Real-Time operating system

In this article, we understand the real time operating system in detail.

What do you mean by Real-Time Operating System?

A real-time operating system (RTOS) is a special-purpose operating system used in computers that has strict time constraints for any job to be performed. It is employed mostly in those systems in which the results of the computations are used to influence a process while it is executing. Whenever an event external to the computer occurs, it is communicated to the computer with the help of some sensor used to monitor the event. The sensor produces the signal that is interpreted by the operating system as an interrupt. On receiving an interrupt, the operating system invokes a specific process or a set of processes to serve the interrupt.

This process is completely uninterrupted unless a higher priority interrupt occurs during its execution. Therefore, there must be a strict hierarchy of priority among the interrupts. The interrupt with the highest priority must be allowed to initiate the process , while lower priority interrupts should be kept in a buffer that will be handled later. Interrupt management is important in such an operating system.

Real-time operating systems employ special-purpose operating systems because conventional operating systems do not provide such performance.

The various examples of Real-time operating systems are:

• MTS
• Lynx
• QNX
• VxWorks etc.

Applications of Real-time operating system (RTOS):

RTOS is used in real-time applications that must work within specific deadlines. Following are the common areas of applications of Real-time operating systems are given below.

• Real-time running structures are used inside the Radar gadget.
• Real-time running structures are utilized in Missile guidance.
• Real-time running structures are utilized in on line inventory trading.
• Real-time running structures are used inside the cell phone switching gadget.
• Real-time running structures are utilized by Air site visitors to manipulate structures.
• Real-time running structures are used in Medical Imaging Systems.
• Real-time running structures are used inside the Fuel injection gadget.
• Real-time running structures are used inside the Traffic manipulate gadget.
• Real-time running structures are utilized in Autopilot travel simulators.

Types of Real-time operating system

Following are the three types of RTOS systems are:

Hard Real-Time operating system:

In Hard RTOS, all critical tasks must be completed within the specified time duration, i.e., within the given deadline. Not meeting the deadline would result in critical failures such as damage to equipment or even loss of human life.

For Example,

Let's take an example of airbags provided by carmakers along with a handle in the driver's seat. When the driver applies brakes at a particular instance, the airbags grow and prevent the driver's head from hitting the handle. Had there been some delay even of milliseconds, then it would have resulted in an accident.

Similarly, consider an on-stock trading software. If someone wants to sell a particular share, the system must ensure that command is performed within a given critical time. Otherwise, if the market falls abruptly, it may cause a huge loss to the trader.

Soft Real-Time operating system:

Soft RTOS accepts a few delays via the means of the Operating system. In this kind of RTOS, there may be a closing date assigned for a particular job, but a delay for a small amount of time is acceptable. So, cut off dates are treated softly via means of this kind of RTOS.

For Example,

This type of system is used in Online Transaction systems and Livestock price quotation Systems.

Firm Real-Time operating system:

In Firm RTOS additionally want to observe the deadlines. However, lacking a closing date might not have a massive effect, however may want to purposely undesired effects, like a massive discount within the fine of a product.

For Example, this system is used in various forms of Multimedia applications.

Advantages of Real-time operating system:

The benefits of real-time operating system are as follows-:

• Easy to layout, develop and execute real-time applications under the real-time operating system.
• The real-time working structures are extra compact, so those structures require much less memory space.
• In a Real-time operating system, the maximum utilization of devices and systems.
• Focus on running applications and less importance to applications that are in the queue.
• Since the size of programs is small, RTOS can also be embedded systems like in transport and others.
• These types of systems are error-free.
• Memory allocation is best managed in these types of systems.

Disadvantages of Real-time operating system:

The disadvantages of real-time operating systems are as follows-

• Real-time operating systems have complicated layout principles and are very costly to develop.
• Real-time operating systems are very complex and can consume critical CPU cycles.