Final CSC101 Review Sheets
Chapter 11 Study Guide
Data used to be stored on magnetic tape Sequential storage o Data is stored and retrieved in sequence o Less expensive o Searching is SLOW o Examples: Floppy disk Magnetic Tape Direct access storage o the computer can go directly to the information desired o Data retrieved using KEY o Uses File Allocation Table (FAT) o More expensive and complex o Searching is FAST o Examples: Hard Disk CD-ROM DVD What is a database? o Electronic collection of related data o Helps us organize data o Makes it easy to access data for use When is a database needed? o You need a database o Any time complex information needs to organize or if more than one person needs to access it. o For example, When you enrolled in college you provided information about yourself (name, address, classes selections) The school also keeps track of what dorm your in and how much money you have on your gull card. Database Management Systems o DBMS - programs that control the structure of a database and access to the data o Advantages of a DBMS Provide data centralization Reduced data redundancy Don't need to repeat the same information over and over Increased security Information can be limited to select users.
CSC101 Final Review Sheets Ease of data maintenance There are procedures for adding, deleting and modifying records. Backup utilities Validation Checks o Application software designed to capture and analyze data o Four main operations of a DBMS are: Creating databases and entering data Viewing and sorting data Extracting data Outputting data Advantages of using Databases: o Store and retrieve large quantities of information o Improved data integrity o Data is accurate, consistent and up to date! o Enable information sharing o Allow for flexible use of data Database Terminology o Field Category of information displayed in columns Each field has a field name o Data types Text Numeric Computational Date Memo Object Hyperlink o Record A group of related fields o Table A group of related records o Primary key A field value unique to a record Different forms of data o Numbers Mathematical values Use with Mathematical Functions ( +, -, *, / ) Integers or Whole numbers 0, 1, 350, 2000, 1000000 Real Numbers or Floating Point 0.0, 5.0, 3.1418, 89.25, 1000.12345 o Alphanumeric Characters
CSC101 Final Review Sheets Letters, numbers, punctuation marks ASCII Code represents each character We can't perform mathematical function with these numbers. They are just text! 1600 Pennsylvania Avenue Washington, DC 20500
Key Field o A key field UNIQUELY identifies a record for processing and retrieval Database Types o Relational databases o Organize data in a table o Link tables to each other through their primary keys o Object-oriented databases o Stores data in objects o Handles unstructured data o Object-relational databases o A hybrid of a relational and object-oriented database 1. Creating Databases and Entering Data o Create field names: Identify each type of data Data dictionary Create individual records: Key-in Import o Data Validation Validation Process of ensuring data entered into the database is correct (or at least reasonable) and complete Validation rules Range check Completeness check Consistency check Alphabetic/numeric checks 2. Viewing and Sorting Data o Browse through records o Sort records by field name 3. Extracting or Querying Data o Query A question or inquiry Provides records based on criteria Structured query language (SQL) 4. Outputting Data
CSC101 Final Review Sheets o Reports: Printed Summary data reports o Export data Relational Database Operations o Relational databases organize data into tables based on logical groupings o Relationships are links between tables with related data o Common fields between tables need to exist o Normalization of data (recording data once) reduces data redundancy Data Storage o Data warehouses A large scale repository of data Organizes all the data related to an organization Data is organized by subject Populating Data Warehouses o Source data Internal sources Company databases, etc. External sources Suppliers, vendors, etc. Customers or Web site visitors Clickstream data Data Staging o Data staging Extract data from source Reformat the data Store the data o Software programs/procedures created to extract the data and to reformat it for storage Data Marts o Small slices of data o Data of a single department Managing Data: Information Systems o Information systems Software-based solutions used to gather and analyze information o Functions performed by information systems include Acquiring data Processing data into information Storing data Providing output options Information Systems Categories o Office support o Transaction processing
CSC101 Final Review Sheets o Management o Decision support
Office Support Systems (OSS) o Assist employees in day-to-day tasks o Improve communications o Microsoft Office Transaction Processing Systems (TPS) o Keeps track of everyday business activities o Batch processing o Real-time processing Management Information Systems (MIS) o Provides timely and accurate information for managers to make business decisions Detail report: Transactions that occur during a period of time Summary report: Consolidate detailed data Exception report: Show unusual conditions Decision Support Systems (DSS) o Help managers develop solutions for specific problems Data Mining o Process by which data are analyzed and investigated o Objective is to spot patterns or trends within the data Data Mining Methods o Classification Define data classes o Estimation Assign a value to data o Affinity grouping or association rules Determine which data goes together o Clustering Organize data into subgroups o Description and visualization Provides a clear picture of what is happening Databases and Information Systems Data used to be stored on magnetic tapes. -Hard disk are then used to access data randomly.
