CH 1. Operating Systems Fundamentals
real-time operating system (RTOS)
An operating system that receives and processes inputs and produces the required outputs in a specified amount of time.
time-sharing system
A central computer system, such as a mainframe, that is used by multiple users and applications simultaneously.
user interface
A component of an operating system that provides a method for users to interact with the computer, usually with a keyboard and mouse or touch screen.
preemptive multitasking
A computer hardware and software design for multitasking of applications in which the operating system retains control of the computer at all times. See cooperative multitasking for comparison.
client/server systems
A computer hardware and software design in which different portions of an application execute on different computers, or on different components of a single computer
cooperative multitasking
A computer hardware and software design in which the operating system temporarily hands off control to an application and waits for the application to return control to the operating system
single-tasking
A computer hardware and software design that can manage only a single task at a time
multiuser system
A computer hardware and software system designed to service multiple users who access the computer's hardware and software applications simultaneously
single-user system
A computer hardware and software system that enables only one user to access its resources at a particular time
desktop operating system
A computer operating system that is typically installed on a PC, usually used by one person at a time, and may or may not be connected to a network. Also called a client operating system.
server operating system
A computer operating system usually found on more powerful PC-based computers than those used for desktop operating systems. A server OS is connected to a network and can act in many roles to enable multiple users to access information via e-mail, files, software, and other means
sequential processing
A computer processing style in which each operation is submitted, acted upon, and the results displayed before the next process is started. Compare to batch processing
embedded system
A computer that has a dedicated function within a larger system, such as a piece of machinery.
supercomputer
A computer that has extreme processing power and speed to handle complex computations that are beyond the reach of other computers.
batch processing
A computing style frequently employed by large systems. A request for a series of processes is submitted to the computer.
cloud computing
A computing technology that provides a host of scalable Web-based applications and services over the Internet or a private network used by clients through Web browsers
task switching
A hybrid between single-tasking and multitasking that permits the user or application software to switch among multiple single-tasking operations.
blade enclosure
A large box with slots for blade servers; the box also provides cooling fans, electrical power, connection to a shared monitor and pointing device, and even network connectivity. The actual design depends on the manufacturer
service
A process that runs in the background because there is no user interface.
process
A program that is loaded into memory and run by the CPU. It can be an application a user interacts with, such as a word-processing program or a Web browser, or a program with no user interface that communicates with other processes and provides services to them.
computer program
A series of instructions executed by the computer's CPU.
blade server
A server unit that looks like a card that fits into a blade enclosure.
operating system (OS)
A specialized computer program that provides a user interface, file system, services, and a kernel to a computer. An OS runs on computer hardware and facilitates application execution.
multitasking
A technique that allows a computer to run two or more programs at the same time.
complementary metal oxide semiconductor (CMOS)
A type of memory that stores a computer's BIOS configuration
Beginner's All-purpose Symbolic Instruction Code (BASIC)
An English-like computer programming language originally designed as a teaching tool, but which evolved into a useful and relatively powerful development language.
application software
An application that a user runs on a computer. Application software consists of computer code that is formatted so the computer or its operating system can translate the code into a specific task.
kernel
An essential set of programs and computer code built into a computer operating system to control processor, disk, memory, and other functions central to a computer's basic operation. The kernel communicates with the BIOS, device drivers, and the API to perform these functions. It also interfaces with the resource managers.
graphical user interface (GUI)
An interface between the user and an operating system that presents information in an intuitive graphical format, including multiple colors, figures, icons, windows, toolbars, and other features.
command-line interface (CLI)
An interface that enables the user to display a command line from which to enter commands.
shell
An interface that enables users to interact with an operating system kernel. The shell enables the user to execute commands
distribution
An issuance of UNIX or Linux that is based on a standard kernel, but that also has customizations added by a particular private or commercial development group. AKA Distro.
rack-mounted server
CPU boxes mounted in racks that can hold multiple servers, each with its own power cord and network connection—and that often share one monitor and pointing device.
device driver
Computer software designed to provide the operating system and application software access to specific computer hardware.
application programming interface (API)
Functions or programming features in an operating system that programmers can use for network links, links to messaging services, or interfaces to other systems.
input/output (I/O)
Input is information taken in by a computer device to handle or process; an example is characters typed at a keyboard. Output is information sent out by a computer device after the information is handled or processed; an example is the display of typed characters on the monitor.
basic input/output system (BIOS)
Low-level program code that conducts basic hardware and software communications inside the computer.
read-only memory (ROM)
Memory that contains information that is not erased when the power is removed from the memory hardware.
resource managers
Programs that manage computer memory and CPU use
multithreading
Running several program processes or parts (threads) at the same time.
power-on self test (POST)
Tests, such as memory and hardware component tests, that are run by the BIOS when a computer starts and that must complete before the operating system is loaded. See basic input/output system (BIOS).
Microsoft Disk Operating System (MS-DOS)
The first widely distributed operating system for microcomputers, created by Tim Paterson and a team at Microsoft that included Bill Gates. This generic computer code was used to control many basic computer hardware and software functions. MS-DOS is sometimes referred to as DOS.
file system
The method by which an OS stores and organizes files and manages access to files on a storage device.
hardware
The physical devices in a computer, including the CPU, circuit boards (cards), disk drives, monitor, and modem.
