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

The transport layer is essential for the source to deliver a complete message. The network layer is answerable for the end-to-end delivery of single packets.The transport layer obtains the messages of self-assertive length from the session layer, and divides them into packets. It also endures them to the network layer for communication, and completely reassembles the destination's packets.The transport layer data is an order number in every packet and helps the order numbers to identify the lost packets. Additionally, it ensures that the messages are regenerated in the proper order.The functioning of the transport layer is depicted in the diagram ... Read More

The network layer creates a logical association between the sender and the user by giving a logical way. This layer switches and routes the message packet as important to obtain them to their destination.It is responsible for sending and distributing the message packets. The network layer creates routing decisions and advances the packets for devices that are farther away than an individual connection.The network layer can also divide the huge packets into little chunks, if the packet is higher than the most extensive data link layer. The network reassembles the fragments into packets at the receiving end. Routers and Gateways ... Read More

The primary service of the data link layer is to support error-free transmission. The physical layer sends the information from the sender's hub to the receiver's hub as raw bits.The data link layer must identify and correct any bug in the communicated data.It takes packets from the network layer and divides the packets into frames which are shared by the sender through the physical layer, as demonstrated in the diagram below −A Cyclic Redundancy Check (CRC) which is inserted into the data frame can find the loss frames. Hence, the data link layer in the receiving device can request for ... 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