Systems and Application Software - INFO1

Software can refer to all kinds of data and programs.

The term 'software' refers to all the actual programs or data that a computer system uses - it's basically all of the stuff stored electronically, (hardware is what you can see.)

There are two types of software:

• Systems software
  This is a set of programs that organise, utilise and control hardware in a computer system. Systems software includes: the operating system, utilities and drivers
• Application software
  This is designed to make use of the computer system for specific purposes.

Applications software can be generic or task-specific.

• Generic software packages are for everyday use and are very common. Things such as word processors, spreadsheet applications etc.
• They can be used for lots of tasks, not just for one specific job. For example, spreadsheets can do things like sort numbers and create charts
• Task-specific software packages have one particular purpose, e.g. payroll software can be used to process wages - you can't write a letter on it.
• Task-specific software is usually for a specialised application, so the user needs training in both software abd subject area, e.g. CAD/CAM

Computer systems are made up of many devices - software drivers let the computer control this hardware. A software driver is designed to control input, storage and output devices. (It's a program.)

• It allows communication between the OS and the HW
• Devices can be configured by the OS to work as intended
• It used to be that whenever a new piece of HW was installed (added to the system), it needed to be installed by the driver before it would work
• 'Plug and play' devices are a lot more common, where drivers are loaded automatically when a new device is added into the computer system

System utilities are programs that perform specific functions.

• Compression
  Converts data into a format that takes up far less space. Useful when data is being sent from one computer to another
• File Conversion
  Each file saved on a computer has an extension, e.g. .doc .xls. These are related to the specific application used to create the file. Utilities software allows applications to open a file with a different extension
• Keeping Configuration Files
  Contains information about a systems parameters - when a program is run, needs to see which conditions it should adapt too

An operating system is essential computer software that controls and monitors all the applications

It provides an interface between the user, software and hardware - the 'heart of the system'

There are two main OS for computers, these are:

• Microsoft Windows
  This is the most popular operating system, it provides a GUI (graphical user interface) for the user. It was originally based on DOS (disk operating system). MS-DOS is still behind the interface in many of the older versions.
• Linux
  Rival operating system to Microsoft, although now is no way near as popular. The fact that the basic system is free to download and open for development has led to its growth

Different types of operating systems are:

• Single user systems - one user has access at a time (PCs)
• Multi-user systems - more than one user, LANs with computer servers
• Distributed systems - uses more than one system to run an application. Common to networks (LANs), one application has to be run at different sites
• Batch processing - data is first collected together in batches before later being inputted into the system, usually when there isn't a great demand from other processes. E.g. banks usually colelct cheques thhat have been paid in throughout the day, batch processing takes place over night

An operating system does various different things.

• Allocates internal memory
  When several applications are running at once there are often great demands on memory. OS handle the allocation of RAM.
• Schedules programs and resources
  Processing has to be prioritised to prevent programs from freezing, and allow the computer to work efficiently
• Monitors the systems input and output devices
  An OS may have to prioritise input and output devices so that they work efficiently - being able to display characters on the screen as they are being typed in from the keyboard while another document is being printed
• Logs errors
  Needs to provide error messages when applications fail
• Checks for unauthorised access
  Different access privilages such as read only, read/write - the operating system controls granting access of privelages

Can an operating system multi-task?

As lots of programs need to be run at once, OS need to be able to multi-task.

Multi-tasking makes it appear as if multiple programs are running at once, but it's generally just an illusion caused by the fast processing speed of the CPU

Multicore processors are becoming more popular - these actually allow the CPU to run tasks and programs simultaneously

Standardisation can affect users hardware and software.

In ICT, there are many different standards - not all compatible

• Hardware needs to be compatible with systems software. If replacing software, need to make sure it works with the old HW
• OS have a set of standards so only certain applications work
• Components may need upgrading so they work with newer SW
• If fewer people use HW and SW (older versions), then sources of technical support will be limited and expensive