Buses and types of computer.
Paul Strickland
Liverpool John Moores University
1
Introduction
• Bus Architecture
• Types of Computers
2
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?
3
Address Bus
• May be 8-, 16-, 32-, ... bits.
• Unsigned binary value gives address in
RAM.
• 32 bits = 2 + 10 + 10 + 10.
• Address 4 * 1024 * 1024 * 1024 bytes = 4
gigabytes.
• What about 8, 16 and 24-bit address
buses?
4
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. 1000.345 - 0.000345 would take you
longer than 3 - 2!
5
Palm top
• up to 64Mb RAM
• No disc (need to connect to another
computer)
• 256MHz processor
6
Personal computers
• Up to 4Gb RAM
• 100+ Gb Hard disk
• 1GHz + processor
7
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.
8
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.
9