Paul's passion for technology and digital media goes back over 30 years. Born in the UK, he now lives in the US. Show  What is a peripheral device? Here are 10 examples. Canva What Is a Peripheral Device?A peripheral device, also sometimes called an auxiliary device, is any connected device (internal or external) that provides a computer with additional functionality. Peripheral devices fall into three main categories:
10 Examples of Peripheral Devices
I go into more detail regarding each example below. 1. MouseA mouse is an input device that allows you to use point-and-click technology to interact with a computer. Modern mice usually have two buttons with a scroll wheel between them. This device was named a "mouse" because the inventors thought that the wire that connects the device to the computer resembled a mouse tail. Nowadays, mice often connect to the computer using wireless technology. 2. KeyboardKeyboards are the most common input device. The user enters letters, numbers, and other symbols to give the computer information and instruction. Using a keyboard to enter a lot of information is called typing. The keyboard works through push buttons or mechanical switches known as keys which, when pressed, send a signal to the computer. In the past, keyboards used to connect to the computer via a DIN connector, but nowadays they are more likely to connect via a USB port or be wireless. 3. WebcamThese input devices are video cameras that connect to a computer. They can be external or built-in. Webcams are most often used to enable people to see each other when communicating over the internet, or for recording video blogs, or making other videos. As well as computers, webcams can also be built into mobile phones. The first webcam was developed in 1991 at the University of Cambridge. It was pointed at a coffee pot so that researchers from around the Computer Science Department could see if it was full before they got up from their desks. 4. MicrophoneMicrophones are audio input devices. The microphone feeds a sound signal to the computer, where it can be recorded, or streamed across the internet. Microphones are often built into laptops, webcams and mobile phones nowadays. The earliest microphones were telephone transmitters invented in the latter half of the 19th century. Various designs were tried, but the first to have reasonable sound quality were (loose-contact) carbon microphones that were developed independently by David Edward Hughes in England, and Emile Berliner and Thomas Edison in the US. 5. MonitorThe most common output device, monitors enable users to interact with a computer more easily. The monitor essentially displays a signal sent by the computer in a visual format. Monitors look similar to televisions in outward appearance, but typically have a higher display resolution than televisions, enabling greater visual detail, plus they lack a tuner to change channels. As with televisions, modern computer monitors use flat screen technology and have fallen in price in recent years. 6. SpeakersA computer speaker is another common type of output device. They typically come in pairs to provide stereo sound and sometimes with a subwoofer unit too in order to enhance bass frequency. Computer speakers usually have built-in amplifiers and therefore require a power supply, either from the mains, batteries, or via a USB port. In the past, speakers normally received their audio signal via a 3.5 mm jack plug, but it's increasingly common nowadays for computer speakers to be wireless and use Bluetooth technology. Altec Lansing claim to have produced the first commercially available computer speakers in 1990. 7. ProjectorProjectors are optical output devices that enable a roomful of people to see visuals generated by a single computer. As their name suggests, projectors "project" still or moving images onto a screen, blank wall, or other surface. Digital projectors first came onto the market in the early 2000's and have now almost completely replaced older, pre-digital models. They are typically used for presentations, watching movies, or as a teaching aid, and usually connect to the computer via the HDMI port. 8. PrinterPrinters are another common form of output device. They are used to generate hard copies of electronic data stored on a computer, most often text or images onto paper. The first electronic printer to be invented was the EP-101, released by the Japanese company Epson in 1968. Inkjet and laser printers are two of the most common types of printer found today, with modern printers connecting to the computer via the USB port or WI-FI. The rise of other technologies such as email and data storage devices have somewhat diminished the importance of printers in recent years. 9. USB Flash DriveAlso called a thumb drive, gig stick, flash stick, pen drive, USB stick, jump drive, flash-drive, memory stick, or USB memory, the USB flash drive is a data storage device that consists of flash memory with an integrated USB interface. Small and light, USB storage drives are usually removable and rewritable. Since their appearance in the year 2000, these storage devices have gradually increased their storage capacity, while falling in price. They are commonly used for transporting and transferring information and are durable, thanks to a lack of moving parts. 10. External Hard DriveExternal hard drives are input/output storage devices that usually connect to a computer via USB. They hold relatively large amounts of data and plug and play drive functionality enables them to be easily used with a variety of different computers. There are two categories of external hard drives: portable and desktop. Portable external drives are more compact, usually powered by USB and designed for transportation, whereas the desktop version is usually larger and needs external power bricks for power. This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional. © 2019 Paul Goodman Ahmed on March 04, 2020: Thank u man :) Stephen Daniel on February 18, 2020: Awesome!!!! anetu Mohammed on January 19, 2020: This helped a lot Kofi on November 27, 2019: I was staying in USA. In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton.[1] A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details about the hardware being used. A driver communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.