C# - Types

As mentioned earlier in the article, C# supports value types and reference types. Value types include simple data type such as int, char, and bool. Reference types include object, class, interface, and delegate. A value type contains the actual value of the object. That means the actual data is stored in the variable of a value type, whereas a reference type variable contains the reference to the actual data. Value Types Value types reference the actual data and declared by using their default constructors. The default constructor of these types returns a zero- initialized instance of the variable. The value types can further be categorized instance of the variable. The value types can further be categorized into many subcategories, described in the following sections.

Simple Types
Simple types include basic data types such as int, char, and bool. These types have a reserved keyword corresponding to one class of a CLS type defined in the System class.LEARN MORE>>>>

Operating System as a Resource Manager

The Operating system of a Computer works as an inerface between he user, and hardware devices. Applicaion software is designed to achieve specific tasks whereas the hardware helps in achieving the task. The compuer system provides all this with the use of available resources. The hard disk, primary memory and the processor can be though of as resources.

the Operating System provides an ordered and conrolled allocaion of the processor, memories and I/O devices among he various programs.

Take for example, a computer system with a printer and two applications programs running. If both programs wish to print a document at the same time, will those be printed by the printer or will there be a contention? Here, the operating system comes into play: it manages to queue the outputs to the printer. In short, this means that it is the ask of the operating system to manage a computer's resources. Some of the resources that the operating system manages are:

1. Processor
2. Memory
3. Devices
4. Information

To explain simply :-

• It manages the hardware and software resources of the system. In a desktop computer, these resources include such things as the processor, memory, disk space and more (On a cell phone, they include the keypad, the screen, the address book, the phone dialer, the battery and the network connection).
• It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.

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Types of Operating Systems

There are generally four types, categorized based on the types of computers they control and the sort of applications they support. The categories are:

1. Real-time operating system (RTOS) - Real-time operating systems are used to control machinery, scientific instruments and industrial systems. An RTOS typically has very little user-interface capability, and no end-user utilities, since the system will be a "sealed box" when delivered for use. A very important part of an RTOS is managing the resources of the computer so that a particular operation executes in precisely the same amount of time, every time it occurs.

2. Single-user, single task - As the name implies, this operating system is designed to manage the computer so that one user can effectively do one thing at a time. The Palm OS for Palm handheld computers is a good example of a modern single-user, single-task operating system.

3. Single-user, multi-tasking - This is the type of operating system most people use on their desktop and laptop computers today. Microsoft's Windows and Apple's MacOS platforms are both examples of operating systems that will let a single user have several programs in operation at the same time.

4. Multi-user - A multi-user operating system allows many different users to take advantage of the computer's resources simultaneously. Unix, VMS and mainframe operating systems, such as MVS, are examples of multi-user operating systems.

Types of Computers

Depending upon the way a system performs, a computer can be classified into the following types:

1. Digital

2. Analog

3. Hybrid

Digital Computers

It works with digits and numbers. For example, to calculate the distance travelled by a car, you might take into consideration the diameter of the tyre to calculate the circumference, the number of revolutions of the wheel per minute, the time taken in minutes, and then multiply them all to get the distance moved. This is known as digital calculation.

Digital computers can be classified on the basis of size and capabilities into :-

Super Computers

Mainframe Computers

Mini Computers

Micro computers

Personal Computes

Analog Computers

This computer  works on the principle of using continuous measurements of physical phenomenon like breath, rotation, electric effects, etc. Take the example of the principle of the milometer in a car. when the wheels of a car rotate, they make some gears to move. This movement is transmitted to the centre by a flexible shaft. The meter itself contains some gears/wheels marked with numerical numbers and is calibrated to calculate the exact distance travelled in metres or kilometres. In an analog computer, the input and output are continuously varying quantities such as voltage, instead of the discrete digits of digital computers.

Hybrid Computers

There are some computes which employ both digital as well as analog quantities. these are known as hybrid computers. For example, a digital thermometer employs a mechanism which converts the temperature observed into digital form using analog-to-digital conversion. Hybrid computers are the computers that are generally used in the process of control environment, where an analog (or continuously varying) input is provided to a computer which processes it digitally and presents the output in the analog or digital form as required.