50 terms

IB Computer Science - Topic 2 - Computer Organization

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machine instruction cycle
The process by which a computer

1) retrieves program instructions (fetch) from memory
2) determines what actions the instruction requires (decode)
-- if necessary pulls data from memory
3) performs the instruction (execute)
-- if necessary stores results in memory
CPU (Central Processing Unit)
Component of a computer responsible for gathering data and instructions, interpreting and executing instructions, and sending data/results to storage.
ALU (Arithmetic Logic Unit)
Responsible for computing mathematic and boolean operations. A component of the CPU
CU (Control Unit)
Part of the CPU that implements the microprocessor instruction set; it extracts instructions from memory and decodes and executes them, and sends the necessary signals to the ALU to perform the operation needed.
register
A small, very fast, temporary, memory storage location.
memory address register
A register on the CPU that either stores the memory address from which data will be fetched to the CPU or the address to which memory will be sent and stored.
memory data register
A register on the CPU that contains the data read from or to be stored in main memory.
Program Counter
A Register of the CPU that stores the address of the next instruction that needs to be executed
Instruction Register
A register of the CPU that stores the contents of the current instruction to be executed
Aggregator
A register of the CPU that stores the output of the ALU
primary memory
The primary memory of a computer is made up of the Read-Only Memory (ROM) and the Random Access Memory (RAM), CPU registers and Cache Memory. These are the memory or storage locations directly accessible to the processor and are the fastest types of memory.
secondary memory
This is a non-volatile/persistent storage device used to store the operating system, applications and data in a computer system so that they are available the next time the system is started.
Volatile Memory
Form of memory that require a constant source of power to retain their state. eg: RAM, Cache
Non-Volatile Meomory
Form of memory that persists when a device is powered down. eg: Magnetic Storage, Flash, ROM, DVD
RAM (Random Access Memory)
Often referred to as Main Memory or simply Memory its the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor.
ROM (Read-Only Memory)
"Built-In" computer memory containing data that normally can only be read, not written to. It is accessed at start up and stores the Basic Input Output System (BIOS) or other low-level operating systems
cache memory
Memory storage built on or very close to the CPU to allow super fast read/write access.
bus
A connection between two or more components of a computer system used for transporting binary information.
data bus
A parallel bundle of metal traces used to electrically transfer data to and from the CPU and Main Memory.
address bus
A parallel bundle of metal traces used to electrically transfer the memory location to be read from/written to.
operating system
A collection of programs used to allow a computer system to be used.
Operating System Responsibility: memory management
The process of controlling and coordinating computer memory, assigning portions called blocks to various running programs to optimize overall system performance.
Operating System Responsibility: Peripheral Communication
Managing connections and data transfer to connected devices like mice, keyboards, and monitors
Operating System Responsibility: Storage Management
Protect files from unauthorised reading and writing. Defragment file systems
Operating System Responsibility: Networking
Open connections to networks, eg: wifi, ethernet, 4G
Operating System Responsibility: Multitasking
allowing a user to perform more than one task at a time.
Operating System Responsibility: Security
Separate individual user's data, programs, and settings and restrict access to unauthorized users.
word processor
a computer program that provides special capabilities beyond that of a text editor such as the WordPad program that comes as part of Microsoft Windows operating systems.
Spreadsheet
a computer application that simulates a physical spreadsheet by capturing, displaying, and manipulating data arranged in rows and columns
database management system
a program that lets one or more computer users create and access data in a database
email
software which allows users to send and recieve electronic messages, attach files and forward on to others.
browser
an application program that provides a way to look at and interact with all the information on the World Wide Web
CAD (Computer-Aided Design)
software used by architects, engineers, drafters, artists, and others to create precision drawings or technical illustrations.
graphic processing software
software that allows the creation and manipulation of digital graphics e.g. photograph editing and manipulation
GUI (Graphical User Interface)
A way for users to interact with software by interpreting visual elements like toolbars, buttons, and other controls.
Bit (binary digit)
the smallest unit of data in a computer (0 or 1).
Byte
a unit of data that is eight binary digits (bits) long; can represent a letter, number, or typographic symbol.
Binary
a base 2 numbering scheme in which there are only two possible values for each digit: 0 and 1.
denary/decimal
the base-10 number system, probably the most commonly used number system. (numbers 0-9)
hexadecimal
a base-16 number system consisting of the symbols 0 through F.
RGB
A way to digitally represent colours using binary numbers to represent varying levels of red (R), green (G) and blue (B) light. The more bits used for each, the more colours can be represented but taking up more storage.
Boolean operator
simple words (AND, OR, NOT, or AND NOT) used as conjunctions to combine or exclude keywords in a search, resulting in more focused and productive results
AND
the output is true when both inputs are true; otherwise the output is false.
OR
the output is true if either or both of the inputs are true; if both inputs are false then the output is false.
XOR
the output is true if either, but not both, of the inputs are true; the output is false if both inputs are false or if both inputs are true.
NOT
reverses the logic state.
NAND
operates as an AND gate followed by a NOT gate; the output is false if both inputs are true; otherwise the output is true.
NOR
operates as an OR gate followed by a NOT gate; output is true if both inputs are false; otherwise the output is false.
truth tables
a breakdown of a logic function by listing all possible values the function can attain.
logic gates
a building block of a digital circuit constructed with transistors