Week 2 - Data Representation Flashcards
What is data?
Data is any type of information stored within computer’s memory that can be represented as a binary number or a stream of binary numbers.
What is a word?
A word is a basic unit of data that the CPU processes at a time. The size is determined by the system (on a 32-bit system, a word is 4 bytes, 8 bytes on 64-bit)
How does a computer know how to interpret a binary number/stream?
The computer doesn’t inherently know just by looking at it. However, given the context (via the data type, instruction, encoding, etc) it can determine what it will be used for.
Why hexadecimal?
Hexadecimal numbers are easier to comprehend and can be written in shorter form than binary. The are used for things such as memory addresses, colour formats (#RRGGBB), MAC addresses, etc.
Why octal?
Octal is used as often but it has less digits as it can be made up of 3 bits to represent a digit. They are used when the number of bits in a word is multiple of three. A usage of octal is for representing file permissions on UNIX systems.
What is ASCII?
ASCII is the American Standard Code for Information Interchange. It is character encoding.
Give a brief overview of bitmap images.
Bitmap images is an array of unsigned numbers where each element specifies the colour at that location. For example black = 0 and white = 255. Between is a greyscale.
How is audio digitized?
Conversion of analogue to digital involves taking samples of the value of the sound wave and then converting the value of each sample into an unsigned number.