[2] PurposeThe main purpose of device drivers is to provide abstraction by acting as a translator between a hardware device and the applications or operating systems that use it.[1] Programmers can write higher-level application code independently of whatever specific hardware the end-user is using. For example, a high-level application for interacting with a serial port may simply have two functions for "send data" and "receive data". At a lower level, a device driver implementing these functions would communicate to the particular serial port controller installed on a user's computer. The commands needed to control a 16550 UART are much different from the commands needed to control an FTDI serial port converter, but each hardware-specific device driver abstracts these details into the same (or similar) software interface. DevelopmentWriting a device driver requires an in-depth understanding of how the hardware and the software works for a given platform function. Because drivers require low-level access to hardware functions in order to operate, drivers typically operate in a highly privileged environment and can cause system operational issues if something goes wrong. In contrast, most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Even drivers executing in user mode can crash a system if the device is erroneously programmed. These factors make it more difficult and dangerous to diagnose problems.[3] The task of writing drivers thus usually falls to software engineers or computer engineers who work for hardware-development companies. This is because they have better information than most outsiders about the design of their hardware. Moreover, it was traditionally considered in the hardware manufacturer's interest to guarantee that their clients can use their hardware in an optimum way. Typically, the Logical Device Driver (LDD) is written by the operating system vendor, while the Physical Device Driver (PDD) is implemented by the device vendor. However, in recent years, non-vendors have written numerous device drivers for proprietary devices, mainly for use with free and open source operating systems. In such cases, it is important that the hardware manufacturer provide information on how the device communicates. Although this information can instead be learned by reverse engineering, this is much more difficult with hardware than it is with software. Microsoft has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called Windows Driver Frameworks (WDF). This includes User-Mode Driver Framework (UMDF) that encourages development of certain types of drivers—primarily those that implement a message-based protocol for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The Kernel-Mode Driver Framework (KMDF) model continues to allow development of kernel-mode device drivers, but attempts to provide standard implementations of functions that are known to cause problems, including cancellation of I/O operations, power management, and plug and play device support. Apple has an open-source framework for developing drivers on macOS, called I/O Kit. In Linux environments, programmers can build device drivers as parts of the kernel, separately as loadable modules, or as user-mode drivers (for certain types of devices where kernel interfaces exist, such as for USB devices). Makedev includes a list of the devices in Linux, including ttyS (terminal), lp (parallel port), hd (disk), loop, and sound (these include mixer, sequencer, dsp, and audio).[4] Microsoft Windows .sys files and Linux .ko files can contain loadable device drivers. The advantage of loadable device drivers is that they can be loaded only when necessary and then unloaded, thus saving kernel memory. Kernel mode vs. user modeDevice drivers, particularly on modern[update] Microsoft Windows platforms, can run in kernel-mode (Ring 0 on x86 CPUs) or in user-mode (Ring 3 on x86 CPUs).[5] The primary benefit of running a driver in user mode is improved stability, since a poorly written user-mode device driver cannot crash the system by overwriting kernel memory.[6] On the other hand, user/kernel-mode transitions usually impose a considerable performance overhead, thus making kernel-mode drivers preferred for low-latency networking. Kernel space can be accessed by user module only through the use of system calls. End user programs like the UNIX shell or other GUI-based applications are part of user space. These applications interact with hardware through kernel supported functions. ApplicationsBecause of the diversity of modern[update] hardware and operating systems, drivers operate in many different environments.[7] Drivers may interface with:
Common levels of abstraction for device drivers include:
So choosing and installing the correct device drivers for given hardware is often a key component of computer system configuration.[9] Virtual device driversVirtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in virtualization environments, for example when a DOS program is run on a Microsoft Windows computer or when a guest operating system is run on, for example, a Xen host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulates a piece of hardware, so that the guest operating system and its drivers running inside a virtual machine can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system as e.g., function calls. The virtual device driver can also send simulated processor-level events like interrupts into the virtual machine. Virtual devices may also operate in a non-virtualized environment. For example, a virtual network adapter is used with a virtual private network, while a virtual disk device is used with iSCSI. A good example for virtual device drivers can be Daemon Tools. There are several variants of virtual device drivers, such as VxDs, VLMs, and VDDs. Open source drivers
Solaris descriptions of commonly used device drivers:
APIs
IdentifiersA device on the PCI bus or USB is identified by two IDs which consist of 4 hexadecimal numbers each. The vendor ID identifies the vendor of the device. The device ID identifies a specific device from that manufacturer/vendor. A PCI device has often an ID pair for the main chip of the device, and also a subsystem ID pair which identifies the vendor, which may be different from the chip manufacturer. See also
References
External links
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