OSI represents Open System Interconnection. It was produced by the International Organization for Standardization (ISO) located in Geneva, Switzerland, and the consultative committee for international Telephone and Telegraph (CCITT).OSI was created to develop a frequent standard of network structure throughout the globe. It supports a general idea of inter-process communication so that any open system can technically connect with another accessible framework without any issues. OSI model is a seven-layered architecture model.Advantages of the OSI ModelThe advantages of the OSI Model are as follows −The OSI models clearly define the services, interfaces and protocols. It explains which layer's services are supported. ... Read More

The presentation layer changes the data from an application layer into the device native internal mathematical structure and encodes communicated information into a displayable output format.It executes the code changes, document compressions, security encryption, etc. It also defines the data as per the software/hardware environment of the hub. For instance, demonstrating UNIX structured data in windows.The link between the presentation layer and the application and session layer has been shown in the diagram below −It is concerned with the syntax of data.TranslationThe procedure in two frameworks are generally to exchange the data in the form of character strings, numbers etc. ... Read More

The session layer supports establishing, controlling, and eliminating a session or dialogue between the two end frameworks. It generates the session, handles the packets sent back and forth during the session and removes the session. The dialogue type/session type is also defined through half-duplex or full-duplex.The session layer also supports data synchronization and check pointing so that only the information transmitted after the point of failure should be retransmitted in the event of network failure.This layer also governs the dialogue between the two processes by deciding who can send and who can get at what point during the transmission.The session ... Read More

Physical layer is the shortest layer in the model. This layer is feasible for initiating, preserving, and deactivating a physical circuit between two end frameworks.The Physical Layer is vital for transmitting bits from one device to another device. It can change the series of bits into electric signals, light signals, or electromagnetic signals, relying on either the two hubs on a link circuit, fiber-optic circuit, or microwave/radio circuit.Passive hubs, simple active hubs, terminators, couplers, cables, connectors, repeaters, multiplexers, transmitters and receivers are the devices associated with the physical layer.The physical layer situation for the transmission channel and the data link ... Read More

OSI represents Open System Interconnection. The OSI reference model is a seven-layered architecture and is created in a hugely structured method. Each layer in the model has specific sets of procedures, functions, and protocols. One layer can communicate with an adjacent layer by using its interface.OSI model was advanced by the International Organization for Standardization (ISO) in Geneva, Switzerland, and by the Consultative Committee for International Telephone and Telegraph (CCITT).The figure given below displays the seven-layered Architecture of OSI Models, along with the protocols and interfaces.Functions of the OSI LayersThere are various functions of OSI Layers which are as follows:Physical LayerThis ... Read More

In this post, we will understand the difference between system calls fork and vfork −The ‘fork’ system callIn this system call, the child and parent process have separate memory spaces.The child and parent process are executed simultaneously.This call uses the copy-on-write as alternative.Child process doesn’t have the ability to suspend execution of the parent process in this system call.The page of one process doesn’t get affected by the page of other process.It is more frequently used.No address space is wasted.If the child process alters the page in the address space, it is not visible to the parent process.The ‘vfork’ system ... Read More

In this post, we will understand the difference between symmetric and asymmetric multiprocessing −Asymmetric MultiprocessingIn this kind of multiprocessing, the processors are not considered as equal.The task of the operating system is done by the master processor.There is no communication between the processors since they are controlled by the master processor only.In this multiprocessing, process follow the master-slave pattern.The systems are relatively inexpensive.This kind of multiprocessing systems are easier to design.Symmetric MultiprocessingIn this kind of multiprocessing, all the processors are considered equal.The tasks of the operating system are done by individual processors.All the processors communicate with each other since they ... Read More

In Operating Systems, Preemptive Scheduling is a type of CPU scheduling method in which the CPU is allocated for a limited time to a given process. In contrast, Non-Preemptive Scheduling is the scheduling technique in which the CPU is allocated to a process and hold by it till the process gets terminated. Read this article to learn more about Preemptive and Non-Preemptive Scheduling in Operating System and how they are different from each other. What is Preemptive Scheduling? Preemptive Scheduling is a type of CPU scheduling in which the resources (CPU Cycle) have been allocated to a process for a ... Read More

In this post, we will understand the difference between microkernel and monolithic kernel −MicrokernelIt is smaller in size.In this kernel, the services are kept in a separate address space.It executes slowly in comparison to monolithic kernel.It can be extended easily.If a service crashes, it effects the working of the microkernel.The code to build a microkernel is large.Examples of microkernel include: QNX, Symbian, L4Linux, Singularity, K42, Integrity, PikeOS, HURD, Minix, Mac OS X, and Coyotos.Monolithic KernelIn monolithic kernel, both user services and kernel services are kept in the same address space.Monolithic kernel is larger than microkernel.It executes quickly in comparison to ... Read More

An operating system acts as a bridge between the hardware and applications. The CPU is that part of the system which handles all the tasks of the system. Sometime such situations arise, when it is required to interrupt the currently running task and take a rapid action. Therefore, in operating system, there are two methods namely interrupt and polling for dealing with such events. In both interrupt and polling, the CPU is paused what it is doing and made to execute an essential task. Both interrupt and polling are quite different from each other in several ways. In this article, ... Read More