Class 9 Computer Science Computer Aptitude Notes

SECTION-I : COMPUTER KNOWLEDGE

ABBREVIATIONS

• AAC : Advanced Audio Coding (audio compression format defined by the MPEG-2 standad)
• ABI : Application Binary Interface
• ABR : Area Border Router
• ABR : Available Bit Rate
• AD : Active Directory
• ADC : Analog - To - Digital Converter
• ADC : Apple Display Connector (DVI variant)
• AH : Active Hub
• AHA : Accelerated Hub Architecture
• Ajax : Asynchronous Java Script and XML
• AL : Active Link
• ALGOL : Algorithmic Language
• ALU : Algorithmic and Logical Unit
• AM : Active Monitor
• AMD : Advanced Micro Devices
• AMR : Audio Modem Riser
• AoE : ATA over Ethernet
• APCI : Application- Layer Protocol Control Information
• API : Application Programming Interface
• APIPA : Automatic Private IP Addressing
• ASCH : American Standard Code for Information Interchange
• ASG : Abstract Semantic Graph
• ASP : Application Service Provider
• AST : Abstract Syntax Tree
• ATA : Advanced Technology Attachment
• ATM : Asynchronous Transfer Mode
• AVC : Advanced Video Interleaved
• AWT : Abstract Windowing Toolkit
• BASIC : Beginner's All-Purpose Symbolic Instruction Code
• BCD : Binary Coded Decimal
• BEEP : Blocks Extensible Exchange Protocol
• BER : Bit Error Rate
• BFD : Binary File Descriptor
• BGP : Border Gateway Protocol
• bin : binary
• BINAC : Binary Automatic Computer
• BIOS : Basic Input Output System
• bit : binary digit
• Blob : Binary large object
• Blog : Web Log
• BMP : Basic Multilingual Plane
• BOOTP : Bootstrap Protocol
• BPEL : Business Process Execution Language
• bps : bits per second
• CAD : Computer- Aided Design
• CAE : Computer- Aided Engineering
• CAI : Computer- Aided Instruction
• CAT : Computer- Aided Translation
• CAQ : Computer- Aided Quality Assurance
• cc : C Compiler
• CD : Compact Disc
• CD-R : CD-Recordable
• CD-ROM : CD Read-only Memory
• CD-RW : CD- Rewritable
• CG : Computer Graphics
• CGA : Colour Graphics Array
• CGI : Common Gateway Interface
• CGI : Common -Generated Imagenry
• CIFS : Common Internet Filesystem
• CLI : Command Line Interface
• CLR : Common Language Runtime
• CNC : Computer Numerical Control
• COBOL : Common Business-Oriented Language
• CPU : Central Processing Unit
• CRT : Cathode Ray Tube
• CSI : Common System Interface
• CT : Computerised Tomography
• CTCP : Client-To-Client Protocol
• CTL : Computational Tree Logic
• CTS : Clear To Send
• CUA : Common User Access
• DAC : Digital-To-Analog Converter
• DAP : Directory Access Protocol
• DB : Database
• DBA : Database Administrator
• DBMS : Database Management System
• DCC : Direct Client-to-Client
• DDR : Double Data Rate
• DES : Data Encryption Standard
• DFD : Data Flow Diagram
• DFS : Distributed File System
• DHTML : Dynamic HTML
• DIVX : Digital Video Express
• DLL : Dynamic Link Library
• DLP : Digital Light Processing
• DMA : Direct Memory Access
• DOS : Disk Operating System
• DPI : Dots Per Inch
• DPMI : DOS Protected Mode Interface
• DSL : Digital subscriber Line
• DSL : Domain- Specific Language
• DSN : Database Source Name (ODBC)
• DTE : Data Terminal Equipment
• DTR : Data Terminal Ready
• DVD : Digital Versatile Disc
• DVD : Digital Video Disc
• DVD-R : DVD- Rewritable
• DVI : Digital Visual Interface
• DVR : Digital Video Recorder
• EAP : Extensible Authentication Protocol
• EBCDIC : Extended Binary Coded Decimal Interchange Code
• EDO : Extended Data Out
• EEPROM : Electronically-Erasable Programmable Read-Only Memory
• EFF : Electronic Frontier Foundation
• EFI : Extensible Firmware Interface
• EGA : Enhanced Graphics Array
• EGP : Exterior Gateway Protocal
• eID : electronic ID card
• EIGRP : Enhanced Interior Gateway Routing Protocol
• ELF : Executable and Linkable Format
• ELM : Electronic Mail
