Binary units are used to measure digital data storage. The smallest unit is a bit which can have a value of 1 or 0. 8 bits make up a byte. 1024 bytes make up a kilobyte. Common units include kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes and zettabytes with each unit being 1024 times larger than the previous. Converting between units involves multiplication when going to smaller units and division when going to larger units.

2. Binary Units The smallest unit of data which can be represented on a computer system is a binary digit or bit . A bit can have either the value 1 or 0 . 1 1 1 1 0 0 0 0

3. Binary Units Bits are often represented in groups of 8, known as a byte . 10110101 A collection of 1024 bytes is known as a kilobyte . Investigate why there are 1024 bytes in a kilobyte instead of 1000.

4. Binary Units What comes next? Can you complete the following table? Unit Value Storage bit 1 or 0 byte 8 bits Character Kilobyte Megabyte Gigabyte Terabyte Petabyte Exabyte Zettabyte

5. Binary Units What comes next? Can you complete the following table? Unit Value Storage bit 1 or 0 byte 8 bits Character Kilobyte 1024 bytes Half page of text Megabyte 1024 kilobytes Two minute MP3 file Gigabyte 1024 Megabytes One hour movie (approx) Terabyte 1024 Gigabytes 128 DVD movies Petabyte 1024 Terabytes 7 billion Facebook photos Exabyte 1024 Petabytes 50,000 years of DVD video Zettabyte 1024 Exabytes 180 million x Library of Congress

6. Converting Binary Units In measurement, we wouldn’t say 13500 cm, we would say 135 metres. The same applies to computing units. Converting from a smaller unit to a larger unit requires division e.g. 120 bits = 120 / 8 = 15 bytes 13345 bytes = 13345 / 1024 = 13.03 kilobytes 1561235 bytes = 1561235 / 1024 = 1524.64 kilobytes = 1524.64 / 1024 = 1.489 Megabytes

7. Converting Binary Units Converting from a larger unit to a smaller unit requires multiplication e.g. 3 Terabytes = 3 x 1024 = 3072 Gigabytes 0.15 Megabytes = 0.15 x 1024 = 153.6 kilobytes 0.000366 Kilobytes = 0.000366 x 1024 = 0.375 bytes = 0.375 x 8 = 3 bits