Operating Systems: Chapter 1 - Key Terms
Real-time System
An operating system that interacts directly with the user and responds in realtime with required information.
Copy backup
A backup that copies selected files to the selected medium without marking files as backed up
Time-Sharing System
A central computer system, such as a mainframe, that is used by multiple users and applications simultaneously.
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. Typically, client software supports user I/O, and server software conducts database searches, manages printer output, and the like.
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. Compare to preemptive multitasking.
Single-tasking
A computer hardware and software design that can manage only a single task a time.
Multiuser System
A computer hardware and software system designed to service multiple users who access the computers hardware and software applications simultaneously.
Single-User System
A computer hardware and software system that enables only one user access its resources at a particular time.
Desktop Operating System
A computer operating system that typically is installed on a PC type of computer, usually used by one person at a time, that may or may not be connected to a network.
Server Operating System
A computer operating system usually found on more powerful PC-based computers than those used for desktop operating systems, which is connected to a network, and that can act in many roles to enable multiple users to access information, such as e-mail, files, and software.
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.
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; information is displayed or printed when the batch is complete. Batches might include processing all of the checks submitted to a bank for a day, or all of the purchases in a wholesale inventory system, for example. Compare to sequential processing
Cloud computing
A computing technology that provides a host of scalable Web-based applications and services over the Internet or a private network that is 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 and the box provides cooling fans, electrical power, connection to a shared monitor and pointing device, and even network connectivity. The actual design depends on the manufacturer.
Blade Server
A server unit that looks like a card that fits into a blade enclosure. Blade servers are intended to save space. See blade enclosure.
Multitasking
A technique that allows a computer to run two or more programs at the same time.
(CMOS) Complementary Metal Oxide Semiconductor - memory
A type of NVRAM (nonvolatile random access memory) that uses a low-power technology and when employed to store the BIOS in a computer, it is powered by a small battery. See non-volatile RAM.
Application software
A word processor, spreadsheet, database, computer game, or other type of application that a user runs on a computer. Application software consists of computer code that is formatted so that the computer or its OS can translate that code into a specific task, such as writing a document.
(BASIC)Beginner's All-purpose Symbolic Instruction Code
An English-like computer programming language originally designed as a teaching tool, but which evolved into a useful and relatively powerful development language.
Kernel
An essential set of programs and computer code built into a computer OS to control processor, disk, memory, and other functions central to the basic operation of a computer. The kernel communicates with the BIOS, device drivers, and the API to preform these functions.
(GUI) Graphical User Interface
An interface between the user and an OS, which presents information in an intuitive graphical format that employs multiple colors, figures, icons, windows, toolbars, and other features. A GUI is usually deployed with a pointing device, such as a mouse , to make the user more productive.
Command-line interface
An interface that enables the user to display a command line from which to enter commands, such as through the Command Prompt window in Windows OS and the terminal window in Linux and Mac OS X.
Shell
An interface to enable humans to interact with an operating system kernel. The shell enables the user to execute commands. See kernel.
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.
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.
(NVRAM) Non-Volatile Random Access Memory
Computer memory that does not lose its contents when the power is turned off. One way to ensure non-volatile memory is by connecting the memory to a battery. The BIOS in a computer is typically stored in an NVRAM chip, such as a CMOS chip. See complementary metal oxide semiconductor.
(OS) Operating System
Computer software code that interfaces with user application software and the computer's BIOS to allow the applications to interact with the computer hardware.
Device Driver
Computer software designed to provide the operating system and the application software access to specific computer hardware.
(API) Application Programming Interface
Functions or programming features in an operating system that programmers can use for network links, links to messaging services, or interfaces to other systems.
(I/O) Input/Output
Input is information taken in by a computer device to handle or process, such as characters typed at a keyboard. Output is information sent out by a computer device after that information is handled or processed, such as displaying the character typed at the keyboard.
code
Instructions written in a computer programming language.
(BIOS) Basic Input/Output System
Low-level program code that conducts basic hardware and software communications inside the computer. A computer's BIOS basically resides between computer hardware and the higher level OS, such as UNIX or Windows.
(ROM) Read-Only Memory
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 programs processes or parts (threads) at the same time.
(POST) Power-On Self Test
Tests, such as memory and hardware component tests, that are run by the BIOS when a computer first starts and that must complete before the operating system is loaded. See basic input/output system (BIOS).
(MS-DOS) Microsoft Disk Operating System
The first widely distributed operating system for microcomputers, created by Tim Patterson and a team, including Bill Gates, at Microsoft. This generic computer code used to control many basic computer hardware and software functions. MS-DOS is sometimes referred to as DOS.
Hardware
The physical devices in a computer that you can touch ( if you have the cover off), such as the CPU, circuit boards (cards), disk drives, monitor, and modem.