• EOM : End of Message
• EPROM : Erasable Programmable Read-Only Memory
• EUC : Extended Unix Code
• EXE : EXEcutable
• FAP : FORTRAN Assembly Program
• FAT : File Allocation Table
• FAQ : Frequently Asked Questions
• FDC : Floppy Disk Controller
• FDD : Floppy Disk Drive
• FIFO : First In Fist Out
• FHS : Filesystem Hierarchy Standard
• FCS : Frame Check Sequence
• FPU : Floating Point Unit
• FS : File System
• FSB : Front Side Bus
• FTP : File Transfer Protocol
• FXP : File eXchange Protocol
• Gb : Gigabit
• GB : Gigabyte
• GCR : Group Code Recording
• GDI : Graphics Device Interface
• GIF : Graphics Interchange Format
• GIGO : Garbage In, Garbage Out
• GPU : Graphics Processing Unit
• GUI : Graphical User Interface
• HAL : Hardware Abstraction Layer
• HCI : Human Computer Interaction
• HDD : Hard Disk Drive
• HD DVD : High Definition DVD
• HDL : Hardware Description Language
• HHD : Hybrid Hard Drive
• HID : Human Interface Guidelines
• HIG : Human Interface Guidelines
• HPFS : High Performance File System
• HSM : Hierarchical Storage Management
• HTM : Hierarchical Temporal Memory
• HTML : Hypertext Markup Language
• HTTP : Hypertext Transfer Protocol
• HTX : Hyper Transport eXpansion
• HURD : Hird of Unix- Replacing Daemons
• HVD : Holographic Versatile Disc
• IBM : International Business Machines
• ICMP : Internet Control Message Protocol
• ICP : Internet Cache Protocol
• IDL : Interface Definition Language
• IE : Internet Explorer
• IGMP : Internet Group Management Protocol
• IGRP : Interior Gateway Routing Protocol
• IHV : Independent Hardware Vendor
• IIOP : Internet Inter-Orb Protocol
• IIS : Internet Information Services
• IM : Instant Messaging
• IMAP : Internet Message Access Protocol
• I/O : Input/Output
• IP : Internet Protocol
• IPC : Inter-Process Communication
• IPP : Internet Printing Protocol
• Ipsec : Internet Protocol security
• IPTV : Internet Protocol Television
• IPX : Internetwork Packet Exchange
• IRC : Internet Relay Chat
• IRP : I/ORequest Packet
• IRQ : Interrupt Request
• ISC : Internet Storm Center
• ISO : International Organisation for Standardisation
• ISOC : Internet Society
• ISP : Internet Service Provider
• ISR : Interrupt Service Routine
• ISV : Independent Software Vendor
• IT : Information Technology
• ITU : International Telecommunication Union
• J2CE : Java 2 Cryptographic Edition
• JDS : Java Desktop System
• JMX : Java Management Extensions
• JMS : Java Message Service
• JNDI : Java Naming and Directory Interface
• JNI : Java Native Interface
• JPEG : Joint Photographic Experts Group
• JS : Java Script
• JSON : Java Script Object Notation
• JSP : Java Server Pages
• JUG : Java Users Group
• Kb : Kilobit
• KB : Kilobyte
• kHz : Kilohertz
• LAN : Local Area Network
• LIFO : Last In first Out
• LSB : Least Significant Bit
• MAN : Metropolitan Area Network
• MANET : Mobile Ad- Hoc Network
• Mb : Megabit
• MB : Megabyte
• MBCS : Multi Byte Character Set
• MBR : Master Boot Record
• MDI : Multiple Document Interface
• MICR : Magnetic Ink Character Recognition
• MIMO : Multiple-Input Multiple-Output
• MIPS : Million Instructions Per Second
• MIME : Multipurpose Internet Mail Extensions
• MMX : Multi-Media Extensions
• MNG : Multiple-Image Network Graphics
• MPEG : Motion Pictures (Coding) Experts Group
• MPL : Mozilla Public License
• MSB : Most Significant Bit
• MS-DOS : Microsoft DOS
• MVS : Multiple Virtual Storage
• NEXT : Near- End Cross Talk
• NFS : Network File System
• NIO : New I/O
• NMI : Non- Maskable Interrupt
• NNTP : Network News Transfer Protocol
• NOP : No Operation
• NOS : Network Operating System
• NT (Windows) : New Technology
• NTP : Network Time Protocol
• OOP : Object- Oriented Programming
• OPML : Outline Processor Markup Language
