chapter 3 - hardware Flashcards
random access memory (RAM)
random access memory (RAM) is a volatile memory that clears when powered off and stores running programs, OS, and data currently being used
dynamic RAM (DRAM)
constructed from capacitors which require regular recharging that store one bit per capacitor and are used in main memory
static RAM (SRAM)
constructed from flip-flops which continue to store data indefinitely while a computer is switched on. used for cache memory as it has more than one transistor per bit and faster access speeds
read-only memory (ROM)
read-only memory (ROM) is a non-volatile memory that can not be written to but can be read from multiple times. used to store BIOS, start-up instructions, boot program, or kernel of the operating system
programmable ROM (PROM)
type of ROM that can be programmed once
erasable programmable ROM (EPROM)
type of ROM that can be programmed more than once using UV light
electronically erasable programmable ROM (EEPROM)
type of ROM thar can be modified by the user, which can be written and erased repeatedly using pulsed voltages
liquid crystal display (LCD)
a liquid crystal display (LCD) is a screen back-lit by LEDs with liquid crystal cells sandwiched between polarises
organic light emitting diode (OLED) screens
use organic films of flexible semi-conductors between 2 charged electrodes that emit light when a voltage is applied
resistive touch screens
use a flexible polyester upper surface causing contact between electrically resistive layers when touched
capacitive touch screens
have a rigid surface above a conductive layer which undergoes a change in electrical state when touched
general system
fast systems that can install new software and are used for multiple things at once
embedded system
a microprocessor-based computer system with a software designed to perform a particular functions, either independently or as part of a larger system
sensor
a hardware device that measures a property and transmits a value to a computer/microprocessor
actuator
a hardware device that receives a signal from a computer and adjusts the setting of a controlling device for movement and action
