lossy/lossless data compression Flashcards
(26 cards)
what does compression do
•reduces the number of bits in a file
•makes the storage capacity of the file lower
•makes data transfer of the file quicker
why is compression good
more data can be stored on a storage device, and transferred in a smaller amount of time.
what happens in lossy compression?
(3 things)
•some of the data is lost and can’t be recovered
•greatly reduces file size
•reduces quality of image/sound
what is lossy compression suitable for?
images, sound and video
what can lossy compression not be used for
text and executable files
what happens in lossless compression
•no data is lost, it’s just encoded differently
•can be turned back into original formal
what is lossless compression used for
all types of data
which is more effective lossy or lossless
lossy
what is lossless compression most useful for
documents and executable files
what does the CPU consist of
ALU, CU, cache, clock, bus
what does the arithmetic logic unit do
performs calculations and logical decisions
what does the control unit do
sends signals to control how data moves around the CPU
what does the cache do
provides fast access to frequently used instructions and data
what does the clock do
the electronic unit that synchronises related components by generating pulses at a constant rate
what is a bus and what does it do
collection of wires through which data needs to be written to or read from
what does the adress bus do
unidirectional- carries the addresses which data needs to be written to or read from
what does the data bus do
bidirectional- carries the actual data or instructions
what does the control bus do
bidirectional- carries command and control signals telling components when they should be receiving reads or writes etc.
what are registers
tiny, super fast pieces of onboard memory inside the CPU each with a very specific function
what do program counters do
hold the address of the next instruction to be executed
what does the MAR (memory address register) do
holds the address in memory which data or an instruction needs to be read from or written to.
what does the MDR (memory data register) do
holds either data or instruction which has been fetched from memory or is about to be written back from memory
what is the accumulator
a set of general purposes registers
what happens in the fetch of the FDE
-fetches the next instructions from main memory (RAM)
-brings instruction back into the CPU