• OS : Operating System
• OSS : Open- Source Software
• P2P : Peer-To- Peer
• PAN : Personal Area Network
• PAP : Password Authentication Protocol
• PATA : Parallel ATA
• PC : Personal Computer
• PCI : Peripheral Component Interconnect
• PCLe : PCI Express
• PCL : Printer Command Language
• PGA : Pin Grid Array
• PIC : Peripheral Interface Controller
• PIC : Programmable Interrupt Controller
• PINE : Program for Internet News & Email
• PIO : Programmed Input/ Output
• PnP : Plug-and- Play
• PoE : Power over Ethernet
• PPC : Power PC
• PPI : Pixels Per Inch
• PPP : Point-to-Point Protocol
• PPPoA : PPP over Ethernet
• PPTP : Point- to-Point Tunneling Protocol
• PSU : Power Supply Unit
• QDR : Quad Data Rate
• QFP : Quoted For Permanence
• QoS : Quality of Service
• RADIUS : Remote Authentication Dial In User Service
• RAID : Redundant Array of Independent Disks
• RAM : Random Access Memory
• RARP : Reverse Address Resolution Protocol
• RDBMS : Relational Database Management System
• RDF : Resource Description Framework
• REFAL : REcursive Functions Algorithmic Language
• RIP : Routing Information Protocol
• ROM : Read Only Memory
• ROMB : Read-Out Motherboard
• RTOS : Real Time Operating System
• SaaS : Software as a Service
• SAN : Storage Area Network
• SATA : Serial ATA
• SAX : Simple API for XML
• SBP-2 : Serial Bus Protocol 2
• SBU : Standard Build Unit
• SCSI : Small Computer System Interface
• SDL : Simple Direct Media Layer
• SDN : Service Delivery Network
• SDR : Software-Defined Radio
• SDRAM : Synchronous Dynamic Random Access Memory
• SMBIOS : System Management BIOS
• SMTP : Simple Mail Transfer Protocol
• SP : Service Pack
• SPI : Serial Peripheral Interface
• SQL : Structured Query Language
• SUS : Single UNIX Specification
• SVD : Structured VLSI Design
• TCP : Transmission Control Protocol
• TCP/IP : Transmission Control Protocol/Internet Protocol
• TTA : True Tap-Audio
• TTF : True Type Font
• TTS : Text-to-Speech
• TTY : Teletype
• UAC : User Account Control
• UART : Universal Asynchronous Receiver Transmitter
• UEFI : Unified Extensible Firmware Interface
• UI : User Interface
• UL : Upload
• UPS : Uninterruptible Power Supply
• URI : Uniform Resource Identifier
• URN : Uniform Resource Name
• USB : Universal Serial Bus
• Var : variable
• VB : Visual Basic
• VBA : Visual Basic for Applications
• VBS : Visual Basic script
• VFAT : Virtual FAT
• VFS : Virtual File System
• VGA : Video Graphics Array
• VGCT : Video Graphics Character Table
• VLAN : Virtual Local Area Network
• VM : Virtual Memory
• VOD : Video On Demand
• VoIP : Voice over IP
• VPN : Virtual Private Network
• VT : Video Terminal
• WAFS : Wide Area File Services
• WAIS : Wide Area Information Server
• WAN : Wide Area Network
• WAP : Wireless Application Protocol
• Wi-Fi : Wireless Fidelity
• WiMAX : Worldwide Interoperability for Microwave Access
• WInFS : Windows Future Storage
• WINS : Windows Internet Naming Service
• WLAN : Wireless Local Area Network
• WMA : Windows Media Audio
• WMV : Windows Media Video
• WOL : Wake-on-LAN
• WOM : Wake-on-Modem
• WPA : Wi-Fi Protected Access
• WSDL : Web Services Description Language
• WUSB : Wireless Wide Area Network
• WWID : World Wide Identifier
• WWW : World Wide Web
• XAML : eXtensible Application Markup Language
• XHTML : eXtensible Hypertext Markup Language
• XML : eXtensible Markup Language
• XMMS : X Multimedia System
• XNS : Xerox Network Services
• XSL : eXtensible Stylesheet Language
• XSL-FO : eXtensible Stylesheet Language Formatting Objects
• XSLT : eXtensible Stylesheet Language Transformations
• XUL : XML User Interface Language
• Y2K : Year Two Thousand
• ZIFS : Zero Insertion Force Socket
• ZISC : Zero Instruction Set Computer
• ZMA : Zone Multicast Address

