Computing - Software

A set of instructions that perform a task.

Programs that perform a task.

Written to control and make use of the hardware. Overseen by the operating system (O/S).

A way of allowing humans to communicate with the computer and vice versa. Graphical - uses icons in which user clicks on to perform an action. +ves - instinctive to use, no commands needed to learn. -ves - more processing power to display icons, slower than CLIs, good graphical display needed.

Command-Line - require typed inputs from user who must learn a set of commands. +ves - can be used on less advanced machines as less memory is required, run quicker than GUIs. -ves - need to learn commands.

The O/S loads programs and data into the memory and removes them when they are not in use. Ensures that data in use is not overwritten by other data.

The O/S manages these and their drivers -  a small piece of software that tells the computer how to operate the peipheral.  The O/S may need to coordinate peripherals to run at different speeds or ask the user for a driver if the correct one cannot be found.

Running more than one program at the same time. The O/S divides up the processor time between all of the process by working on one for a split second before switching to another one.

The O/S comntains features to keep the data and programs secure. Anti-virus guards against malicious software. Firewalls protect against hackers. User access levels allow different users to do different things to data by giving every user a password, e.g. a pupil password only allows the user to read files whereas an admin password allows the user to modify files.

A small program designed to carry out a limited maintenance task.

The O/S makes sures files are stored in a hierachical structure and provide the user with a means by which to locate files. Storing files hierarchically makes searching for them easier. 

Disk Formatting - permanetly deleting everything on it, including O/S itself. Guarantess that viruses are removed, ensures all personal data is removed if disk is being disposed of, and disk formatting is used when installing a new O/S.

File Transfer - O/S moves files on the disk, within a directory structure and from one device to another, e.g. from the HDD to a USB.

Defragmentation - When a disk has been written and re-written to multiple times, the files are stored across the disk as fragments, increasing disk access time. Defragmentation moves similar file fragments together so disk acess time is faster.

System Information and Diagnosis - provide information to the user and software about the computer itself, such as HDD capacity, processor speed and the name of the O/S. They can solve problems when something is not working, e.g. if the user cannot acess a web page, a diagnosis utility can help to identify the problem.

System Cleanup Tools - are essential to keep a computer operating efficiently. Unecessary files can be deleted and cleanup tools can change system settings that are incorrect or recommend them.

Automatic Updating - ensures that a computer always has the most recent version of a program. Newer versions usually run quicker, have more features and have bugs removed.

Programs which perform real world tasks.

Produced for one specific user or company. +ves - has all the features that you want. -ves - expensive as cost is not spread between multiple users, may take several years to complete, bugs are not spotted as fast

You buy it from a shop or pay to download it. +ves - instantly available (unless you are waiting for it to be released), cheaper than custom written as the cost is spread across lots of people. -ves - may not have all the features you want it to.

Developed by a community of users and the source code it publically available. +ves - it's free, you can adapt it to how you want, generally to a high standard. -ves - you need a high level of programming skill to customise it, no guarantees that it is to a high standard.

The developer owns the source code and licences the complied code for clients to use. +ves - (for developer) you can make money from it, harder for people to copy your code as the source code it not released. (for user) Most likely going to be to a high standard. -ves - Expensive.