1 Buses and types of computer. Paul Strickland Liverpool John Moores University

2 Introduction Bus Architecture Types of Computers

3 Data Bus May be 8-, 16-, 32-,... bits. Carrying 1, 2, 4,... bytes of data at one time. How many bytes could a 24-bit data bus carry? What sort of data bus could carry 8 bytes at once?

4 Address Bus May be 8-, 16-, 32-,... bits. Unsigned binary value gives address in RAM. 32 bits = Address 4 * 1024 * 1024 * 1024 bytes = 4 gigabytes. What about 8, 16 and 24-bit address buses?

5 Speed Most computers measure clock speed in MHz or GHz. These really mean 1 million or 1 billion instructions per second. Super computers use FLOPS; Floating Point Oerations Per Second. e.g would take you longer than 3 - 2!

6 Palm top up to 64Mb RAM No disc (need to connect to another computer) 256MHz processor

7 Personal computers Up to 4Gb RAM 100+ Gb Hard disk 1GHz + processor

8 High Performance Systems Several processors in parallel, with Gb of RAM on each. several Tb (1024 Gb) of storage available. Up to 1000 G-FLOPS (=Peta flops) speed.

9 Homework Find an example of each of the 3 types. How? –do a web search on “High Performance Systems” –go in a computer shop. –visit an online computer dealer e.g. Amazon –read a computer magazine. Find out the amount of RAM, disk size and clock speed for each.