Data Representation Flashcards
What are the 4 different uses of the hexadecimal system?
Error codes = These numbers refer to the memory location of the error and are usually automatically generated by the computer.
MAC address = number which uniquely identifies a device on a network
IP address = Each device that is connected to the internet is given this address. IPv6 is a 128-bit number broken down into 16-bit chunks.
HTML color codes = are used when writing and developing web pages. A programming language.
overflow error?
When a calculation produces a result that exceeds the maximum value that can be stored in a given data type.
Logical binary shift - what does it do to the value when numbers are shifted towards the left or right?
Right - dividing by 2
left - multiplying by 2
(if shifting 3 times, then 2 to the power of 3)
Whats the ASCII code system?
set up in 1963 for the use of communication systems and computer systems. Consists of 7-bit codes that represent the numbers, letters, and characters. The extended ASCII code consists 8-bit.
How does a computer store recording?
Sound is analogue, so computers use an ADC to convert analogue to digital data. Sound waves are sampled at regular time intervals.
sampling resolution?
the number of bits used to represent sound amplitude in digital sound recording (also known as bit depth)
Colour depth?
the number of bits used to represent the colours of a pixel.
sampling rate?
the number of sound samples taken per second in digital sound recording
image resolution?
the number of pixels in the X-Y direction of an image, e.g. 4096 x 3192 pixels.
Name the memory size in order, and how many bytes are their in each?
1KB = 1 000 bytes
1 MG = 1 000 000 bytes
1 GB = 1 000 000 000 bytes
1TB = 1 000 000 000 000 bytes
1PB = 1 000 000 000 000 000 bytes
1 EB = 1 000 000 000 000 000 000 bytes
Why do we use data compression?
- to save storage space on devices such as the hard disk/solid state drive
- to reduce the time taken to stream a music or video file
- to reduce the time taken to upload
Lossy file compression?
a file compression method that allows the original file cannot be recovered during the decompression process. e.g. JPEG, mp3
Lossless file compression?
a file compression method that allows the original file to be fully restored during the decompression process. e.g. run-length encoding (RLE)
MP3?
lossy file compression method used for music files
MP4?
Lossy file compression method used for multimedia files
JPEG?
a form of lossy file compression used with image files that rely on the inability of the human eye to distinguish certain colour changes and hues
Run-length coding (RLE)?
lossless file compression technique used to reduce the size of text and photo files in particular.
represent runs of identical data values as a single value and a count
