What 4 things does an operating system do?

Answer 1

Process management
Every action on a computer, be it background services or applications, is run inside a process. Older operating systems such as DOS could only run one process at a time. Modern operating systems are able to run many at once (multi-tasking). Process management is an operating system's way of dealing with running multiple processes. Since most computers contain one processor with one core, multi-tasking is accomplished by simply switching processes quickly. As a user runs more processes, all timeshares become smaller. On many systems, this can eventually lead to problems such as skipping of audio or jittery mouse movement. Process management involves the computation and distribution of "timeshares". Most operating systems allow a process to be assigned a process priority which impacts its timeshare.

2.Memory management
According to Parkinson's law "Programs expand to fill the memory available to hold them". Thus the programmers like a memory of infinite size and infinite speed. Nowadays most of the computer's memory is arranged in a hierarchial manner, starting from fastest registers, cache, RAM and lastly slowest disk storage. The memory manager in a OS coordinates the memories by tracking which one is available, which is to be allocated or deallocated and how to swap between the main memory and secondary memories.

3.Disk and file systems
Both Linux and Microsoft operating systems have a variety of native file systems. Linux has a greater range of native file systems, those being: ext2, ext3, ReiserFS, Reiser4, GFS, GFS2, OCFS, OCFS2, NILFS and Google File System. Linux also has full support for XFS and JFS, along with the FAT file systems, and read support for NTFS. Windows on the other hand has limited file system support which only includes: FAT12, FAT16, FAT32, and NTFS. The NTFS file system is the most efficient and reliable of the four Windows systems. All the FAT systems are older than NTFS and have limitations on the partition and file size that can cause a variety of problems.

Within each variation of each operating systems file system there are two ways it can be allocated. Each system can be journaled or non-journaled. Journaled being the safer alternative under the circumstances of a system recovery. If a system comes to an abrupt stop, in a system crash scenario, the non-journaled system will need to undergo an examination from the system check utilities where as the journaled file systems recovery is automatic. Microsoft's NTFS is journaled along with most Linux file systems, except ext2, but including ext3, reiserfs and JFS.

Every file system is made up of similar directories and subdirectories. Along with the operating systems file system similarities there are the subtle differences. Microsoft separates its directories with a back slash and its file names aren't case sensitive whereas Linux uses the standard forward slash and its file names are case sensitive.

4.Networking
Most operating systems are capable of using the now-universal TCP/IP networking protocols. This means that one system can appear on a network of the other and share network hardware such a printers and scanners.

Many operating systems also support one or more vendor-specific legacy networking protocols as well, for example, SNA on IBM systems, DECnet on systems from Digital Equipment Corporation, and Microsoft-specific protocols on Windows. Specific protocols for specific tasks may also be supported such as NFS for file access.

5.Security-Security as it pertains to the operating system is the ability to authenticate users prior to access, categorize the level of access the user has, and limit access based on a policy placed by administration. Typically an operating system offers (hosts) various services to other network computers and users. These services are usually provided through ports or numbered access points beyond the operating systems network address. Typically services include offerings such as file sharing, print services, email, web sites, and file transfer protocols.

At the front line of security are hardware devices known as firewalls. At the operating system level there are various software firewalls. A software firewall is configured to allow or deny traffic to a service running on top of the operating system. Therefore one can install and be running an insecure service, such as telnet or ftp, and not have to be threatened by a security breach because the firewall would deny all traffic trying to connect to the service on that port.

6.Graphical user interfaces
Today, most modern operating systems contain Graphical User Interfaces. A few older operating systems tighly integrate the user interface to the kernel, for example, the original implementations of Windows and MacOS. More modern operating systems are modular separating the graphics subsystem from the kernel (as is now done in MacOS/X and all Windows versions based on Windows/NT)

Many operating systems allow the user to install or create any user interface they desire. X Windows is a commonly found interface on many Unix-based systems while GNOME and KDE are commonly found on Linux systems as well as some Unix systems.

GUIs tend to change with time. For example, Windows has modified its GUI every time a new major version of Windows is released and the MacOS GUI changed dramatically with the introduction of MacOS/X.

6.Device drivers-A device driver is a specific type of computer software developed to allow interaction with hardware devices. Typically this constitutes an interface for communicating with the device, through the specific computer bus or communications subsystem that the hardware is connected to, providing commands to and/or receiving data from the device, and on the other end, the requisite interfaces to the operating system and software applications. It is a specialized hardware dependent computer program which is also operating system specific that enables another program, typically an operating system or applications software package or computer program running under the operating system kernel, to interact transparently with a hardware device, and usually provides the requisite interrupt handling necessary for any necessary asynchronous time-dependent hardware interfacing needs.

The key design goal of device drivers is abstraction. Every model of hardware (even within the same class of device) is different. Newer models also are released by manufacturers that provide more reliable or better performance and these newer models are often controlled differently. Computers and their operating systems cannot be expected to know how to control every device, both now and in the future. To solve this problem, OSes essentially dictate how every type of device should be controlled. The function of the device driver is then to translate these OS mandated function calls into device specific calls. In theory a new device, which is controlled in a new manner, should function correctly if a suitable driver is available. This new driver will ensure that the device appears to operate as usual from the operating systems' point of view.

http://en.wikipedia.org/wiki/Operating_system

Answer 2

I dont know if these are the exact 4 you are looking for, but these are the major roles that first come to mind:
1) Interfaces with the hardware of the physical computer to provide input (keyboard, mouse, etc) and output (monitor, printer, etc) functionality.
2) Provides a User Interface for people to interact with the system.
2) Provides an environment for Applications to be loaded and executed.
4) Allocates the computer's processing power, memory, storage, and other system resources between Applications (and itself)

If you dont want to take my work for it, then this page might prove helpful:
http://www.webopedia.com/TERM/o/operating_system.html

Answer 3

Process complex code (Manages other programs)
Controls the hardware peripherals (like keyboards and managing files on the hard drive)
Supplies output in some form
Takes in input in some form


*shrug* If you are asking a question out of a book, read closer for the exact answer.

Answer 4

Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

Answer 5

uhh more than a billion executioins per seond depends on speed well 3.3 ghz processor would allow the computer to do a full 3,300,000,000 execututions per second belicve it or not im 14 and i did a science fair project on this crap computations per second and how thse effect cpu speed and temp also the max executions p/sec
so the average computations pers secondare about 2 billion 7 hundred million executions per seond about 1 ghz billion exe. is used on 10 progs liike limewire so one prog can go to any exe, limewire allone would be using 200 million exe. out of 3 billion if its idle about 100 million exe per second i had to reasearch this crap for three months i ended up winning third place with 60 bucks got me self a new 16xdual layer dvd burner litoen

Answer 6

- determines how valuable RAM is alloted to programs
- performs task related to file management
- sets priorities for handling tasks
- manages the flow of instructions, data, and information to and from the processor

the objectives of the operating system are the following:
- to facilitate communication between the computer system and the people who run it
- to facilitate communication among computer system components
- to maximize throughput
- to minimize the time needed to execute a user command
- to optimize the use of computer system resources
- to keep track of all files in disk storage
- to provide an envelope of security for the computer system
- to monitor all systems capabilities and alert the user system failure or potential problems

Answer 7

1-4. An interface between yourself and the hardware and software of your computer.

Answer 8

The basic roll of an OS is to just let your hardware "talk" to your software.

Answer 9

It does many more things than 4.The biggest and main thing it does, is allow you to use your computer PERIOD.