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Engineering LibreTexts

09-A.1: Supported Linux Devices

  • Page ID
    38101
  • EXAM OBJECTIVES COVERED
    2.7 Explain the use and operation of Linux devices.

    Objectives of this Module

    In this lesson, you will:

    • Identify the different types of devices that support the Linux OS.
    • Learn to configure devices.
    • Understand how to monitor devices.
    • Troubleshoot various issues having to do with hardware devices.

    Reminder: Device Drivers

    Instead of putting code to manage the hardware controllers in the system into every application, the code is kept in the Linux kernel. The software that handles or manages a hardware controller is known as a device driver. The Linux kernel device drivers are, essentially, a shared library of privileged, memory resident, low level hardware handling routines. It is Linux's device drivers that handle the peculiarities of the devices they are managing.

    One of the basic features is that it abstracts the handling of devices. All hardware devices look like regular files; they can be opened, closed, read and written using the same, standard, system calls that are used to manipulate files. Every device in the system is represented by a device special file; for example the first IDE disk in the system is represented by /dev/hda. For block (disk) and character devices, these device special files are created by the mknod command and they describe the device using major and minor device numbers. Network devices are also represented by device special files but they are created by Linux as it finds and initializes the network controllers in the system. All devices controlled by the same device driver have a common major device number. Device drivers are necessary, otherwise it would be impossible to use a device, or at least, to use it efficiently.

    What is a Thin Client?

    In computer networking, a thin client is a simple (low-performance) computer that has been optimized for establishing a remote connection with a server-based computing environment. The server does most of the work, which can include launching software programs, performing calculations, and storing data. This contrasts with a fat client or a conventional personal computer; the former is also intended for working in a client–server model but has significant local processing power, while the latter aims to perform its function mostly locally.[citation needed]

    Thin clients occur as components of a broader computing infrastructure, where many clients share their computations with a server or server farm. The server-side infrastructure uses cloud computing software such as application virtualization, hosted shared desktop (HSD) or desktop virtualization (VDI). This combination forms what is known as a cloud-based system, where desktop resources are centralized at one or more data centers. The benefits of centralization are hardware resource optimization, reduced software maintenance, and improved security.

    • Example of hardware resource optimization: Cabling, bussing and I/O can be minimized while idle memory and processing power can be applied to user sessions that most need it.
    • Example of reduced software maintenance: Software patching and operating system (OS) migrations can be applied, tested and activated for all users in one instance to accelerate roll-out and improve administrative efficiency.
    • Example of improved security: Software assets are centralized and easily fire-walled, monitored and protected. Sensitive data is uncompromised in cases of desktop loss or theft.

    Thin client hardware generally supports common peripherals, such as keyboards, mice, monitors, jacks for sound peripherals, and open ports for USB devices (e.g., printer, flash drive, webcam). Some thin clients include (legacy) serial or parallel ports to support older devices, such as receipt printers, scales or time clocks. Thin client software typically consists of a graphical user interface (GUI), cloud access agents, a local web browser, terminal emulators (in some cases), and a basic set of local utilities.

    Devices: USB

    Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, including several different connectors, of which USB-C is the most recent.

    Released in 1996, the USB standard is currently maintained by the USB Implementers Forum (USB-IF). There have been four generations of USB specifications: USB 1.x, USB 2.0, USB 3.x and USB4.

    USB was designed to standardize the connection of peripherals to personal computers, both to communicate with and to supply electric power. It has largely replaced interfaces such as serial ports and parallel ports, and has become commonplace on a wide range of devices. Examples of peripherals that are connected via USB include computer keyboards and mice, video cameras, printers, portable media players, disk drives and network adapters.

    USB connectors have been increasingly replacing other types as charging cables of portable devices. Pretty much every peripheral device uses the USB connectors now.

    Devices: Wireless

    LPWAN provides long-range communication on small, inexpensive batteries that last for years. This technology supports large-scale IoT networks sprawling over vast industrial and commercial campuses. LPWANs can connect a variety of sensors which facilitates numerous applications from remote monitoring, smart metering and worker safety to building controls and facility management. Nevertheless, LPWANs can only send small blocks of data at a low rate, and therefore are better suited for use in cases that don’t require high bandwidth and are not time-sensitive.

    Cellular technology is well established in the world. It offers reliable broadband communication supporting a variety of applications. On the downside, they impose very high operational costs and power requirements.

    Zigbee is a short-range, low-power, wireless standard (IEEE 802.15.4), commonly deployed in mesh topology to extend coverage by relaying sensor data over multiple sensor nodes. Because of their physical short-range (< 100m), Zigbee and similar mesh protocols are best-suited for medium-range applications with an even distribution of nodes in close proximity.

    Bluetooth and Bluetooth Low Energy (BLE) are wireless technologies used to transfer data over short distances. The technology is frequently used in small consider devices that connect to users' phones and tablets. For instance, the technology is used in many speaker systems. Bluetooth Low Energy uses less power than standard Bluetooth and is used in hardware such as fitness trackers, smart watches and other connected devices in order to wirelessly transmit data without heavily compromising the battery power in a user’s phone.

    WiMax stands for Worldwide Interoperability for Microwave Access. This wireless technology allows data to be transferred at a rate of 30-40 megabits per second. The term refers specifically to interoperable implementations of the IEEE 802.16 wireless family. The technology was once used by several mobile carriers, notably Sprint, to deliver wireless data to its customers. Sprint, along with many of the other carriers who used the technology, has since switched over to using faster LTE 4G networks for data.

    WiFi uses radio waves (RF) to allow two devices to communicate with one another. The technology is most commonly used to connect Internet routers to devices like computers, tablets and phones; however, it can be used to connect together any two hardware components. WiFi is a local wireless network that runs of the 802.11 standards set forth by the Institute of Electrical and Electronics Engineers (IEEE).

    Adapted from:
    "Chapter 8 Device Drivers" by Multiple Contributors, The Linux Documentation Project is in the Public Domain, CC0
    "Thin client" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0
    "USB" by Multiple ContributorsWikipedia is licensed under CC BY-SA 3.0

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