Chapter 3: Hardware Flashcards
Define CPU
Central processing unit
responsible for the execution or processing of all the instructions and data in a computer
Define Von Neumann Architecture
a type of computer architecture which introduced the concept of the stored program in the 1940s
Define ALU
the component of the CPU that carries out all arithmetic and logical operations
Define ACC [Accumulatr]
temporary general-purpose register that stores numerical values at any part of a given operation
Define MAR (memory address register)
a register that stores the address of the memory location currently being read from or written to
Define CIR [current instruction register ]
a register that stores the current instruction being decoded and executed
Define MDR [memory data register]
a register that stores data that has just been read from memory or data that is about to be written to memory
Define PC [Program couunter]
a register that stores the address where the next instruction to be read can be found
Define control unit
the component of a computer’s CPU that ensures synchronisation of data flow and programs throughout the computer by sending out control signals along the control bus
Define system clock
produces timing signals on the control bus to ensure synchronisation takes place
Define clock cycle
s temporary memory using static RAM to hold frequently used data/instructions by the CPU thereby increasing CPU performance. More generally, cache means any area of storage used to quickly access frequently-used data - other examples include web cache, database cache, DNS cache
Define register
a temporary component in the CPU which can be general or specific in its use; it holds data or instructions as part of the Fetch–Decode–Execute cycle
Define address
a label for a memory location used by the CPU to track data
Define memory location
a numbered place in memory where values can be stored
Define system bus
a connection between major components in a computer that can carry data, addresses or control signals
Define address bus
the system bus that carries the addresses throughout the computer system
Define data bus
the system bus that allows data to be carried from CPU to memory (and vice versa) or to and from input/ output devices
Define control bus
– the system bus that carries signals from control unit to all other computer components
Define unidirectional
can travel in one direction only
Define bidirectional
can travel in both directions;
Define over clocking
changing the clock speed of a system clock to a value higher than the factory/recommended setting
Define core
a unit on a CPU made up of an ALU, control unit and registers
Define dual core
A CPU containing 2 cores
Define Fetch-Execute-Decode
– a cycle in which instructions and data are fetched from memory, decoded and finally executed
Define BIOS
– a suite of programs on firmware that are used to perform the initialisation of a computer system during the boot-up process
Define opcode
– part of a machine code instruction that identifies what action the CPU has to perform
Define operand
part of a machine code instruction that identifies what data is to be used
Define instruction set
the complete set of machine code instructions used a particular microprocessor
Define embedded system
a combination of hardware and software designed to carry out a specific set of functions
Define barcode
a series of dark and light lines of varying thickness used to represent data; the code has to be scanned using laser or LED light source
Define keyfield
the field that uniquely identifies a record in a file
Define QR code
a matrix of dark and light squares which represent data
Define frame QR code
a type of QR code that includes a space for advertising
Define DAC
device that converts digital data into electric currents that can drive motors, actuators and relays
Define ADC
a device that converts analogue data (for example, data read from sensors) into a form understood by a computer
Define CCD
a light sensitive cell made up of millions of tiny sensors acting as photodiodes
Define virtual keyboard
an onscreen keyboard which uses the features of the touch screen to emulate a physical keyboard
Define touch screen
a screen that allows the user to select or manipulate a screen image using the touch of a finger or stylus; touch screens most frequently use capacitive, infra- red or resistive technology
Define RSI (repetitive strain injury)
pain felt in the muscles, nerves and tendons caused by a repetitive action (for example, excessive clicking of a mouse button over a period of time)
Define optical mouse
a pointing device that uses a red LED to track the movement of the device and then relays its coordinates to a computer
Define pointing device
an input device that allows the user to control the movement of an onscreen cursor or to allow onscreen selection by clicking a button on the device
Define CMOS
a chip that generates an electric current (or pulses) when light falls on its surface
Define DSP
a processor that calculates, for example, the coordinates of a pointing device based on the pulses of electricity received
Define optical character recognition
technology that can convert hard copy text or images into a digital format to be stored in a computer memory
Define CAD
software used to create drawings
Define CT scanner
technology that can create a 3D image of a solid object by slicing up the object into thin layers (tomography)
Define capacitive touch screen
a type of touch screen that uses the change in the screen’s capacitance (the ability to store an electrical charge) when it is touched by a finger or stylus
Define infra-red touch screen
a type of touch screen that uses infra-red beams and sensors to detect where the screen has been touched
Define resistive touch screen
a type of touch screen that uses two conductive layers which make contact where the screen has been touched
Define actuator
an output device that converts electrical energy into mechanical movement
Define DMD
a chip that uses millions of tiny mirrors on its surface to create a video display
Define thermal bubble
inkjet printer technology whereby tiny resistors create heat and form an ink bubble which is ejected onto paper in an inkjet printer
Define piezoelectric crystal
a crystal located in an ink reservoir within an inkjet printer; the crystal vibrates and forces ink out onto paper
Define direct 3D printing
a 3D printing technique in which the print head moves in the x, y and z directions
