML (Hypertext Markup Language) page53
URL (Uniform Resource Locator) page55
POP (Post Office Protocol) page78
NNTP (Network News Transfer Protocol) page82
FAQ (Frequently Asked Questions) page82
FTP (File Transfer Protocol) page83
IRC (Internet Relay Chat) page84
IM (Instant Messaging) page85
Sysop (System Operator) page86
P2P (Peer-to-Peer) page86
3A. Using the Keyboard and Mouse
Ignored…
3B. Inputting data in Other Ways
1. Devices for the hand:
(1)Pens (Stylus)
i. Pen-based computers are commonly used for data collection.
(2)Touch Screen
(3)Game Controller: Joystick, Game pad…
2. Optical Input Devices:
(1)Bar Code Readers
(2)Image Scanner
(3)Optical Character Recognition (OCR)
3. Audiovisual Input Devices:
(1)Microphones:
i. For microphone input, user must need a microphone and a sound card inside the computer.
ii. Digitizing process means to translate analog audio signals into digital codes.
(2)Other Audio Input Devices: Require a sound card.
(3)Video Input: PC video camera, Webcam, Video capture card…
(4)Digital Cameras
Abbreviations:
RSI (Repetitive Stress Injuries) page115
OCR (Optical Character Recognition) page126
MIDI (Musical Instrument Digital Interface) page130
4A. Video and Sound
1. Monitors:
i. Two factors determining the quality of image is monitor itself and the video controller.
(1)Monochrome Monitors: Display only one color against a contrasting background.
(2)Grayscale Monitors: Display varying intensities of gray against an off-white background.
(3)Color Monitors: Display between 16 colors to 16 million colors.
2. CRT Monitors: An electron gun shoots a beam of electrons through magnetic coil that aims at the front of the monitor, hitting chemicals called phosphors that coat the screen, making phosphors glow.
i. The smallest number of phosphor dots the gun focused is called a pixel.
ii. The three guns represent three additive colors: Red, Green, Blue.
iii. Electric guns scan from left to right, up to down.
iiii. CRT monitors contain shadow masks, while the holes in their mesh align the beams.
(1) Advantages: They provide bright, clear pictures at a relatively low cost.
(2) Shortages: They take up desktop space and can be difficult to move, and they require a lot of power to run.
3. Flat-Panel Monitors:
A. Liquid Crystal Display (LCD): Liquid crystal is normally transparent but becomes opaque when charged with electricity.
※Shortage: Limited viewing angle, darker light.
i. Passive Matrix LCD: Transistors are activated by each row and column.
※Shortage: Submarining, means the disappearing of quick-moving objects.
※Dual-Scan technology helps soothe the problem.
ii. Active Matrix LCD: Transistors are individually activated.
※Using Thin film transistor (TFT) technology.
4. Other Types of Monitors:
(1)Paper-white displays: High contrast between background and text.
i. LCD version of paper-white display is called page-white display.
(2)Electroluminescent displays (ELDs)
(3)Plasma displays
5. Comparing Monitors:
※Standard CRT monitors have some distortion problem.
(1)Size: Measured in inches, diagonally. (Big)
(2)Resolution: Determined by the number of pixels on the screen. (High)
(3)Refresh Rate: The number of times per second that the electron guns scan every pixel on
the screen, measured in Hertz (Hz). (High)
(4)Dot Pitch: Distance between the like-colored phosphor dots of adjacent pixels, measured in millimeter (mm). (Small)
6. Video Cards: Contains the video-dedicated memory and circuitry necessary to send information to the monitor for display.
i. Video controllers feature their own built-in microprocessors, and its speed determines the refresh rate.
ii. Video controllers also feature their own built-in video RAM (VRAM).
7. Data Projectors: Projects the video output onto external surface.
i. Newer models use digital light processing (DLP) technology, which can display clear images in normal lighting room.
8. Sound System:
(1)Sound Card: A circuit board that converts sound from analog to digital form, and vise versa.
(2)Headphones and Headsets
4B. Printing
1. Commonly Used Printers:
(1)Impact printer: Create image by using pins or hammers to press inked ribbons against the paper.
(2)Nonimpact printer: Use other means to create an image.
2. Dot Matrix Printers:
i. Creating images by using print head, which contains a cluster of short pins arranged in columns.
ii. The speed of dot matrix printers is measured in characters per second (cps)
iii. Can produce sheets of plain text very quickly.
A. Line Printers: Work like dot matrix printers, but uses a special wide print head that can print an entire line of text at one time.
B. Band Printers: Feature a rotating band embossed with alphanumeric characters.
3. Ink Jet Printers:
i. Creating images directly on the paper by spraying ink through tiny nozzles.
ii. Cost relatively low to laser printers.