Questions

IDLE is useful for programmers because it does stuff like colouring bits of code depending on what it does to help you know if you have written it write so you can identify errors, also it tries to tell you errors when you write it.

Open source software is where the software is available for everyone.

Pros for using it include the fact that it is widely used and therefore tested and most bugs would be fixed, it is specifically modified to fit the purpose.

Cons for using it include possible low quality and no guarantee of support if it goes wrong.

Editors are where you write code, and it can do stuff such as colour bits of code depending on what it does, this make it easier for the person to write code in it.

Disk defragmenters sort out the memory, getting rid of gaps to make it more efficient and gain space, it is needed because when you delete and add files, slight gaps appear.

Firewalls exist to detect viruses and stop them and to stop us accidently going on dangerous websites.

They also stop information being stolen from you.

Off-the-shelf software is software written and sold by companies for a variety of tasks.

it is very cheap because the code is being sold to lots of people.

Software

3 main categories of software are:

Systems software  -  operating systems, device drivers, firmware, servers, utilities, interfaces

Development software  

Applications

Operating system ~ platform, a collecting if programs that control the hardware.

At the heart of the operating system is the kernel, the kernel looks after low level hardware operations.

       Running: what CPU is currently doing

       Runnable: waiting to run after what is running

       Waiting: waiting to join the queue 

GUI: graphical user interface

It uses icons (pictures) to represent resources and actions.

Main examples are Windows, MacOS, UNIX, LINUX

Device drivers tell your CPU to finish what it is doing as soon as possible and deal with peripheral devices.

Utility software deal with simple maintenance tasks

Disk defragmenters gets rid of gaps caused by deleting and adding files to improve access speeds.

Interpreters and compilers: both translate high level code into machine code (source code to object code) but interpreters do it 1 line at a time and execute it. 

Assemblers translate assembly languages (1 line is 1 machine instruction like LMC) into machine code.

Linkers link sub programs together. #look up examples

Off the shelf software

    Advantages-immediately available, well tested, cheap

    Disadvantages-may not meet exact requirements

Custom Written software

    Advantages-specifically written

    Disadvantages-expensive and takes time

Open source software

    Advantages-specifically modified, bugs fixed quickly

    Disadvantages-nobody owns it so no guaranteed support, issues with quality