Language processor software reads a program written in a particular language and processes it to finally convert it into an executable binary program on the computer.
Such programs are called compilers or interpreters. They are also called translators, as they translate a high level language written in English or other language to machine level binary code in 0s and 1s.
For example, a program written in C or Java language is read, understood, the syntax and grammar is checked. Then the semantics or actions to be performed are written in binary machine (CPU) level code.
Utility software :
Software tools that are built for controlling and maintaining a computer or a peripheral accessory device are called utility softwares. These softwares are not directly useful as the application to the end user. They help users or administrators in checking, formatting, correcting mistakes, changing parameters, backing up data or programs etc.
These softwares are designed to analyze, trouble shoot, maintain, optimize performance, rectify, customize, tune parameters on a computer. The utility softwares could also do the same tasks for a big application software too.
A utility to optimize the speed of a computer or to reduce fragmentation of data on a disk are examples.
A device driver software is the system software that interfaces and controls a hardware device that is connected to the (CPU of the) computer.
A device like DVD drive, flash pen drive, printer, monitor, hard disk is connected to the CPU of the computer through hardware connections. To enable the CPU, operating system, and the applications on the computer to communicate to the devices, these device driver softwares are written. A device driver is specific to each type of device. Device drivers are supplied along with the device when purchased. Or, generally an operating system consists of a wide variety of device drivers.
Without a device driver present in the OS, the device cannot be used by the computer. Generally the manufacturer of the devices develops device drivers. When we start a computer, there are various messages displayed on the screen. Some ofthese messages come from the device drivers.