Informatics Practices · Ch 1 — Computer System
System Software
System Software
Some software exists not to serve any one task of the user, but to keep the computer itself running. The software that provides the basic functionality to operate a computer, by interacting directly with its constituent hardware, is called system software. It knows how to operate and use the different hardware components of a computer, and it provides its services either directly to the end user or to some other software. The three main examples are operating systems, system utilities and device drivers.
(A) Operating System
The operating system is, as its name implies, the system software that operates the computer. It is the most basic system software of all — without it, no other software can work. Beyond simply running the machine, the operating system:
- manages the other application programs running on the computer, and
- provides access and security to the users of the system.
Popular operating systems include Windows, Linux, Macintosh, Ubuntu, Fedora, Android and iOS — the last two being the systems that run most phones and tablets.
(B) System Utilities
Software used for the maintenance and configuration of the computer system is called a system utility. Utilities come in two groups:
- Shipped with the operating system — tools that arrive pre-installed as part of the OS, such as the disk defragmentation tool, the formatting utility and the system restore utility.
- Installed separately to improve performance — utilities not bundled with the operating system but needed to keep the system healthy and fast, such as anti-virus software, disk cleaner tools and disk compression software.
Either way, a utility's job is upkeep: it maintains, repairs, cleans or configures the system rather than producing work for the end user.
(C) Device Drivers
The purpose of a device driver is to ensure the proper functioning of one particular device. The reasoning behind drivers is worth understanding. The operating system handles the overall working of the computer system — but new devices and components are being added to computers every day, and each device has its own diverse characteristics. It is simply not possible for the operating system alone to manage every existing and newly invented peripheral. …
The figure is a layered box diagram that stacks the entire software world of a computer between two ends: the User at the top and the Hardware at the bottom. Downward arrows connect the layers in order. From the user, an arrow leads to a box labelled User Interface. Below that comes a row containing two boxes side by side — Application software and Programming tools — showing that these two categories sit at the same level, both serving the user from on top of the system layers. Beneath them, a dashed box encloses the next run of layers: System Utilities, then the Operating System, then the Device Drivers, with the final arrow arriving at Hardware at the very bottom.
Two vertical brackets annotate the stack from the sides. On the right, one bracket runs along the dashed group and labels it System Software — making the point that utilities, the operating system and device drivers together form the system-software category — while a second label, Free and Open Source Software (FOSS), runs along the outer edge. On the left, a vertical bracket labels the licensing bullets Proprietary Software / Freeware. These side annotations teach that licensing categories cut across the functional layers: any of this software may be proprietary, freeware or FOSS depending on the terms under which it is released. …