Computers Chapter 9

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False - Linuix is open source software

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additional programs and apps included with operating system, usually for profit

segment of memory or storage in which items are placed while waiting to be transferred from an input device or to an output device

set of commands used to control actions performed in a command-line interface

operating system that runs on computers and mobile devices provided by a variety of manufacturers

small program that tells the operating system how to communicate with a specific device

ROM chips or flash memory chips that store permanent instructions

software whose code is provided for use, modification, and redistribution

software that is privately owned and limited to a specific vendor or computer or device model

A version of Linuix built for Raspberry Pi

operating system problem that occurs when it spends much of its time paging, instead of executing application software

An operating system (OS) is a set of programs that coordinate all the activities among computer or mobile device hardware. Most operating systems perform similar functions that include starting and shutting down a computer or mobile device, providing a user interface, managing programs, managing memory, coordinating tasks, configuring devices, monitoring performance, establishing an Internet connection, providing file management and other device or media-related tasks, and updating operating system software. Some operating systems also allow users to control a network and administer security.

Firmware consists of ROM chips or flash memory chips that store permanent instructions. The operating system that a computer uses sometimes is called the platform because applications are said to run "on top of" it, or because the platform supports the applications.

The process of starting or restarting a computer or mobile device is called booting. Some people use the term cold boot to refer to the process of starting a computer or mobile device from a state when it is powered off completely. Similarly, warm boot refers to the process of restarting a computer or mobile device while it remains powered on. A warm boot generally is faster than a cold boot because it skips some of the operating system start-up instructions that are included as part of a cold boot.

Step 1: When you turn on the computer or mobile device, the power supply or battery sends an electrical current to circuitry in the computer or mobile device. Step 2: The charge of electricity causes the processor chip to reset itself and finds the firmware that contains start-up instructions. Step 3: The start-up process executes a series of tests to check the various components. These tests vary depending on the type of computer or devices and can include checking the buses, system clock, adapter cards, RAM chips, mouse, keyboard, and drives. It also includes making sure that any peripheral devices are connected properly and operating correctly. If any problems are identified, the computer or device may beep, display error messages, or cease operating — depending on the severity of the problem. Step 4: If the tests are successful, the kernel of the operating system and other frequently used instructions load from the computer or mobile device's internal storage media to its memory (RAM). The kernel is the core of an operating system that manages memory and devices, maintains the internal clock, runs programs, and assigns the resources, such as devices, programs, apps, data, and information. The kernel is memory resident, which means it remains in memory while the computer or mobile device is running. Other parts of the operating system are nonresident; that is, nonresident instructions remain on a storage medium until they are needed, at which time they transfer into memory (RAM). Step 5: The operating system in memory takes control of the computer or mobile device and loads system configuration information. The operating system may verify that the person attempting to use the computer or mobile device is a legitimate user. Finally, the user interface appears on the screen, and any start-up applications, such as antivirus software, run.

The kernel is the core of an operating system. Memory resident means it remains in memory while the computer or mobile device is running. Other parts of the operating system are nonresident; that is, nonresident instructions remain on a storage medium until they are needed, at which time they transfer into memory (RAM).

A boot drive is the drive from which your personal computer starts, which typically is an internal hard drive, such as a hard disk or SSD. Sometimes, an internal hard drive becomes damaged and the computer cannot boot from it, or you may want to preview another operating system without installing it. In these cases, you can start the computer from a boot disk, which is removable media, such as a CD or USB flash drive, that contains only the necessary operating system files required to start the computer.

Some users choose to shut down their computers and mobile devices regularly. These users might be concerned with security, want to reduce energy costs, or prefer to clear memory often. Sleep mode saves any open documents and running programs or apps to RAM, turns off all unneeded functions, and then places the computer in a low-power state. If, for some reason, power is removed from a computer or device that is in sleep mode, any unsaved work could be lost. Hibernate mode, by contrast, saves any open documents and running programs or apps to an internal hard drive before removing power from the computer or device.

