1.Introduction to Operating system.
Definition.
• Operating system is a layer of system software that:
• Directly has advantage access to the underlying hardware.
• Hides the hardware complexity.
• Manage hardware on behalf of one or more applications according to some predefined policies.
• Operating system ensures that applications are isolated and protected from one another.
• Operating system works as a manager of resources are input and out devices, processor, files, memory, cpu etc and assign them to specific programs.
• That’s why operating system is resource manager. Figure 1.1
• Computing systems contains of a number of hardware components this include one or more processing
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• Overall operating system is responsible all types of resource allocations and resource management tasks on behalf of these applications. 2.Operating design principles.
Principle 1.
I. Separation of mechanism and policy.
Implement flexible mechanisms to support many principles.
Like least recently used(LRU), least frequently used(LFU) etc.
Principle 2.
II. Optimize for common case.
• Where will the operating system be used?
• What will the user want to execute on that machine?
• What are the workload requirements? so we need to understand the common case. On the base of that common case pick a specific policy that make sense and that can be supported given the underlying mechanisms that the operating system support.
Figure 2.1
3.Types of operating systems.
There are the following types of operating systems which are mostly common used.
I. Batch operating
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It is also called multitasking. It is a logical extension of multiprogramming. In time sharing operating system minimum processors are used and minimum response time.
Advantages of Time sharing operating system.
I. Prevent duplication of software.
II. Increase performance.
III. Reduces CPU lazy time.
Disadvantages of Time sharing operating system.
I. Problem of dependability or trusty.
II. Problem of data communication.
III. Asking for answer of security of user programs and data.
3.Distributed operating system.
Distributed systems used various processors to serve various real time applications and various users.
The processors interact with one another by multiple communication lines, such as telephone lines. It is called distributed systems. Advantages of Distributed operating system.
I. Effective service for users.
II. Prevent of delay in data processing.
III. Reduce load on host machine.
4. Network operating system.
A Network operating system build to carry workstation, personal computer to allow share file through connected on a local area network(LAN).
Example.
Unix
Linux
Mac operating system
1. A device is a computer if it has an input device, central processing unit (CPU), internal memory, storage, and an output device.
It is the operating system’s job to ensure that enough of the processor’s time have been allocated for each application or process that the user is trying to execute. Notably important for multitasking and for a smooth general usage. When the operating system wants to execute a program, it first has to locate the files in the storage drive, load the information towards the main memory and then instruct the central processing unit to begin executing the application from the beginning. • Memory storage and management. The operating system has to ensure that for each process there is enough memory to permit proper functioning, as well as making sure that one task does not use the memory that was allocated towards a different process.
Not long ago computers were non-existent in many homes. When computers were first introduced to the world, they were for the sole purpose of performing business functions. The only people who owned computers were large organizations. Eventually, computers were introduced into the homes of those who could afford to buy them. Today, just about everyone owns some form of system that they use daily to help manage their day-to-day operations. What many once survived without now seems impossible to do without. As technology continues to grow, it has a greater effect on families and the education system. Some companies such as Microsoft and Apple made it possible to reinvent a new form of technology that would change the world. Each company had some form of struggle and overtime had to keep up with the changes of time and the way people communicated. From the first day of its invention, organizations have had to steadily implement new operating systems to keep up with the demands of the people while staying afloat with competitors. The ways of life for many have changed as well as the way people communicate. It is evident that the history and uses of computers have changed the world but these computers could not perform without the operating systems. Various operating systems will be discussed, how they began and how they each changed since they were first introduced. Although, they all had a purpose each varied in how they performed and changed the lives of many and will continue in the near future.
Through this evolution the kernel and associated software were extended until a complete operating system was written on top of the kernel in the language C. UNIX APPLICATION PROGRAMMING INTERFACE Many proprietary operating systems have a simplified view of application behavior. The typical application reads some data from disk, tape or a terminal and does some processing. Output is produced onto disk, tape, tape, terminal, or printer. The operating systems generally provide easy to use well-implemented facilities to support these types of facilities. As applications become more sophisticated they need new features such as network access, multi-tasking, and interprocess communications.
