Software

Hardware is the physical part of a computer that can be seen and touched (RAM, keyboard, printer, monitor, CPU). Software is the set of instructions and data that makes hardware work; it cannot be touched. Hardware is useless on its own; software is the interface between people and hardware. A document or image stored on a disk is a softcopy; once printed, a hardcopy.

Software falls into three categories: system software, programming tools and application software.

System software gives the basic functions by working directly with the hardware:

• Operating system (OS): the most basic system software, without which other software cannot run. It manages programs and provides access and security to users. Examples: Windows, Linux, macOS, Ubuntu, Fedora, Android, iOS.
• System utilities: for maintaining and configuring the computer. Some come with the OS (disk defragmenter, formatting, system restore); others are added to improve performance (anti-virus, disk cleaner, disk compression).
• Device drivers: each handles the working of one particular device. A driver is the interface between the device and the operating system, hiding the hardware details, like a language translator.
• A computer can work without application software, but not without system software.

Application software works on top of system software for users' particular needs:

• General purpose: ready-made for a wide audience: LibreOffice Calc, Adobe Photoshop, GIMP, the Mozilla browser, iTunes.
• Customised: tailor-made for one organisation or person: websites, school management software, accounting software. Like buying cloth and having it stitched to measure.

Licences:

• Free and Open Source Software (FOSS): free to use, with the source code open for anyone to improve: Ubuntu, Python, LibreOffice, OpenOffice, Mozilla Firefox.
• Freeware: free to use, but the source code may not be available: Skype, Adobe Reader.
• Proprietary software: must be bought from the vendor who holds the copyright: Microsoft Windows, Tally, Quick Heal.

Example (new): a hospital's patient-records system written just for that hospital is customised application software; the printer driver on its computers is system software; and the free spreadsheet program its staff use, with code anyone can read, is FOSS.