Unit 1: Data Representation

1.1 Number systems

1 Understand how and why computers use binary to represent all forms of data

2(a) Understand the denary, binary and hexadecimal number systems
(b) Convert between
(i) positive denary and positive binary
(ii) positive denary and positive hexadecimal
(iii) positive hexadecimal and positive binary

3 Understand how and why hexadecimal is used as a beneficial method of data representation

4(a) Add two positive 8-bit binary integers
(b) Understand the concept of overflow and why it occurs in binary addition

5 Perform a logical binary shift on a positive 8-bit binary integer and understand the effect this has on the positive binary integer

6 Use two’s complement to represent positive and negative 8-bit binary integers

1.2 Text, sound and images

1 Understand how and why a computer represents text and the use of character sets, including American standard code for information interchange (ASCII) and Unicode

2 Understand how and why a computer represents sound, including the effects of the sample rate and sample resolution

3 Understand how and why a computer represents an image, including the effects of the resolution and colour depth

1.3 Data storage and compression

1 Understand how data storage is measured

2 Calculate the file size of an image file and a sound file, using information given

3 Understand the purpose of and need for data compression

4 Understand how files are compressed using lossy and lossless compression methods