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Stanford CS Midterm 1
Computers, HTML, CSS
114
Computer Science
Undergraduate 3
05/04/2010

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Cards

Term
Hardware- Processing
Definition
Central Processing Unit; responsible for carrying out the instructions contained in a computer program
Term
Hardware- Storage
Definition
Most information is stored in one of two places--the main computer memory or the computer hard disk.
Term
Main Computer Memory
Definition
RAM stores information on computer chips using a series of electronic switches.
Switches are either turned on or off
Information in main memory is lost when the computer is turned off.
Main computer memory is relatively expensive.
Term
Computer Hard Disk
Definition
Information stored on the computer hard disk is stored magnetically.
Retained even when the power is turned off.
Cheaper per byte.
Term
Input/Output
Definition
Devices used to get information from the user or to present infomration to the user.
Monitor, keyboard, mouse...
Exgternal devices (peripherals--printers and scanners)
Term
Software
Definition
Application Software and System Software
Term
Application Software
Definition
Programs used for productivity or entertainment purposes
Term
System Software
Definition
Used to manage the computer
Operating system
Windows and MacOS
Graphical interface for the user allowing her/him to start and stop programs and manage files
Term
Program Execution
Definition
CPU can only execute instructions that are in main memory
Instructions copied onto main computer memory from hard disk
Saving--copies current data specific to task onto hard disk
Term
Processing
Definition
CPU is bottleneck which limits the overall performance of the computer
Main CPU and other processor specifically for graphics
Term
Multiprocessing
Definition
Used to overcome the processor bottleneck\Break down the problem our computer is working on into separate tasks which can be executed by multiple processors working simultaneously
Term
Binary Number System
Definition
Each switch represents a single binary digit (BIT)
Byte= Eight bits
Words= Organized set of bytes
Address= Reference number for each individual byte
Term
Address
Definition
Reference number for each individual byte
Term
RAM
Definition
Random Access Memory
Computer can change contents of RAM at any point
Term
ROM
Definition
Read Only Memory
Information cannot be changed
Switches have been glued either on or off
Negligible compared to RAM
Modern ROM can be changed (Flash ROM)
Contents are still kept when the computer is turned off
Term
Cache Memory
Definition
Small amount of memory that is even faster than main memory
Stores information that is frequently accessed
Term
Virtual Memory
Definition
Extends the amount of apparent main memory by using a section of the hard disk which acts as if it were additional main memory

CPU can only access information in main memory

Allows us to run more programs at once than we would normally be able to
Term
Thrashing
Definition
Programs run slowly and the hard disk churns due to excessive switching between programs and lack of real main memory
Term
Serial and Parallel Connections
Definition
Serial--connection bits are sent through the connection one at a time
Parallel--multiple bits are passed through simultaneously over different wires in the connector

(Newer connections--single bits are faster speeds)
Term
Peripherals
Definition
USB (Universal Serial Bus)
USB 2.0
IEEE-1394 (Firewire)
Bluetooth
Wi-Fi
Term
Linking
Definition
anchor tag
end tag
href (hypertext reference)

Example:
URL
Term
Absolute Reference
Definition
Specify the name of the protocol, the name of the webserver and the name of the file which the web browser should retrieve
Term
Relative Reference
Definition
Used to create links between files which are located on the same webserver
It assumes that the webpage referred to is found at the same location as the current webpage
Term
Creating a relative reference to a file in another folder
Definition
Example:

.../index.html
Term
Absolute vs. Relative References
Definition
Relative references make a website more portable
Term
Linking to Mail
Definition
Term
Link Destinations
Definition

Term
Images
Definition
[image] All image tags require an alt attribute
Term
Image Formats
Definition
JPEG- Photographs
GIF- Non-photographic images
PNG- Non-photographic images (more advanced)
Term
Alignment of an image
Definition
align="value"