A user interface (UI) controls how you enter data and instructions and how information is displayed on the screen. With a graphical user interface (GUI), you interact with menus and visual images by touching, pointing, tapping, or clicking buttons and other objects to issue commands. Many current GUI operating systems incorporate features similar to those of a browser, such as links and navigation buttons (i.e., Back button and Forward button) when navigating the computer or mobile device's storage media to locate files. With a natural user interface (NUI), users interact with the software through ordinary, intuitive behavior. NUIs are implemented in a variety of ways: touch screens (touch input), gesture recognition (motion input), speech recognition (voice input), and virtual reality (simulations). In a command-line interface, a user types commands represented by short keywords or abbreviations (such as dir to view a directory, or list of files) or presses special keys on the keyboard (such as function keys or key combinations) to enter data and instructions. Some people consider command-line interfaces difficult to use because they require exact spelling, form, and punctuation. Minor errors, such as a missing period, generate an error message.

When a computer is running multiple programs concurrently, one program is in the foreground and the others are in the background. The one in the foreground is the active program, that is, the one you currently are using. The other programs running but not in use are in the background. The foreground program typically is displayed on the screen, and the background programs are hidden partially or completely behind the foreground program. A multitasking operating system's user interface easily allows you to switch between foreground and background programs.

To remove a program or app: Sign in to a user account that has administrative privileges; that is, the user account should have the capability to perform functions such as removing programs or apps. Make sure the program or app you want to remove is not running. Display the list of programs or apps installed on your computer or mobile device. Select the program or app you wish to remove. Click the button to remove the program or app. If necessary, when the installation is complete, restart your computer or device. Verify the program or app you removed no longer is on your computer or mobile device.

The purpose of memory management is to optimize the use of a computer or device's internal memory, that is, RAM. RAM (random access memory) consists of one or more chips on the motherboard that hold items such as data and instructions while the processor interprets and executes them. The operating system allocates, or assigns, data and instructions to an area of memory while they are being processed. Then, it carefully monitors the contents of memory. Finally, the operating system releases these items from being monitored in memory when the processor no longer requires them. With virtual memory, the operating system allocates a portion of a storage medium, such as a hard drive or a USB flash drive, to function as additional RAM. As you interact with a program, part of it may be in physical RAM, while the rest of the program is on the hard drive as virtual memory. Because virtual memory is slower than RAM, users may notice the computer slowing down while it uses virtual memory.

The technique of swapping items between memory and storage is called paging

When an operating system spends much of its time paging, instead of executing application software, it is said to be thrashing. To prevent thrashing: Remove unnecessary files and uninstall seldom used programs and apps. If your computer has a hard disk (instead of an SSD), try defragmenting the hard disk. Purchase and install additional RAM.

If a mobile device runs low on memory: Exit unnecessary applications that are running. Restart the smartphone or mobile device. Uninstall seldom used applications. Download and install an app that identifies and removes unused files, duplicate or blurry photos, and downloaded app files you no longer need on the phone. Remove unnecessary files, including photos and videos (you may want to copy them to cloud storage, a computer, or a memory card first). If your smartphone supports the use of a memory card, specify that applications, photos, videos, or downloaded files should be saved on a memory card instead of the smartphone's internal memory.

The operating system determines the order in which tasks are processed. A multiuser operating system does not always process tasks on a first-come, first-served basis. If a user or task has been assigned a higher priority than others by the network administrator, the operating system performs higher-priority tasks first. Sometimes, a device already may be busy processing one task when it receives a request to perform a second task. While waiting for devices to become idle, the operating system places items in buffers. A buffer is a segment of memory or storage in which items are placed while waiting to be transferred from an input device or to an output device. An operating system commonly uses buffers with printed documents. This process, called spooling, sends documents to be printed to a buffer instead of sending them immediately to the printer. Multiple documents line up in a queue in the buffer.