CSC101 Final Review Sheets Sequential storage v. Direct access storage (hard disks) -sequential is less expensive and slow -direct access (FAT) faster and more expensive -ex. of sequential: floppy disk -ex. of direct access: CD-ROM What is a Database?Electronic collection of related data Helps us organize data Makes it easy to access data for use -Once data is collected and organized in a database it turns into information Database Management System (DBMS) Programs that control the structure of a database and access to the data -Provide data centralization Reduced data redundancy -Don't need to repeat the same information over and over Increased security -Information can be limited to select users. Ease of data maintenance -There are procedures for adding, deleting and modifying records. -Backup utilities -Validation Checks Advantages -Store and retrieve large quantities of information -Improved data integrity -Data is accurate, consistent and up to date! -Enable information sharing -Allow for flexible use of data Field- columns Record= group of fields Primary Key= unique to a record Data comes in different forms: numeric, alpha Database Types: Relational databases Organize data in a table Link tables to each other through their primary keys Object-oriented databases Stores data in objects Handles unstructured data Object-relational databases A hybrid of a relational and object-oriented database Four main operations of a DBMS are: 1. Creating databases and entering data
CSC101 Final Review Sheets 2. Viewing and sorting data 3. Extracting data 4. Outputting data Query : A question or inquiry Provides records based on criteria Structured query language (SQL) Data staging Extract data from source Reformat the data Store the data Information systems Software-based solutions used to gather and analyze information Office Support System- ex. Microsoft Office Data Mining Process by which data are analyzed and investigated Objective is to spot patterns or trends within the data ======================================================
Chapter 8
Advantages and limitations of mobile computing Mobile computing devices: Pagers Cell phones PDAs MP3 players Synchronizing mobile devices with computers Tablet PCs Laptops
Mobile Computing: Advantages Convenience Boost productivity Communicate with others anywhere Access to electronic information Limitations Expensive Battery life Small screen display Slow Internet speed
CSC101 Final Review Sheets Mobile Computing Devices: Pagers Cellular phones MP3 players Personal digital assistants Tablet PCs Laptop computers Paging Device: Small wireless devices that receive numeric messages (phone numbers) Recent technological advancements enable: Voice paging: Receiving voice messages Alphanumeric paging: Receiving numeric and text messages Two-way paging: Receiving and sending text messages Cell Phones: Full-featured communication and information storage devices Features include: Auto-redial Call timers Voice-mail Voice-activated dialing Internet access Text messaging Personal information management Cell Phone Hardware: Microprocessor (CPU): Coordinates data between components Runs the operating system Memory: ROM stores the operating system Internal memory chips store: Contact data Ring tones Images Small application programs Input devices: Microphone Keypad Graffiti pad Touch-screen Digital camera Output devices: Speaker LCD display
CSC101 Final Review Sheets Cell Phone Features: Text messaging: Short Message Service (SMS): Send messages up to 160 characters Multimedia Message Service (MMS): Send text, sound, images, and video clips Internet connectivity: Wireless Internet service provider Maximum speed of 14.4 Kbps Micro-browser software MP3 Players: MP3: Format for storing music MP3 player: A small device that stores and plays music Storage space determines the number of songs stored: Memory chips 64 MB to 256 MB Hard drive up to 40 GB Sampling rate also affects number of songs stored MPS Flash Player: Used to add additional memory to MP3 players Types of flash memory: Compact Flash: 64 MB to 1 GB Multimedia (MMC) and SmartMedia: 128 MB Secure Digital: 512 MB Sony Memory Stick: 128 MB PDA: Small devices that store digital information Known as palm computers or handhelds PDA hardware includes: CPU Operating system Storage capabilities Input/output devices Ports PDA Memory and Storage: ROM stores the operating system and the basic programs RAM stores additional applications and data Flash memory is used for additional storage Laptop Hardware: Hard drives
