SOFTWARE & APPLICATION GEN

DISK DEFRAGMENT: move file chunks close together remove unneeded spacing ANTIVIRUS: detects and removes viruses Compression like zipping etc File managers like win explorer Backup utilities, backs up files

Software that manages computer It manages programs, hardware, scheduling of code execution and context switching

multi tasking Multi user Distributed Embedded Real time

Works on multiple PCs

OS for machine with dedicated job eg ATM, printer etc

Designed to carry out actions with guaranteed amount of time

Core of OS, does memory management and processor scheduling

When uses the HDD to store chunks of (pages) of RAM

When OS keeps switching ram from hdd and main

Round robin First come first served Shortest remaining time Multi level queue

Each job is given a fixed amount, if it goes over it gets added to back of queue

Split into queues of different queues

When OS runs a high priority job ISR is an interrupts service routine which runs, like a fiber registers and stack is saved of current job

Source code is freely available (1) … for others to example or recompile (1)

Interpreter goes through each line and converts to machine code and runs Compiler compiles all code to machine code

Lexical Syntax Code gen Optimising

Comments removed, white space removed Creates symbol table and everything is tokenised

Check syntax and produces the abstract syntax tree

Used within company by people who haven’t developed it

Users outside company test it

The user(s) test against the spec

Waterfall Rapid app dev Spiral agile Extreme

Analysis Design CODING TESTING MAINTENANCE

It’s simple and easy to see if it’s running on schedule It carries risks, only at testing can the user see the current progress