Definition
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Term
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Computer Architecture
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Consists of hardware and software components and follows Input, Process, Output, Storage model
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Computer system
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The "brain" of the computer, processes data to information according to instructions
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Central Processing Unit (CPU)
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Controls retrieval of instructions from primary memory as well as sequence of execution
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Control Unit (CU)
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Performs all basic arithmetic, logical, I/O operations
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Arithmetic Logic Unit (ALU)
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Small location that can hold data
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Register
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Holds address of where processed data will need to be stored
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Memory Address Register (MAR)
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Holds data that will be taken to address that the above is holding.
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Memory Data Register (MDR)
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Directly accessible by CPU, holds both data and instructions that are running on computer system.
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Primary memory
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One type of above. Stores executing program instructions and data in unique memory locations that each have address and content. Stored data can be overwritten. Volatile (if power is lost, so are unsaved changes).
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Random Access Memory (RAM)
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Other type of two rows above. Like above but holds and data cannot be overwritten (even if power is lost) used to boot computer
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Read-Only Memory (ROM)
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Preferred for main RAM of computer system
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Dynamic RAM (DRAM)
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Faster but more expensive than above
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Static RAM (SRAM)
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Divided into L1 and L2, small amount of above that holds most commonly used and accessed information from RAM, making computer system faster. Located closer to CPU than RAM
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Cache
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Cache located on processor itself
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L1 cache
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Cache placed between primary memory and processor
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L2 cache
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Four stages of machine instruction cycle
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Fetch (from primary memory to CU)
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Decode (in CU)
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Execute (by CPU)
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Store results in primary memory
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May be written to like RAM but non-volatile at the same time. Relatively slow, but high data capacity. Examples of devices: Hard drive, USB, Floppy disc
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Secondary memory
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Operating and Application Systems
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Controls computer's hardware resources and provides services for computer programs. Examples: Windows, Mac, Linux
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Operating System (OS)
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Responsibility for communicating directly with peripheral devices such as keyboard, monitor, mouse
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Peripheral communication
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Ensuring that one application does not interfere with memory used by other applications so that the latter does not stop functioning or have its data overwritten.
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Memory management
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Efficient allocation of resources so that application can run as effectively as possible on computer
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Resource monitoring
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Managing connections to and interactions with networks of other computer systems to allow sharing of resources
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Networking
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Keeping track of files stored in memory and discs, as well as files in use by applications
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Disc access
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Username/password, magnetic cards, biometric, etc.
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Security
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Keep trace of activity of any user in computer system
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Log file
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Installed by manufacturer, aims to complete tasks.
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Software application
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Produces documents. Includes composition, editing, formatting, and sometimes printing. Example: Microsoft Word
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Word processor
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Organizes and analyzes data in rows and columns. Also performs mathematical calculations, financial and statistical operations, and graph creation. Example: Microsoft Excel
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Spreadsheet
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Organized collection of data and information in the form of rows/records and columns/fields.
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Database
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Manages, creates, modifies, and extracts information from above. Example: Microsoft Access
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Database management system (DBMS)
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Can access, retrieve, and present content (including web pages, images, videos, etc.) on World Wide Web. Example: Chrome
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Web browser
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Allows exchange of digital messages between author and recipient(s), regardless of whether either is active.
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Email
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Commonly used by engineers and designers, allows creation and modification of a design, which can be viewed from any angle and can convey information on materials and dimensions. Example: Fusion 360
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Computer Aided Design (CAD)
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User can edit digital images with tools such as moving, cropping, scaling, and erasing. Example: Photoshop
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Graphic processing software
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Allows user to interact with applications in numerous ways.
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Graphical User Interface (GUI)
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Commands are typed into it. Example: CMD, Terminal
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Command line interface (CLI)
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Where buttons, icons, menus, and other I/O elements are placed
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Toolbar
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Displays list of commands to be chosen by user to perform various functions
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Menu
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Communicates information to user, allowing them to respond by choosing an option from specific choices. Example: "Do you want to save changes to …?"
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Dialogue box
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Binary Representation
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Basic unit of information in computer systems, carries only either 1 or 0. Eight of these make one Byte.
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Bit
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Uses ten digits (0-9) to represent any number regardless of size
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Decimal number system
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Uses two digits (0, 1) to represent numbers. Most widely used number system in CS. Examples: 1=1, 10=2, 100=4, …
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Binary number system
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Where positive numbers start with 0 and negative numbers start with 1
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Two's complement
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Uses 16 digits (0-F), A=10, B=11, …, F=15
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Hexadecimal number system
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Whole number
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Integer
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Character-encoding scheme based on English alphabet. Such characters have values from 0-127, inclusive
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ASCII
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Character-encoding scheme like above but with more symbols and non-English characters
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Unicode
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Sequence of characters
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String
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Represented with RGB values. Example: 3366CC
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Colour
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Simple Logic Gates
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Real electrical circuit simulating boolean operators
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Logic gate
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Both inputs must be true/on
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AND
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One or both inputs may be true/on
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OR
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Inverse of input
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NOT
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Inverse of operation #1
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NAND
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Inverse of operation #2
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NOR
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One input may be true/on but not both
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XOR
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Represents input and output of complex logical/boolean statements
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Truth table
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