Real time systems are those systems that work within strict time constraints and provide a worst case time estimate for critical situations. Embedded systems provide a specific function in a much larger system. When there is an embedded component in a real time system, it is known as a real time embedded system.Types of Real Time Embedded SystemsThere are primarily two types of real time embedded systems i.e. hard and soft. An illustration to explain this further is −Hard Real Time Embedded SystemThis type of system makes sure that all critical processes are completed within the given time frame. This ... 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

There are two modes of operation in the operating system to make sure it works correctly. These are user mode and kernel mode.They are explained as follows −User ModeThe 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 the user mode. It is changed from 1 to 0 when switching from user mode to kernel mode.Kernel ... 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

In symmetric multiprocessing, multiple processors work in parallel and share resources like system bus and memory. It is a type of multiprocessing system and much more complex than asymmetric multiprocessing system.Symmetric Multiprocessing ArchitectureThe image depicting symmetric multiprocessing architecture is as follows −Some points explaining the above figure are −All the processors in the symmetric multiprocessing architecture contain a common bus and main memory. That is why symmetric multiprocessing is known as tightly coupled multiprocessing.Each of the processors in symmetric multiprocessing are equal and can execute different processes as required no matter where these processes are stored in memory. This is ... Read More

Storage Area Networks are typically used to provide access to data storage. These make sure that storage devices such as disks, tape drives etc. can be accessed by an operating system as system storage devices.Storage Area Networks are quite cheap and so are used both by large conglomerates and small businesses.An image that illustrates storage area networks is as follows −Components of Storage Area NetworksThe different components in storage area networks are −Host LayerAll the servers that provide access to the storage area network collectively constitute the host layer. These servers have host bus adapters that allow the operating system ... Read More

The hot standby mode is a fail-safe in which a hot standby component is part of an active system. If any component of the system fails, the hot standby component takes its place. In general, a hot standby can refer to any device, system etc. that overtakes operation from a failed device and reduces the startup delay that would otherwise be huge.A figure to further explain the hot standby mode is as follows −In general, it is expected that a system will have some failures. So, a hot standby is necessary to combat these failures.At the extreme, a hot standby ... Read More

Cache is a type of memory that is used to increase the speed of data access. Normally, the data required for any process resides in the main memory. However, it is transferred to the cache memory temporarily if it is used frequently enough. The process of storing and accessing data from a cache is known as caching.Uncached System vs Cached SystemA figure to better understand the difference between cached and uncached system is as follows −Some important points to explain the above figureare −In an uncached system, there is no cache memory. So, all the data required by the processor ... Read More