Machines and Computational Models

input- flow of data into the process from outside the system

process- includes all tasks required to effect a transformation of the inputs

output- data and information flow out of the process

storage- holds the data when turned off

Sequential Algorithms:

• an algorithm that is executed in a sequence (one step at a time)
• most computer algorithms are sequential. 

Parallel Algorithms:

• can be done a step at a time on different proccessing devices and then combined to get result
• many parallel algorithms are executed concurrently
• non-parallel algorithsm are called sequential algorithms

Multi-agents:

• don't have to be on different machines (could be in same chip)
• act without centraliused control 
• do seperate jobs and then come together to compare results 
• often used in artificial intelligence

A whole system virtual machines provides a complete system platform that supports running and execution of a complete operating system. 

The VM software must emulate the entire hardware environment and convert guest system operations to the equivalent OS calls

Advantage- user can have multiple virtual machines operating on the same computer (run independently)

Disadvantage- less efficient than a real machine as it access the hardware indirectly

A Virtual Machine

• any virtual machine is a combination of real machine and virtualising software 
• called a guest
•  further abstraction from the hardware (less performance that real machine because of the abstraction.)

A Process Virtual Machine is...

• designed to support a single process and 1 program 
• also known as an application virtual machines