Computer Programming

Software

Two Basic ClassificationsSystem / Application Software

System Software is any computer software

which manages and controls computer hardware – Linux, Microsoft Windows, and Mac OS X are examples.

System software performs tasks like transferring data from memory to disk, or rendering text onto a display device.

Application Software are programs that enable the

end-user to perform specific, productive tasks, such as word processing or image manipulation .

Application software employs the capabilities of a computer directly to complete a task that the user wishes to perform.

One way of demonstrating the relationship between them …

Software Categories

Vertical software•developed for a specific 'type' of client, usually a specialist of some kind (e.g. accountants, doctors, retail outlet) •may be customisable

Custom software•written for a specific client

Horizontal software•designed to be useful for a wide range of users performing varied tasks

Software User Interfaces

Text-based interfaces (CLIs)•Command line: user types in specified commands with fixed syntax (example)•Menu-driven: user chooses from a 'list' of options ('point and shoot') (example)Graphical user interfaces (GUIs)•user works with operating system through the GUI •places special demands on hardware (especially display and memory) •applications are 'tied' to the interface•supports multitasking though use of windows

Operating system developments on microcomputers

Virtual memory •provides more memory without extra (costly) RAM•requires fast secondary storage •essential for multitasking

Print Spooling •form of background processing •example of multitasking •Various forms of cross-platform standardisation