CSC101 Final Review Sheets RAM Hot-swappable bays: Remove a drive and replace it with another type Keyboard Built-in mouse LCD displays Laptop Op. Systems: Same operating systems as those found on desktops Power management: Shuts down the hard drive Turns off the monitor Puts the computer into standby model
Chapter 1: Data vs. Information -Data is raw facts and figures that are processed into information -Information is data that has been summarized for use in decision making Data: raw facts and figures that are processed into information Information: data that has been summarized or otherwise manipulated for use in decision making Bits :Binary digit 0 or 1 Byte: 8 Bits ASCII: each byte represents a letter, number or character Hardware: system unit and peripheral devices Chapter 2: Input/ Output -Input devices: devices used to enter information or instructions into the computer ex. Keyboard, scanner, mouse, microphone, digital camera Input devices: used to enter information or instructions into the computer. EX. Keyboard, mouse, microphone, scanner, camera -Output devices: enable us to see or hear the processed information; retrieving Information from the computer -ex. Printer, monitor, speakers, headphones Output devices: used to retrieve information from the computer ex. Video, sound, speakers, print. Chapter 2 and 6: Primary storage/ Secondary Storage -Primary storage: known as the main storage component for the computer it is stored for quick access by the computers processor; sometimes RAM is used in place of primary storage; RAM is volatile meaning it is erased when the computer is turned off Secondary storage: hard disk is the main form of secondary storage on a computer and it is non-volatile Primary Storage :
CSC101 Final Review Sheets o RAM (random access memory): temporary storage (volatile) , Linux requires less RAM then windows, you can add RAM to you computer o Virtual memory: free hard disk space used to extend the capacity of RAM Secondary Storage: o Hard Disk drive: Stores data and programming instructions, this is permanent (non volatile storage) o Floppy Disk: o Zip Disk: o CD's: optical storage o DVDs: optical storage o Flash Drive o Flash Memory card Magnetic Storage: o Metal platters = hard disks o Plastic film = floppy disks and zip disks o Sector: Single section o Track: each ring around the CD o Cluster: group of sectors ========================================================== Circuit Switching Transmitter has full use of the circuit unit all data has bee transmitted and circuit is terminated. o Best for voice o Not efficient for sending data. o Dedicated line o Line is in use even when nothing is being sent. (e.g. Putting a call on hold) o Path of signal is determined before communication begins Packet Switching Electronic messages are dividend into packets of fixed length (1,000 1,500Bytes). Then transmitted over wide area network to destination o Travels the most expedient route o Best for Data o TCP/IP is a packet Protocol o Efficient for sending data o Line in use only when data is being sent o Communication path is determined for each packet. packet Each contains: 1. Sender's address 2. Receiver's address 3. Number of packets being transmitted 4. Packet Number