A driver, short for device driver, is a small program that tells the operating system how to communicate with a specific device. Each device connected to a computer, such as a mouse, keyboard, monitor, printer, card reader/writer, digital camera, webcam, portable media player, or smartphone, has its own specialized set of commands and, thus, requires its own specific driver. When you start a computer or connect a device via a USB port, the operating system loads the device's driver. Drivers must be installed for each connected device in order for the device to function properly. To find the latest drivers: Search for and navigate to the device manufacturer's website. Click the link on the website to display the webpage containing technical support information. Select or enter the device's model number to display support information for the device. Browse the device's support information and then click the link or button to download the most current driver. Manufacturers often create different versions of drivers for different operating systems, so make sure you download the driver that is compatible with the operating system you currently are using. When the download is complete, follow the instructions that accompanied the driver to install it.

A performance monitor is a program that assesses and reports information about various computer resources and devices. For example, users can monitor the processor, drives, network, and memory usage. The information in performance reports helps users and administrators identify a problem with resources so that they can try to resolve any issues.

Operating systems typically provide a means to establish Internet connections. You can establish wired connections, such as cable and DSL, or wireless connections, such as Wi-Fi, mobile broadband, and satellite. Some connections are configured automatically as soon as you connect to the Internet. With others, you may need to set up a connection manually.

OEMs (original equipment manufacturers) often include and profit from including extra programs installed with a computer or device's operating system. These additional programs and apps, often called bloatware, mostly are harmless. Users object to their inclusion, however, because these programs and apps take up space, may slow start-up time, and can decrease the computer or device's overall efficiency. Some programs or apps cause nuisances for the user, such as those that display alarming messages about a computer's virus protection and then offer more protection for additional costs. Programs that run when the operating system starts or run in the background cause unnecessary slowdowns. Independent software developers post fixes to remove bloatware. These fixes may or may not be legal, depending on your license agreement, and could violate any warranties for which you may be eligible. Critics state that OEMs and operating system manufacturers should offer users the option to purchase a computer or device with a clean installation (without bloatware) of the operating system.

Operating system automatic updates can include fixing program errors, improving program functionality, expanding program features, enhancing security, and modifying device drivers. The automatic update option occasionally has caused problems. In one case, people preparing their income tax returns were unable to print forms when a leading software company issued an automatic update one week before the filing deadline. In another situation, an automatic update was installed on all computers — even those with this feature disabled. The company claimed that the update was harmless and was for the benefit of its customers. Only later did some users realize that this secret update caused serious problems. One problem, ironically, was that updates no longer could be installed on the affected computers.

A file manager performs functions related to displaying files; organizing files in folders; and copying, renaming, deleting, moving, and sorting files. The search tool attempts to locate files on your computer or mobile device based on specified criteria. An image viewer displays, copies, and prints the contents of graphics files. An uninstaller removes a program or app as well as any associated entries in the system files. The disk cleanup tool searches for and removes unnecessary files. A disk defragmenter reorganizes the files and unused space on a computer's hard disk so that the operating system accesses data more quickly and programs and apps run faster. A screen saver causes a display's screen to show a moving image or blank screen if no keyboard or mouse activity occurs for a specified time. A file compression tool shrinks the size of a file(s). A PC maintenance tool identifies and fixes operating system problems, detects and repairs drive problems, and includes the capability of improving a computer's performance. The backup and restore tool copies selected files or the contents of an entire storage medium to another storage location. A power management tool monitors a laptop or mobile device's battery usage.

Operating system security tools include firewall, automatic updating, antivirus software, and spyware and malware detection software.

The network administrator, the person overseeing network operations, uses the server operating system to add and remove users, computers, and other devices to and from the network. The network administrator also uses the operating system on the network to configure the network, install software, and administer network security.

Network administrators, as well as owners of computers, typically have an administrator account that enables them to access all files and programs, install programs, and specify settings that affect all users on a computer, mobile device, or network. Settings include creating user accounts and establishing permissions. For each user, the network administrator or computer owner establishes a user account, which enables a user to sign in to, or access resources on, a network or computer.

Permissions define who can access certain resources and when they can access those resources.