However in both systems, the hardware cannot multitask without the software, which enables the OS to be used and updated. Kernel code is responsible to manage the work in both hardware and software for the OS, and it also transmits the information using the Input and Output system in OS X and it does a similar function in Windows10, but it is called device manager.
Multiprocessor. SMP support is available on the Intel and SPARC platforms (with work currently in progress on other platforms), and Linux is used in several loosely-coupled MP applications, including Beowulf systems and the Fujitsu AP1000+ SPARC-based supercomputer.
The CPU (Central Processing Unit) is the brain of the system. It executes all the program code from the operating system and the applications you run, and does most of the calculating and processing of data. It sends commands to direct the actions of all the other components in the PC and it manages the distribution of data to/from those various components.
Any program is only as good as it is useful- Linus Torvalds. According to Merriam-Webster dictionary an operating system is the main program in a computer that controls the way the computer works and makes it possible for other programs to function. Linus Torvalds in 1991 arranged the UNIX operating system to be used in the stead of ms-dos; Windows 95 was ran on top ms-dos. Windows and Linux are different operating systems built off different systems of code making security, stability, usability, and the communities comparatively different.
Operating system design goals and requirements are divided into two groups. What are these two groups?
Local Area Networks also called LANs have been a major player in industrialization of computers. In the past 20 or so years the worlds industry has be invaded with new computer technology. It has made such an impact on the way we do business that it has become essential with an ever-growing need for improvement. LANs give an employer the ability to share information between computers with a simple relatively inexpensive system of network cards and software. It also lets the user or users share hardware such as Printers and scanners. The speed of access between the computers is lighting fast because the data has a short distance to cover. In most cases a LAN only occupies one or a group of buildings located next to each other. For larger area need there are several other types of networks such as the Internet.
Smartphone’s, PADs, tablet computers and other handheld devices that are used to run over operating system are called mobile operating system (Mobile OS). A specified data and programs that run over the mobile devices are referred as mobile operating system. It handles all the hardware and optimizes the performance of the application software in the device. Mobile multimedia functions, Internet connectivity and many other applications are handled by mobile operating system. Base infrastructure software inherent of a computerized system is operating system. It controls all primitive operations of the computer such as PDA and Smartphone. To install and execute the third party applications (known as apps) by users are allowed in the operating system devices. It enumerates new functionalities of the devices. Today mobile devices with a desired OS are called Smartphone’s and a wide range of applications for instances games, apps,communication or social media apps, digital maps, etc are used by users.
An Operating system is system software that controls the system’s hardware that interacts with users and the application software. As we all may know, Windows Microsoft has always been a commercial high-level sale in the retail industry and an in domain operating system used today. But there are more operating systems than just Windows Microsoft than the general population may assume. Linux is another well-known operating systems, which is free and open-source software. Linux is also used in companies we would have never thought of like Google, NASA, USPS, Amazon and many more companies. Linux and Microsoft operating systems have been in competition to see which one is the best operating system in the market. There are so many resemblances
systems are able to run for the most part by themselves. For this paper, I will be discussing
Computers are very complex and have many different uses. This makes for a very complex system of parts that work together to do what the user wants from the computer. The purpose of this paper is to explain a few main components of the computer. The components covered are going to be system units, Motherboards, Central Processing Units, and Memory. Many people are not familiar with these terms and their meaning. These components are commonly mistaken for one and other.
In designing a computer system, architects consider five major elements that make up the system's hardware: the arithmetic/logic unit, control unit, memory, input, and output. The arithmetic/logic unit performs arithmetic and compares numerical values. The control unit directs the operation of the computer by taking the user instructions and transforming them into electrical signals that the computer's circuitry can understand. The combination of the arithmetic/logic unit and the control unit is called the central processing unit (CPU). The memory stores instructions and data.