Chapter 1 Data Representation Flashcards
What is the Denary Number System?
A number system based on 10 thus uses 10 unique values from 0 to 9.
What is the Binary Number System?
A number system based on 2, thus only has the values 0 or 1.
What is the Hexadecimal Number System?
A number System Based on the number 16 thus having numbers 0 to 9 and letters A to F.
What is a bit?
A basic unit of information for computers. The word bit comes from the words “Binary Digit”. Binary means Two . 1 or 0 are the only values
What is a byte?
8 bits or 2 nibbles
Each keyboard character is stored as…
A byte
(Example, A=01000001)
What does each letter of the hexadecimal number system represent in denary?
A= 10
B= 11
C= 12
D=13
E=14
F=15
Uses of the hexadecimal number system
MAC Addresses
Color codes for HTML
IPv6 addresses
Assembly code
Memory Dumps
Error codes
MAC Address
Media-Access Control Address is a 48-bit unique number that identifies the device connected to the internet.
(NN-NN-NN-DD-DD-DD)
The first half is the identity number of the manufacturer
The second is the serial number of the device.
HTML
Hyper-Test Markup Language- is a markup language that is used design, write and develop webpages.
What is a Markup Language?
A markup language is a language use in the processing, definition and presentation of text ( for example, specifying the color of the text)
IP address
An Internet protocol address which gives a unique address for a device connected to the internet.
Difference between IPv4 and IPv6
IPv4 is a 32-bit number written in either denary or hexadecimal
IPv6 is a 128-bit number broken into 16-bit chinks written in hexadecimal.
Overflow Error
The result of carrying out a calculation that results in a value that is too large for the computer’s allocated word size (8-bit, 16-bit, 32-bit, and so on).
Two’s complement
A method of representing negative numbers in binary, when applied to the 8-bit system; the leftmost bit (most significant bit) is given the value -128.
What is meant by Logical shift?
An operation that shifts bits to the left or the right on a register. Any bits that are shifted to the left or right are replaced with zeroes.
Character Set
A list of characters that have been defined by the computer Hardware and software. The character set is necessary so that the computer can understand human characters
ASCII code
A character set for all the characters on a standard keyboard and control codes.
Unicode
A character set that represents all the languages of the world (The first 128 characters are the same as the ASCII code)
Sampling Resolution
The number of bits used to represent sound amplitude in a digital sound recording.
Bit depth
The number of bits used to represent the smallest unit in a sound file.
Sampling rate
Is the number of samples taken per seconds
Bitmap images
An Image made up of pixels.
Color depth
The number of bits used to represent the colors of a pixel.
Pixel
Derived from the word “picture element”, This is the smallest element used to make up an image on a display.
Image resolution
The number of pixels in the X-Y direction of an image. (Example 4096x3192)
Pixelated (image)
This is the result of zooming into a bitmap image, on zooming out the pixel density becomes so diminished to such a degree that the actual pixels themselves can be seen.
Pixel density
The number of pixels per square inch
Compression
The reduction of the size of a file by removing repeated and redundant pieces of data.
Bandwidth
The maximum rate of transfer of data across the internet. Measured in kilobits per second (kbps) or megabit per second (Mbps)
Lossy (file compression)
A file compression method in which parts of the original files cannot be recovered during the decompression process, for example, JPEG, mp3
Lossless (file compression)
A file compression method that allows the original file to be fully restored during the decompression process, for example, Run- Length Encoding (RLE).
Audio compression
A method of reducing the size of a sound file by using perceptual music shaping.
MP3
A lossy file compression method for music files
MP4
A lossy file compression method for multimedia files
JPEG
From Joint Photographic Expert Group: A form of lossy file compression used with image files that rely on the inability of the human eye to distinguish between certain color changes and hues.
Run length Encoding (RLE)
A lossless file compression technique used to reduce the size of text and photo files in particular.
