Chap 1 Vocab - Information Representation and Multimedia - AICE Computer Science AS

vocab words for chapter 1 in the Hodder Education textbook :] (reworded a bit so they make more sense)

Binary

base two number system that only uses the values 0 and 1

Bit

abbreviation for “binary digit”, either a 0 or a 1.

One’s Complement

each binary digit in a number is reversed (0 to 1 and 1 to 0). This lets us represent both negative and positive numbers.

Two’s complement

take a number in One’s Complement and add 1 to the rightmost spot. This lets us represent negative and positive numbers, as well as letting us do math operations with them easily.

Sign and magnitude

take a normal binary number and add a bit to the leftmost spot to indicate sign of the number (0 for + and 1 for —)

Hexadecimal

base-16 number system. It uses the denary digits 0 to 9 and the letters A to F.
Counting looks like 0 1 2 3 4 5 6 7 8 9 A B C D E F
Lets us represent a byte in two digits! (each hexadecimal digit holds the same amount of information as 4 binary digits)

Memory dump

outputs (prints or displays) the contents of the computer’s memory so the user can read it

Binary-coded decimal (BCD)

number system that uses 4bits to represent each denary digit

Used when denary numbers MUST be used for precision, like in banking.

ASCII code

simpler coding system for all the characters on an English keyboard, only represents 128 characters!
Used by older computers, or when more characters aren’t needed

Character set

a list of characters that have been defined by computer hardware and software. It is necessary to have a method of coding, so that the computer can understand human characters.

Unicode

coding system which represents all the languages of the world, not just English! Includes diacritics, emoji, and more! (that won’t be on the test, it’s just cool)

The first 128 characters are the same as ASCII code, for compatibility reasons.

Bit-map image

store an image as colored pixels

Pixel

the smallest picture element that makes up an image.

(the little squares you see on a computer screen, or in an image)

Colour depth

number of bits used to represent the colours in a pixel, e.g. 8 bit colour depth can represent 2⁸ = 256 colours.