exam1 quizlet

What is an operating system (OS)?

A program that acts as an intermediary between a computer user and the computer hardware.

What is the primary purpose of an operating system?

To provide an environment in which users can execute programs.

What is the primary goal of an operating system?

To make the computer system convenient to use.

What is the secondary goal of an operating system?

To make the computer system efficient to use.

What are the four main components of a computer system?

Hardware, operating system, application programs, and users.

What does computer hardware provide?

Basic computing resources, such as the CPU, memory, and I/O devices.

What is the role of the operating system in a computer system?

It controls and coordinates hardware resources among application programs and users.

What are application programs?

Programs that use system resources to solve users' computing problems, such as compilers, database systems, and video games.

Who or what can be a computer system user?

People, machines, or other computers.

What does it mean to view the OS as an extended machine?

The OS abstracts complex hardware details and provides easier, more convenient interfaces for programs.

Why is the OS described as a virtual or abstract machine?

It hides low-level hardware details and provides hardware-independent interfaces.

What are two benefits of the OS acting as an extended machine?

Greater portability and protection, with programming that is easier and less error-prone.

What does it mean to view the OS as a resource manager?

The OS coordinates and controls limited resources, resolves conflicts, promotes fairness, and aims for efficient access.

What are examples of resources managed by an OS?

Memory, disk storage, CPU time, and network resources.

What are common parts or functions of an operating system?

Memory management, I/O management, CPU scheduling, IPC, and multitasking or multiprogramming.

What is the kernel?

The core part of an operating system that may provide essential OS functionality.

Why might an OS include features beyond its core functions?

Features such as file systems, multimedia support, and user interfaces provide additional functionality and convenience.

What were the four generations of OS development discussed in the slides?

First generation: punched cards; second: transistors and batch systems; third: integrated circuits and advanced OS techniques; fourth: personal computers.

What is the fifth generation described in the slides?

Parallel systems using multiple processors.

What characterized first-generation computing?

Punched-card-based computing.

What characterized second-generation computing?

Transistors and batch systems.

What technologies and concepts emerged during the third generation?

Integrated circuits, spooling, multiprogramming, multitasking, and virtual memory.

What is spooling?

Simultaneous Peripheral Operation On-Line; using disk storage as a buffer to overlap I/O work with computation.

What does spooling stand for?

Simultaneous Peripheral Operation On-Line.

How does spooling improve system efficiency?

It allows I/O for one job to overlap with computation for another job.

How could a disk be used during spooling?

It could hold the next job from a card reader and buffer output waiting to be printed while another job executes.

What is a job pool?

A data structure containing information and pointers to jobs stored on disk.

Why did disk storage enable a job pool?

Disk supports random access, allowing multiple jobs to wait on disk rather than relying on sequential access like cards or tape.

Why is job scheduling useful?

It determines the order in which jobs run and can increase CPU utilization.

What is multiprogramming?

Keeping multiple jobs in memory so the CPU can switch to another job when the current job waits for I/O.

How does multiprogramming improve CPU utilization?

The CPU can perform work for another job instead of sitting idle while one job waits for I/O.

How is memory used in multiprogramming according to the slides?

Memory is partitioned into several pieces to hold multiple jobs.

What is multitasking, also called time-sharing?

An extension of multiprogramming that switches between jobs using a timer to support user interaction.

What triggers a task switch in the multitasking model described in the slides?

A timer can trigger a switch, rather than switching only when a job waits for I/O.

Why was multitasking developed?

To support user interactivity and responsive computer use.

What trade-off must time-sharing systems balance?

CPU utilization versus response time.

What does a time-sharing system allow users to do?

Interact with the computer through devices such as a keyboard and display while programs run.

Why is a file system important in multitasking systems?

It allows users and programs to access stored data and code.

What is virtual memory?

A technique that allows programs to be larger than physical memory by loading needed portions into memory and moving inactive portions to disk.

How does virtual memory handle programs larger than RAM?

It loads program parts into memory as needed and can swap inactive program or data portions to disk.

What is the main benefit of treating memory space uniformly in virtual memory?

Programs can use a consistent memory-space abstraction instead of managing physical memory directly.

What major computer-system development characterized the fourth generation?

Personal computers, generally designed for a single user.

What priorities were important for fourth-generation personal computers?

User convenience and responsiveness.

What are parallel systems?

Systems that use multiple processors in close communication.

What is a tightly coupled system?

A system whose processors share memory and a clock and usually communicate through shared memory.

What are three advantages of parallel systems?

Increased throughput, economy, and increased reliability.

What is throughput in the context of parallel systems?

The amount of work completed over a period of time.

What is graceful degradation?

A system continues providing service at a reduced level when some components fail.

What is a fail-soft system?

A system designed to continue operating, possibly with reduced functionality, when failures occur.

What is symmetric multiprocessing (SMP)?

A system in which each processor runs an identical copy of the operating system.

What is an advantage of symmetric multiprocessing?

Multiple processes can run at once without the performance deterioration associated with relying on a single processor.

What is asymmetric multiprocessing?

A system in which processors have assigned tasks, with a master processor scheduling and allocating work to other processors.

What is the key difference between SMP and asymmetric multiprocessing?

SMP processors run identical OS copies, while asymmetric multiprocessing assigns processors specific roles, often with a master coordinating the others.

What is a real-time system?

A system used for a dedicated application in which results must satisfy defined timing constraints.

What does deterministic mean in the context of real-time systems?

The system has well-defined, fixed-time constraints.

What is a hard real-time system?

A real-time system in which strict timing constraints must be met.

What does the PowerPoint state about secondary storage in hard real-time systems?

It may be limited or absent, with data stored in short-term memory or ROM.

Why can hard real-time requirements conflict with time-sharing?

Strict timing constraints can conflict with the scheduling and responsiveness trade-offs of time-sharing systems.

What is a soft real-time system?

A real-time system with less strict timing requirements than a hard real-time system.

What applications may benefit from soft real-time systems?

Multimedia and virtual reality applications.

What is a distributed system?

A system that distributes computation among several physical processors.

What is a loosely coupled system?

A system in which each processor has its own local memory and processors communicate through communication links.

How do processors in a loosely coupled system communicate?

Through communication lines such as high-speed buses or telephone lines.

What are four advantages of distributed systems?

Resource sharing, computation speedup through load sharing, reliability, and communication.

What is a Network Operating System?

An OS that provides network file sharing and communication while each computer continues to run independently.

What is a Distributed Operating System?

An OS that coordinates computers with less autonomy and gives the impression that one operating system controls the network.

What is the key difference between a Network OS and a Distributed OS?

A Network OS keeps computers operating independently, while a Distributed OS makes the computers appear more like one coordinated system.

What does IPC stand for?

Interprocess Communication.

What is CPU scheduling?

The OS function of deciding which process or job should use the CPU next.

What is memory management?

The OS function of managing the use and allocation of memory.

What is I/O management?

The OS function of coordinating input and output devices and operations.

Why is operating-system design a software engineering problem?

It involves designing abstractions, developing the kernel, improving usability, and creating efficient algorithms.

Why do computer scientists study operating systems?

To understand OS components, compare OS designs, and develop algorithms that improve efficiency.