CSC101 Final Review Sheets Operating Systems Real Time Operating System - Systems with a specific purpose and a certain result Single-Task Operating Systems - Perform one task at a time: PDA Multi-Task Operating System - Executing 2 or more programs at the same time by 1 user. OS executes a small portion of each program giving each a turn until they're done. Multi-user Operating Systems - Allow access to the computer system by more than one user, known as network operating systems Some well known operating systems - Microsoft Windows, MAC OS, UNIX, Linux Microsoft Windows Market leader 90% market share MAC OS First operating system with point-and-click technology (Graphical User Interface) Excellent in: Graphics display Processing capabilities System reliability Document recovery Fewer software applications UNIX Multi-user, multitask operating system Used primarily with mainframes Linux Open-source operating system Based on UNIX Stable system Free May be downloaded through the Internet What the Operating System Does Provides user interface Manages the CPU Manages memory Manages hardware Coordinates application software with the CPU The User Interface Enables you to interact with the computer Types of interfaces: Command-driven interface Menu-driven interface, Graphical user interface
=========================================================== Bit Binary Digit Byte group of 8 bits Decimal System Base 10 10 different digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) Organized into columns (thousands, hundreds, tens, ones) (1*1000) + (2*10) + (4*1) =1024
CSC101 Final Review Sheets Binary System Base 2 2 different digits (0, 1) Numbers Organized into Columns (eights, fours, twos, ones)
Eights 2
3
Fours 2
2
Twos 2
1
Ones 2
0
1
0
1
1
3 + 1 + 0 = 11 2 2 2 (1*8) + (1*2) + 1 =11 Each bit corresponds to a power of 2 20 = 1 24 = 16 21 = 2 25 = 32
28 = 256 29 = 512 210= 1024
22 = 4 23 = 8
Decimal to Binary
26 = 64 27 = 128
If a bit is turned on add that amount to the total. Divide your number by two. Keep track of your remainders. Every time you have a remainder of 1, this coincides with a binary 1. No remainder, a binary 0. Continue until you've reached 0. From bottom to top, write down the numbers that you've gotten for remainders.
Our number is 10 1. 10 / 2 = 5 r 0 2. 5 / 2 = 2 r 1 3. 2 / 2 = 1 r 0 4. 1 / 2 = 0 r 1 5. Binary: 1010 (read bottom up) 6. Odd numbers always end in a 1. 7. Even numbers always end in a 0.
Converting Numbers from Binary to Decimal (and Decimal to Binary) Binary to Decimal The binary system has only 2 digits: 1 and 0 Binary numbers are organized into columns and each bit corresponds to a power of 2: 1 24 1 23 0 22 0 21 1 20
CSC101 Final Review Sheets Going from right to left, if a bit is turned on, add that amount to the total. A bit is turned on if it is a 1, so you add the amount that corresponds with the number 1's:
1 24 16
1 23 8
0 22 4
0 21 2
1 20 1
16 + 8 + 1 = 25 So, 11001 is 25 when converted to decimal Decimal to Binary Divide the decimal number by 2 Keep track of the remainders every time that you have a remainder of 1, it coincides with a binary 1. If there is no remainder, it coincides with a binary 0. Continue until you reach 0. Then, from bottom to top, write down the numbers that you got for remainders. If the number is 10: 10/2 = 5/2 = 2/2 = 1/2 = 5r0 2r1 1r0 0r1
Binary: 1010 Odd numbers always end in a 1. Even numbers always end in a 0.
Binary System
The word "binary" describes a system that has only two possible digits; 0 &1 . The reason for this, is that there are only two states an electrical circuit can be in. Known as on and off or 1 and 0, 1 for on and 0 for off. *Bit is short for Binary Digit
8 bits used to represent one character, digit, or other value
*Byte is a group of 8 bits to represent one character, digit, or other value Binary (meaning 'two') is the ones and zeros that computers use. By grouping 1's and 0's together, a computer, or electrical circuit can create letters numbers and 'True' or 'False. Every bit of info in a computer has a binary code assigned to it and the computer knows these, for example, the letter 'A' converts to '01000001' in binary.