values include:
top
bottom
middle
left
right
Term
Image size
Definition
height and width attributes
pixels
percentages
Term
List Types
Definition
Unordered
Definition
Numbered
Term
Ordered Lists
Definition
    start tag
  • list item
  • Term
    Definition Lists
    Definition
    definition list
    definition term
    definition description
    Term
    Tables
    Definition
    Table header (instead of td)
    Start Table Table Row
    Table Data
    Term
    Adjusting tables
    Definition
    colspan (to make a cell span more than a single column)(use with td or th)
    rowspan
    width/height of cell (use with th or td or tr)
    Term
    Inserting comments
    Definition
    Term
    Divisions
    Definition
    used to create sections within an HTML document attributes: align (center, right, left)
    Term
    JPEG
    Definition
    24 bit color (like PNG)
    lossy
    Term
    GIF
    Definition
    256 color maximum
    effect of watching a movie by stringing many images together into a single file
    lossless
    Term
    PNG
    Definition
    alternative to GIF
    allows for semi-transparent images
    24-bit color (16.7 million colors)
    lossless
    Term
    Star network
    Definition
    Every computer is connected to a central hub computer
    Any computer except the central hub can fail without affecting others
    Term
    Network topology
    Definition
    The form in which the computers on a network are connected together
    Term
    Ring network
    Definition
    The computers are linked into a ring
    When a computer wants to send a message, it sends it to its neighbor on the right (counterclockwise)
    If one of the computers fails, messages won't be able to make it around the ring to their destination
    Term
    Bus network
    Definition
    Computers are connected directly to a central called a bus
    Contention issues--multiple computers may try to send messages out on the bus at the exact same time
    Term
    Connection mediums
    Definition
    Twisted pair cables (similar to phone line)
    Coaxial cables (similar to cable television line)
    Fiber optic cables
    Term
    LAN
    Definition
    Local area networks (small)
    Term
    MAN
    Definition
    Metropolitan Area Networks (within a city or small region)
    Term
    WAN
    Definition
    Wide Area Networks (connects states, nations or even continents)
    Term
    Bridge
    Definition
    Connects together the same type of network technology
    Term
    WAN
    Definition
    Wide Area Networks (connects states, nations or even continents)
    Term
    Bridge
    Definition
    Connects together the same type of network technology
    Term
    Router
    Definition
    Special-purpose device that connects different types of technology
    Term
    Bandwidth
    Definition
    The range of frequencies in the electromagnetic spectrum that a medium can use to send information
    Broadband or Narrowband
    Term
    Telephone/Modem (POTS)
    Definition
    Connects a computer to another computer using the standard telephone service
    Uses a modem (converts from bits and bytes to an analog tone that can be transmitted over a telephone line)
    56 kilobits per second maximum
    Term
    Digital Subscriber Line
    Definition
    DSL
    Takes the unused bandwidth from copper telephone wires and uses it to transmit digital information
    Speed varies according to subscriber's distance from the telephone company's central office
    Term
    Cable Modem
    Definition
    Uses the cable used to bring television
    1.5 megabits per second or faster
    Term
    Ethernet
    Definition
    Slightly oversized telephone cable
    100 megabits per second
    Term
    T1, T3, OC3, OC12
    Definition
    Other types of connections
    Term
    Protocols vs. Programs
    Definition
    Protocol is a specification
    Defines how programs written to support the protocol should act
    More than one program can support the same protocol
    Term
    Internet Protocol Layers
    Definition
    Application layer
    Transport layer
    Network layer
    Physical/Data layer
    Term
    Application Layer
    Definition
    Defines actual control and data transfer needed for specific applications
    Wide range of different protocols for e-mail, web, IM
    Term
    Transport Layer
    Definition
    Builds on Network Layer
    Supports error detection and correction
    Provides transport of unlimited amounts of data
    Term
    Network Layer
    Definition
    Responsible for transferring data across the Internet
    No error checking
    Data limited to small size "packets"
    Term
    Physical/Data Layer
    Definition
    Defines physical connections between computers in network
    Determines how 0s and 1s are sent on medium (eg voltage levels)
    Term
    IP numbers/addresses
    Definition
    Every computer on the Internet has its own
    Assigned when a computer is first connected to the Internet
    Four numbers between 0 and 255 separated by dots
    Used by network layer (help route messages on the Internet)
    Term
    MAC addresses
    Definition
    Used at physical/data layer
    Allocated on the basis of which company manufactured a particular card
    Do not provide any information as to where the computer is located
    Routing of messages within an individual LAN
    Term
    Packet Switching vs. Circuit Switching
    Definition
    Telephones are circuit switching based (quality of connection remains constant)
    Internet is packet switching based (all circuits shared)
    Term
    HTML
    Definition

    Hypertxt Markup Language

    computer language used to define layout and formatting information on webpages;

    not a program

    Term
    Syntax Rules
    Definition
    like grammar rules used in HTML, determine if sentance/construct is legal
    Term
    Semantic Language
    Definition
    Vocabulary of HTML
    Term
    Markup
    Definition
    We take unformatted text and mark ip up for display on a computer; HTML is a markup language-- markup is done in a standard text editor
    Term
    WYS/WYG
    Definition
    Word, unlike a standard text editor, displays text as it is seen. There is no need for markup, all formatting is done within the file
    Term
    Tags
    Definition

    HTML tags tell the computer how to display a webpage.

    They often work in pairs

    Start tag <>

    End tag </>

    Start & end tags create a container for text

     

    Term
    Attributes
    Definition
    Can be added to tags to provide additional information
    Term
    Element
    Definition

    The "container" includes

    start tag, end tag, and contents

    Term
    Colors
    Definition

    16 standard colors for HTML; 16.7 million custom colorscreated w/ hexidecimals

    Red, Green, Blue

    Term
    File Extensions
    Definition

    .xls (excel)

    .doc (word document)

    .txt (text)

    .html (what html must be saved as to open!)

     

    Term
    Nesting Rules
    Definition

    Part of syntax rules-- sets of formatting tags can be used together, but must be properly nested

     

    <b>an example of <i>nesting</i><b>

     

    (must be closed in order!!!)

