Everything Flashcards
What is a byte?
8 bits.
What is analog data?
A continuous representation, analogous to the actual information it represents.
What digital data?
A discrete representation, breaking the information up into separate elements.
What does it mean to digitise?
To represent something (such as an image or sound) as a structured sequence of binary digits.
What does it mean to discretise?
To convert a continuous space into an equivalent discrete space, often for the purpose of easier calculation.
What is Data compression?
Reduction in the amount of space needed to store a piece of data?
What is the compression ratio and how do you calculate it?
The size of the compressed data is divided by the size of the original data.
compression ratio = size (compressed data) / size (data)
What lossless compresssion?
Once compressed data can be retieved without any loss of original information. For example texts
What is lossy compression?
Once compressed some information may be lost in the process of compression. An example is sound and images
What is Pulse Coded Modulation?
The process of digitising an analogue signal:
sampling: periodically reading the signal value
quantisation: discretise value
What is colour depth?
THe number of bits used to encode colours in the RBG model varies.
What is a pixel?
A dot with a colour in an image, or on a screen.
What is resolution?
The number of pixels in an image.
What are raster graphics?
IMages encoded pixel by pixel.
What are vector graphics?
Images described as a collection of geometricals objects.
What is a video codec?
An encoder/decoder. A software or hardware that compresses and decompresses digital video. The compression is typically lossy.
What is a gate?
A device that performs a basic operation on electrical signals.
What is a circuit?
Gates combined to perform more complicated tasks.
What is a transistor?
A deivce that acts either as a wire that conducts electricity ot as a resistor that blocks the flow of electricity, depending on the voltage level of an input signal.
What is a combinational circuit?
The input values explicitly determine the output.
WHat is a squential circuit?
The output is a function of the input values and the existing state of the circuit.
What is circuit equivalance?
Two circuits that produce the same output for identical input.
What is a half adder?
A circuit that cmoputes the sum of two bits and produces the correct carry bit.
What is a full adder?
A circuit that computes the sum of two bits and a carry-in value and produces the sum and a cary-out value.
What is a multiplexers?
A circuit that uses input control signals to determine which of seveal input data signals is routed to its ouput signal.
What is an S-R latch?
An S0r latch (Set/Reset) stores a single binary bit.
What are stored-programs?
Procans can be represented and stored as data inside a computer. There is no significant difference between instructions and data. Therefore, we can store programs in the main data memeory.
What are the characteristics of theVon Neumann Architecture?
Any stored-program computer where instructions and data cannot be fetched at the same time, as they are communicated on a common bus.
What is the control unit?
THe organising force in the computer. It provides timing sinals and control signals, direction the ALU, memory and I/O devices to responds to instructions. It contains the Instruction Register and the Program Counter.
What is the Instruction Register?
A register containing the instructions that is currently being executed?
What is the program counter?
Register containg the address of the next intruction to be executed.
What does the Arithmetic/Logic Unit (ALU)?
Performs basic arithmetic operations such as addition and multiplication. Also performs logical operations such as AND, OR, and NOT.
What is a bus?
A communcation system that transfers data. Can be between componets inside a computer or between computers.
What is the memory bus?
Connects the CPU, main memory, other internal componets.
What is RAM?
Random Accesss Memory, memory in which each location can be accessed and changed. A form of volatile memory, where data is lost when power is turned off.
What is ROM?
Read Only Memory (ROM), memory in which each location can be accessed but not changed. A form of non-volatile memory.
What is main memory for?
Main memory (RAM) is used for storing data and programs when currently being run.
What is secondary storage?
Devices that store programs and data for extended time. For example: MAgnetic tape drives, MAgnetic disks, optical disks, solid state drives.
What is an embedded system?
Computers that are dedicated to perform a narrow range of functions/specified tasks.
What is parallelism?
The ability to perform operations concurrently.
What is data-level parallelism?
Data subjected to the same operation sequence simultaneously. A single instruction used for multiple data.
What is task-level parallelism?
Entire tasks can be completed simultaneously, either on the same data, or on different data.
What is an array list?
We can store that data in a contigoues block of memory.
What is linked list?
Each data is stored by itself and with a pointer to the next piece of data.
What is linked list?
Each data is stored by itself and with a pointer to the next piece of data.
What is the purpose of transistors?
Creates logic gates that are used in logic circuits.
What is an abstract type?
An abstract data type dfines a data type from the perspective of a user.
