Chapter 2: Computers Flashcards
A computer consist of (4 components)
- Central processing Unit (CPU)
- Input/Output Units (I/O)
- Main (Primary) memory (storage)
- Auxiliary (secondary) storage
Central Processing Unit (CPU)
- Brain of the computer
- Processes data
- Executes programs stored in main memory by fetching instructions, examining them, and executing them
- Contains the logic of the machine
- Consists of the arithmetic logic unit (ALU), control unit, and two registers (Instruction and program counter)
Logic
- Ability of a computer to follow instructions
- Stored in Central Processing Unit (CPU)
Central Processing Unit (CPU) consists of (3 things)
- Control unit
- Arithmetic Logic Unit
- Registers (2 of them: instruction and program counter)
Control unit of a Central Processing Unit (CPU)
- Fetches program instructions (e.g. PRINT, INPUT) from main memory and determines their type and supervises their execution.
- Tells the computer what to do
- Ex: Such as instructing the computer which device to read or send output to
Arithmetic/Logic Unit (ALU) of a Central Processing Unit (CPU)
Performs operations: (+,-,*,/) and comparisons (,=) needed to carry out the instructions
Registers In a Central Processing Unit (CPU)
- Small very high-speed storage used to store temporary results and certain control information
- Instruction and Program counter registers
Instruction Register
Holds the instruction which is currently being executed
Program Counter (Instruction Location Counter) (Address Register)
Points to the instruction which will be executed next
Computer Program (Also called source code)
- Step-by-step directions for performing a specific task (instructions)
- Written in a language the computer can understand
- Also called a source code
- Source code must be translated into object code, consisting of binary 0s and 1s
Other things computer have
- Hardware: Physical devices such as keyboards, monitors, and processing units
- Software: Programs written in computer languages
- Single or multiprocessors (multiprocessing: use of 2+ CPU’s in a computer system)
Bus
Link (wire) between devices connected to the computer
Disk Drive
Peripheral device (device that connects to the computer) for recording, storing, and retrieving information
CPU case (computer chassis/tower)
- Enclosure containing the computer’s main components
- Also called computer chassis or tower
Motherboard
Main circuit board containing connectors for attaching additional boards
3 basic operations of a computer
- Arithmetic operations
- Logical operations
- Storage and retrieval operations. Data is stored in bits
Main/core/primary Memory
- Stores data and information, application programs, and operating systems and other system software
- Volatile (Contents are lost when electrical power is turned off)
Secondary Memory
- Nonvolatile (contents are not lost when computer is turned off)
- Holds data when the computer is off or during course of a program’s operation
- Serves as archival storage