Found 691 Articles for Computer Science

I/O devices are very important in the computer systems.They provide users the means of interacting with the system. So there is a separate I/O system devoted to handling the I/O devices.The different Components of the I/O systems are −I/O HardwareThere are many I/O devices handled by the operating system such as mouse, keyboard, disk drive etc. There are different device drivers that can be connected to the operating system to handle a specific device. The device controller is an interface between the device and the device driver.A diagram to represent this is −I/O Application InterfaceThe user applications can access all ... Read More

Protection and security requires that computer resources such as CPU, softwares, memory etc. are protected. This extends to the operating system as well as the data in the system. This can be done by ensuring integrity, confidentiality and availability in the operating system. The system must be protect against unauthorized access, viruses, worms etc. Threats to Protection and Security A threat is a program that is malicious in nature and leads to harmful effects for the system. Some of the common threats that occur in a system are − Virus Viruses are generally small snippets of code embedded in a ... Read More

A computer system uses many devices, arranged in different ways to solve many problems. This constitutes a computing environment where many computers are used to process and exchange information to handle multiple issues.The different types of Computing Environments are −Let us begin with Personal Computing Environment −Personal Computing EnvironmentIn the personal computing environment, there is a single computer system. All the system processes are available on the computer and executed there. The different devices that constitute a personal computing environment are laptops, mobiles, printers, computer systems, scanners etc.Time Sharing Computing EnvironmentThe time sharing computing environment allows multiple users to share ... Read More

Storage management plays an important part in operating system. It deals with the storage procedures in the computer system using an operating system. Details about this is as follows −Memory ManagementMemory management plays an important part in operating system. It deals with memory and the moving of processes from disk to primary memory for execution and back again.The most important concepts in memory management are paging and segmentation. Details about these topics are given below −PagingIn a computer system, virtual memory can be created that is more than the actual memory available i.e. physical memory. To implement this, the concept ... Read More

Files are used to provide a uniform view of data storage by the operating system. All the files are mapped onto physical devices that are usually non volatile so data is safe in the case of system failure.File AttributesThe attributes of a file may vary a little on different operating systems. However, the common file attributes are −NameThis denotes the symbolic name of the file. The file name is the only attribute that is readable by humans easily.IdentifierThis denotes the file name for the system. It is usually a number and uniquely identifies a file in the file system.TypeIf there ... Read More

Open Source operating systems are released under a license where the copyright holder allows others to study, change as well as distribute the software to other people. This can be done for any reason. The different open source operating system available in the market are −CosmosThis is an open source operating system written mostly in programming language C#. Its full form is C# Open Source Managed Operating System. Till 2016, Cosmos did not intend to be a fully fledged operating system but a system that allowed other developers to easily build their own operating systems. It also hid the inner ... Read More

There are two modes of operation in the operating system to make sure it works correctly. These are user mode and kernel mode.A diagram that illustrates the transition from user mode to kernel mode and back again is as follows −The following are the modes −User Mode:The system is in user mode when the operating system is running a user application such as handling a text editor. The transition from user mode to kernel mode occurs when the application requests the help of operating system or an interrupt or a system call occurs.The mode bit is set to 1 in ... Read More

Supervisor mode or privileged mode is a computer system mode in which all instructions such as privileged instructions can be performed by the processor. Some of these privileged instructions are interrupt instructions, input output management etcThe privilege levels of different components in a system is given as follows −The kernel is the most privileged part of the computer system. There are some privileged instructions that can only be executed in kernel mode or supervisor mode. The the privilege reduces for device drivers and applications respectively.Features of Supervisor ModeSome of the important features of supervisor mode are as follows −Supervisor mode ... Read More

An operating system is a construct that allows the user application programs to interact with the system hardware. Since the operating system is such a complex structure, it should be created with utmost care so it can be used and modified easily. An easy way to do this is to create the operating system in parts. Each of these parts should be well defined with clear inputs, outputs and functions.Simple StructureThere are many operating systems that have a rather simple structure. These started as small systems and rapidly expanded much further than their scope. A common example of this is ... Read More

A beowulf cluster is formed using normal computers that are identical. These are arranged into a small local area network (LAN). There are programs that allow these computers to share processing among them.So beowulf clusters form a parallel processing unit using common personal computers.An image that displays the first beowulf cluster at Barcelona Supercomputing Center is as follows −Image Credit − By Vcarceler [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia CommonsFeatures of Beowulf ClustersSome important features of beowulf clusters are as follows −Beowulf clusters are formed using normal computers. There is no software that denoted a cluster as a beowulf cluster.A ... Read More