    Term
    In-Line Tags/Text Level Tags
    Definition

    tell text what to do

    bold <b> 

    italics <i>

    underline <u>

    inc font by 1 <big>

    dec font by 1 <small>

    changes size, color of text or font face <font>

    Term
    Block Level Tags
    Definition

    control larger amounts of text

    paragraph <p>

    line break in text <br />

    headers <h1>...<h6>

    horizontal line <hr />

     

    Term
    Computer language
    Definition
    formal language that defines how humans communicate with a computer
    Term
    File level tags/HTML tags
    Definition

    These are necessary for all HTML pages!

    start of XHTML <?xml>

    <html> all contents of html

    <head> used by browser, not displayed

    <title> listed IN head, displayed in web title bar (can't contain formatting)

    <body> actual content-- including background/text color

    must close each of these!

    Term
    JavaScript
    Definition
    Computer programing language associated with HTML
    Term
    Debugging
    Definition
    Getting rid of bugs/errors so source code can validate and work properly
    Term
    HTML Table & Separating into Multiple Columns
    Definition
    Columns created with <table> and single <tr> row and one <td> table data for each column
    Term
    Navigation & Advertising Sidebars
    Definition

    Created with table columns! ie <td> within a <tr>

    Navigation usually on left.

    Advertising on right.

    Term
    Vertical Placement of buttons & ads
    Definition
    Each button/ad has its own <tr> with a single <td>
    Term
    Blank Space (vertical)
    Definition
    empty <td> w/ specified heighth
    Term
    Blank Space (horizontal)
    Definition
    empty <td> with specified width
    Term
    Incremental development
    Definition
    Used for complex projects; built in steps/stages & checked before going on
    Term
    Background for webpage
    Definition

    The <body> tag has a background attribute that allows to set image as background of body;

    if not big enough, repeats!

    Term
    TCP
    Definition

    Transmission Control Protocol

    Provides application built on top of it with a direct connection between any two computers on the Internet

    Implementation of the TCP protocol takes data sent by an application and breaks it into chunks small enough to fit into individual IP packets

    The TCP implementation sends the packets through the Internet

    TCP numbers the packets and reorders them if necessary when they are received

    Automatically resends a copy of a packet if it is lost

    Associated with specific applications

    Term
    IP
    Definition

    Does not identify which application running on the original computer sent the message or which application on the recipient computer should receive the packet

     

    Term
    SMTP
    Definition

    Simple Mail Transfer Protocol

    Used to send mail from one computer to another

    E-mail is usually sent to a mail server computer

    Term
    Hostnames
    Definition

    An alternate naming scheme supported by application level programs

    ex: www.whitehouse.gov

    A computer can have multiple hostnames (usually only one)

    Converted into IP number by computer

     

    Term
    Client/Server
    Definition

    Model of computing

    Two different types of computers participate: client computers and server computers

    Client comps: multi-purpose

    Server comps: dedicated single-purpose; sends webpages to client comps upon request

    Term
    Peer-to-Peer
    Definition

    Two or more computers cooperate to carry out a task

    Neither computer is in charge

    Ex: Chat application

    Requires fewer resources

    Reduces legal liability for file sharing programs

    Term
    Hypertext
    Definition

    Text in one part of a document may be connected to text in other parts of the document via links

    Replacement for books

     

    Term
    multi-column w/ header
    Definition

    header can be made in body before <table>

    w/ <h1 align="center"><font size="" face="">...</h1>

    or an image can be added, but use the <div> tag to center!!

    <div align="center">

    <img scr="blah.gif" alt="blah"></div>

    Term
    Ads as images in ad column
    Definition

    can hae multiple rows w/ images in <td>

    remember to set border="0" on ad's <img> tag

    provide height and width for better display

    Term
    Sidebar summary
    Definition

    -single row tables w/ multiple columns a <td> for main and a <td> for sidebar!

    -remember valighn="top"

    -fix width attribute within <td> tab

    -placement within a sidebar can be controlled w/ inner <table> contained in sidebar <td>

    Term
    Navigation sidebar (multi-page)
    Definition

    -home should be saved as index.html, can be copied

    -must organize files first on comp (location scheme)

     

     

    Term
    Example navigation tab html code
    Definition

    <tr><td><a href=index.html">

    <img src="buttons/home-button.gif" alt="home" border="0" width="x" height="x" /></a></td></tr>

    Term
    URL
    Definition

    Uniform resource locators

    used to identify specific files, web pages, and other information at a much more detailed level than that provided by hostnames and IP numbers

    Begins with an identifier determining what kind of information is being referenced

     

    Term
    Changing font notes
    Definition

    <font> tags are limited to in-line text;block elements illegal

    so:

    <p><font face"sans-serif" size="4"></font></p>

    Term
    Adding background images
    Definition

    <body background="images/background.gif">...</body>

    browser repeats pattern, vertically...so play w/ gif

    Term
    HTTP
    Definition
    Hypertext Transfer Protocol
    Term
    The Request Line
    Definition

    GET-most common request, requests that a webserver send a file

    HEAD-requests information on a file

    POST-requests the information that a user has entered into the webpage form, webserver sends back the results

    Term
    The Status Line
    Definition

    example: HTTP/1.1 200 OK

    ERRORS are displayed here

    Term
    Headers
    Definition
    Consists of a header type followed by a colon ':' followed by a corresponding value
    Supporting users have an ad free experience!