Data

Unfinished. These only include Year 10 content, sorry.

Binary

Base 2, e.g. 1001 1101

Denary

Base 10, e.g. 24

Hexadecimal

Base 16, e.g. 5F (one digit per nibble), used for MAC addresses and colours

Bits and bytes

one binary digit, 8 binary digits (bits)

1000 storage units

KB (kilobyte), MB (megabyte), GB (gigabyte), TB (terabyte)

1024 storage units

KiB (kibibyte), MiB (mebibyte), GiB (gibibyte), TiB (tebibyte)

Binary arithmetic

Operations fundamental to all computer calculations

ASCII

American Standard for Information Interchange - 7 bit character set

A is at 65, a is at 97 - 32 between upper and lower case

Solutions to ASCII limitations

Extended ASCII (8 bit ASCII), unicode

Logical left shift

Unsigned integers

Move MSB left, move other digits, fill space with 0s

Can lead to overflow

Arithmetic left shift

Signed integers

Same as logical left shift

Can lead to sign-flipping

Logical right shift

Unsigned integers

Move LSB right, move other digits, fill space with 0s

Can lead to loss of precision

Arithmetic right shift

Signed integers

Move LSB right, move other digits but MSB is maintained, fill space with MSB

Can lead to loss of precision

Overflow responses

• Crash and report overflow error

• Truncate the number

• Wrap the number back around to 0

Two’s complement

Used for signed integers - MSB is a negative number

Conversion: starting from the right, copy out every number up to and including the first 1, flip every number after that