IMPORTANT TERMS

Question. Access Time
Answer: Access time is the time from the start of one storage device to the time when the next access can be started.

Question. Accessory
Answer: An Accessory is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture. Examples are computer printers, image scanners, tape drives, microphones, loudspeakers, webcams, and digital cameras.

Question. Active Cell
Answer: The cell that continues the value being used or modified in a spreadsheet program, and that is highlighted by the cell pointer. Also known as current cell.

Question. Active Window
Answer: The window in Microsoft Windows with which the user may interact.

Question. Accumulator
Answer: The computer register in which the result of an arithmetic or logic operation is formed (related to arithmetic and logic unit).

Question. Algorithm
Answer: A standard method for computing something; essentially, a mathematical recipe.

Question. Analog
Answer: A continuous waveform signal that can be used to represent such things as sound, temperature, and velocity.

Question. Analog Computer
Answer: A computer in which numerical data are represented by measurable physical variables, such as electrical.

Question. Antivirus
Answer: Computer antivirus refers to a software program that can protect your computer from unwanted viruses and remove any, that penetrate your computer's defenses.

Question. Arithmatic Logic unit (ALU)
Answer: An arithmetic-logic unit (ALU) is the part of a computer processor (CPU) that carries out arithmetic and logic operations on the operands in computer instruction words.

Question. Artificial Intelligence
Answer: Artificial intelligence (AI) is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its chances of success.

Question. ASCII (American Standard Code for Information Interchange)
Answer: ASCII a code for information exchange between computers made by different companies; a string of 7 binary digits represents each character; used in most microcomputers.

Question. Assembly Language
Answer: A programming language that is once removed from a computer's machine language. Machine languages consist entirely of numbers and are almost impossible for humans to read and write. Assembly languages have the same structure and set of commands as machine languages, but they enable a programmer to use names instead of numbers.

Question. Auxilliary Memory
Answer: A high-speed memory bank used in mainframes and supercomputers. It is not directly addressable by the CPU; rather, it functions like a disk. Data are transferred from auxiliary memory to main memory over a high-bandwidth channel.

Question. Backup
Answer: A backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event.

Question. Band Width
Answer: In computer networking and computer science, bandwidth, network bandwidth, data bandwidth or digital bandwidth is a bit rate measure of available or consumed data communication resources expressed in bits/second or multiples of it (kilobits/s, megabits/s etc.).

Question. BIOS
Answer: Basic Input Output System. This is the basic set of instructions that tell the computer how to act. Most computers have these instructions built into a chip that plugs into the motherboard.

Question. Bar Code
Answer: A bar code (often seen as a single word, barcode) is the small image of lines (bars) and spaces that is affixed to retail store items, identification cards, and postal mail to identify a particular product number, person, or location.

Question. Binary
Answer: Computers are based on the binary numbering system, which consists of just two unique numbers, 0 and 1.

Question. Biometric Device
Answer: Biometrics (or biometric authentication) consists of methods for uniquely recognizing humans based upon one or more intrinsic physical or behavioral traits.

Question. Bitmap
Answer: In computer graphics, a bitmap or pixmap is a type of memory organization or image file format used to store digital images.

Question. Blue tooth
Answer: Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short wavelength radio transmissions in the ISM band from 2400-2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security.

Question. Booting
Answer: To boot (as a verb; also "to boot up") a computer is to load an operating system into the computer's main memory or random access memory (RAM).

Question. Browse
Answer: In database systems, browse means to view data. Many database systems support a special browse mode , in which you can flip through fields and records quickly. Usually, you cannot modify data while you are in browse mode.

Question. Bug
Answer: A software bug is the common term used to describe an error, flaw, mistake, failure, or fault in a computer program or system that produces an incorrect or unexpected result, or causes it to behave in unintended ways.

Question. Byte
Answer: Byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits.

Question. CD ROM (Compact Disk- Read Only Memory)
Answer: a type of optical disk capable of storing large amounts of data -- up to 1GB, although the most common size is 650MB (megabytes).

Question. CD-R/W (Compact Disk-Recordable)
Answer: a type of CD disk that enables you to write onto it in multiple sessions. One of the problems with CD-R disks is that you can only write to them once.

Question. Central Processing Unit (CPU)
Answer: The CPU is the computer's control center. Think of it as the brain that does all the thinking (computation), thus it is called the Central Processing Unit. The actual CPU is about 1.5 inches square, yet it is the most critical part of the computer. Having a fast CPU (measured in MegaHertz) greatly aids in the overall speed of your computer.

Question. CMOS
Answer: Acronym " Complimentary Metal Oxide Semiconductor" A CMOS computer circuit consumes very little power and is used in computers to keep track of the system setup information, data, time, type of disk and hard drives, etc, that a computer has in stalled.

Question. Compressed File
Answer: Computer files that have been reduced in size by a compression program. Such programs are available for all computer systems.