CSC101 Final Review Sheets
How to convert binary to decimal ? To convert binary to decimal, we start from the right to the left of the binary chain and at each bit, we associate the value 2^(character number), the first bit being bit number 0. Note: 2^0 = 1 2^1 = 2 2^2 = 2 x 2 (2 times) 2^3 = 2 x 2 x 2 (3 times) . For 1 1 0 0 1 0 1 1 example: <-----------------------------------------power of 2: Value: 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 128 64 32 16 8 4 2 1
. The decimal value is the sum of the binary charaters times the powers of 2. . For the example above: Result = 1 x 1 + 1 x 2 + 0 x 4 + 1 x 8 + 0 x 16 + 0 x 32 + 1 x 64 + 1 x 128 = 203 The minimum value is all bits set to "0" which is "0" in decimal and the maximum value for 8 bits (a byte) is all bits set to "1" which is "255" in decimal. Another example Example: 1111 1111 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255
Converting Decimal to Binary (A little more difficult)
-Divide your number by two. -Keep track of your remainders. -Every time you have a remainder of 1, this coincides with a binary 1. No remainder, a binary 0. Continue until you've reached 0. From bottom to top, write down the numbers that you've gotten for remainders.
CSC101 Final Review Sheets
Let use the 10 for an example: 1.) 10 / 2 = 5 r 0 2.) 5 / 2 = 2 r 1 3.) 2 / 2 = 1 r 0 4.) 1 / 2 = 0 r 1 5.) Binary: 1010
Desktop operating system. The combination of operating system and processor is referred to as a computer's platform. o For example, Microsoft Windows operating systems are designed to coordinate with a series of processors from Intel Corporation and AMD (Advanced Micro Devices) that share the same or similar sets of instructions. However, Apple Macintosh operating systems work primarily with processors from Motorola and IBM designed specifically for Apple computers. The three most used desktop operating systems are Windows, Mac OS, and Linux. Virtual memory Due to RAM has limited capacity. The instructions and data are stored on the hard drive when RAM is full. It is called virtual memory. Therefore, when there isn't enough room in RAM for the OS to store the required data and instructions, it borrows room from the hard drive. The process include the following steps: Virtual memory optimizing RAM storage by borrowing hard drive space. Swap file. When more RAM space is needed, the OS swaps out from RAM the data or instructions that have not been recently used and moves them to a temporary storage area on the hard drive Paging. If the data and/or instructions in the swap file are needed later, the OS swaps them back into active RAM and replaces them in the hard drive's swap file with less-active data or instructions. Thrashing. Finally, when your computer will become sluggish as it is forced to page more and more often. The solution to this problem is to increase the amount of RAM in your system so that you can avoid it having to send data and instructions to virtual memory. Circuit Switching o Transmitter has full use of the circuit until all the data has been transmitted and the circuit is terminated Think phone service. When you call a friend, you have a dedicated circuit at your disposal until you hang up o NOT efficient for sending data. o Dedicated Line
CSC101 Final Review Sheets o Line is in use even when nothing is being sent o Path of signal is determined before communication begins Packet Switching o Electronic messages are divided into packets of fixed length (typically 1,000 1,500 Bytes) Then transmitted over a wide area network to their destination The packet travels the most expedient route o Best for Data o TCP/IP is a Packet Switching Protocol o Line in use only when data is being sent. o Communication path is determined for each packet. o Benefits: Can handle a large volume of traffic Allows more to share users to share network Good method for sending data over large distances. Packet Loss o The number of packets that are lost on the way to the destination computer. o Message may be ok with some lost packets. o Receiving computer may decide to ask for sending computer to re-transmit the message. Vocabulary /Infoo Packet - a fixed-length block of data for transmission. o Best for voice - circuit switching. o Best for data - packet switching. o Ping time - the amount of time it takes a packet of data to make a round trip between two computers.
