Units of Storage (Bits, bytes, Unicode, ASCII, UTF-8)

What is a bit?

Single binary digit, 1 or 0

How many bits in a byte?

8 bits

How many bytes in a kilobyte?

1024 bytes. Enough to store an email (text only)

How many kilobytes in a megabyte?

1024 kilobytes. Enough to store a one minute song

How many megabytes in a gigabyte?

1024 megabytes. Enough to store 200 photos

How many gigabytes in a terabyte?

1024 gigabytes.

How many terabytes in a petabyte?

1024 terabytes.

What does ASCII stand for

American Standard Code for Information Interchange

Unicode (definition)

An international standard for encoding characters in binary

Characters (definition)

A printable symbol which may be phonetic, numeric, pictorial or represent punctuation

ASCII (history and features)

ASCII originally used 7 bits, 8 bit machines were developed and more characters were added (extended ASCII character set)

ASCII character numbers (7 bit and 8 bit)

7 bit- 127 characters, 8 bit- 256 characters

Problem with ASCII

Doesn’t work with some languages due to large amount of characters

Unicode (History + features)

16 bit computers developed. Unicode uses 32 bits (2 sets of 16 bits). Used to accommodate other languages. Original 127 ASCII characters still have same code values

UTF-8 (history + features)

Invented in 1992. Use any character from Unicode using 1,2,3,4 bytes. When reading, see how many 1 bits it has at the start of the binary code and decides how many bytes it’ll need

Why is the binary number system is used in computing? (2)

Requires low storage. Two states decreases chance of errors occurring when data is being saved or sent

Advantage of ASCII (2)

Requires less storage than other systems. Allows for the exchange of text information between computers.