AS Computer Science

• Binary magnitudes; binary prefixes (kibi, mebi, gibi, tebi) and decimal prefixes (kilo, mega, giga, tera)
• Number systems: binary, denary, hexadecimal and Binary Coded Decimal (BCD)
• One's complement and two's complement representation
• Conversion of an integer between number bases and representations
• Binary addition and subtraction using positive and negative integers
• How overflow can occur
• Practical applications of BCD and hexadecimal
• Character sets: ASCII, extended ASCII and Unicode

• ○ Binary, denary and hexadecimal 30 min · 5 questions
• 1.1-2 Coming soon
• 1.1-3 Coming soon

• Bitmap images: pixel, file header, image resolution, colour depth
• Estimating the file size of a bitmap image
• Effects of changing the resolution and the colour depth
• Vector graphics: drawing object, property, drawing list
• Justifying the use of a bitmap image or a vector graphic
• Representation of sound: sampling, sampling rate, sampling resolution

Coming soon

• The need for compression
• Lossy and lossless compression
• Compressing a text file, a bitmap image and a sound file; run-length encoding

Coming soon

• The need for input, output, primary and secondary storage
• Embedded systems, and their benefits and drawbacks
• Principal operations of a range of hardware devices
• The use of buffers
• RAM and ROM; SRAM and DRAM; PROM, EPROM and EEPROM
• Sensors, and monitoring and control systems

Coming soon

• Symbols and functions of the NOT, AND, OR, NAND, NOR and XOR gates
• Truth tables for each gate
• Construction of logic circuits, truth tables and logic expressions

Coming soon

• Networks, including the internet: LAN, WAN, client–server and peer-to-peer
• Hardware a network needs, and the media that carry it
• The internet, IP addressing and the domain name service

Coming soon