TERMS:
1. Application Software: The set of programs on a computer that helps a user carry out tasks such as word processing, sending e-mail, balancing a budget, creating presentations, editing photos, taking an inline course, and playing games. 2. FAT: Stand for File Allocation Table. An index of all sector numbers that the hard drive stores in a table to keep track of which sectors hold which files. 3. Disk Fragmentation: The scattering of parts of a file throughout a disk, as when the operating system breaks up the file and fits it onto the spaces left vacant by previously deleted files. 4. Binary System: The number system used by computers to represent all data. Because it includes only two digits (0 and 1), the binary number system is also referred to as the base 2 number system. 5. Protocols: A set of conventions (rules) governing the exchange of data between hardware and/or software components in a communication network. A common protocol is TCP/IP which is a protocol which enables all computers to interpret and use data transmitted over the internet.. The first part of the Uniform Resource Locator (URL) indicating the set of rules used to retrieve the specified document.
CSC101 Final Review Sheets The protocol is generally followed by a colon, two forward slashes, www, and then the domain name. 6. Peripheral Devices: Any device attached to a computer in order to expand its functionality. Common peripheral devices include printers, scanners, and microphones. Peripheral devices are devices that are optional compared to hardware that is necessary to operate to the computer (i.e. CPU) Devices such as monitors, printers, and keyboards that connect to the system unit through ports. 7. System Software: Coordinates instructions between hardware and software. System software includes operating systems and utility programs. The operating system is responsible for managing hardware (CPU, storage, peripheral), memory, application programs, and system maintenance. The operating system also provides user interface for the user. Operating systems are divided into four different categories: Real Time (System with a specific purpose and a result) Single User, Single Task (Perform one task at a time, PDA's) Single User, multi-task (Desktop Computer) Multi-User (Allow system access by more than one user, UNIX) System utilities are programs that perform computer housekeeping tasks such as manage system resources, improve efficiency, and provide virus protection. The set of programs that enables computer's hardware devices and application software to work together; it includes the operating system and utility programs. 8. CPU- the central processing unit, the brains of the computer. 9. Volatile- Memory lost when the computer shuts off. Non Volatile- Memory that is not lost when the computer is turned off. 10. Virtual memory-The space on the hard drive that the operating system stores data to if you don't have enough random access memory to hold all of the programs you're currently trying to run. 11. Application Software programs used to complete tasks. Application Software includes productivity software, specialty software, entertainment software, educational & reference software, & personal software. It is the software you install on a computer to run programs such as word processors or games. 12. FAT is the file allocation table. It is an area on a hard disk or floppy disk where information is stored about the location of each piece of every file on the disk and about the location of unusable areas of the disk. 13. Disk Fragmentation When a file is saved to the hard drive, it tries to keep everything in the same location (or cluster) Over the course of time files will be deleted, leaving blank areas between files. If you install another large program, the hard drive tries to fill the holes, thus breaking up the program storage block. 14. Binary System has only 2 digits, 0 & 1, has a base of 2, uses binary digits 15. Desktop Operating System- system software that controls the way in which a computer system functions, including the management of hardware, peripherals, and software.
CSC101 Final Review Sheets 16. Analog has a continuous range of values and digital has a set of discrete values. Digital/Analog Forms of Bandwidth that measures how much data can be sent through a communications channel in a given amount of time Digital- measures in bits/second (bps) Analog- measures in cycles/second (Hertz( Hz)) 17. 8 bits = 1 byte Bits- smallest unit of information (0,1) Bytes- 8 bits= 1 byte= 1 character (a,b,c,#,&) 18. Internet is a massive network of data/information and the world wide web is a way of accessing the data/information from the internet. Internet The Network (LAN) Information travels through the internet Communicates in many protocols ( FTP, Http, SMTP) Email, FTP, IM, Usenet all use Internet NOT Web WWW A way of accessing the information that travels the Internet Uses http to communicate Uses browsers to access documents Hyperlinks connect pages Multimedia