the history of drivers

Driver, in computer science, a software program that expands the capabilities of a computer to control various input and output devices. A device is any machine component attached to a computer such as CD-ROM players, disk drives, keyboards, mice, modems, monitors and printers.

Devices may be considered either peripheral or integral. A device is peripheral if the computer can function without it. A printer, for example, is a peripheral device because it is not essential to the operation of the computer. Monitors and keyboards, however, are essential to the function of a computer and are therefore considered integral devices.

Many driver programs come as part of a computer’s operating system—the software that schedules tasks, allocates data storage, and coordinates data transmission between the computer, connected devices, and other computers. When connecting peripheral devices, the computer user often must load a new driver into the computer for each device. All devices require a driver program to function. Each model of a particular device usually comes with its own driver software. For example, each printer model, from each manufacturer, comes with its own driver software to be installed with the PC’s operating system software.

In a computer, the driver serves as a translator between devices and the programs that send commands to the devices. For example, when a user selects the print command in a word-processing program, the program sends a generic command to the printer via the operating system. The driver intercepts this command and translates it, converting it into a specialized command that the printer can understand. The driver program then accesses the hardware registers of the device. Registers are storage areas within the device’s central processing unit (CPU). The number of registers and the size (number of bits) of each help determine the performance and speed of the device.

Many drivers have an interrupt handler that notifies users if a device’s functioning is interrupted. The driver software may then supply the user with information on the status of the device or commands sent to the device and offer error or procedural messages.

In DOS operating systems, driver files have extensions indicated by .sys. In Windows operating systems, drivers have extensions that read .drv. In Macintosh systems, the drivers are signified simply by the name of the device they control, such as “Laser Writer,” and are system extensions.

Device Driver, in computer science, a software component that permits a computer system to communicate with a device. A printer driver is a device driver that translates computer data into a form understood by the intended printer. In most cases, the driver also manipulates the hardware in order to transmit the data to the device. However, device drivers associated with application packages typically perform only the data translation; these higher-level drivers then rely on lower-level drivers to actually send the data to the device.