Threads in Operating System

In traditional operating systems, each process address space and the single thread of control. In fact, it is almost the definition of the process. However, often there are cases where it is desirable to control the various strands of the same address space running in quasi-parallel as if they are separate processes. except that was shared address space. In this excerpt from his book, Modern Operating Systems, Andrew Tanenbaum said these cases and their consequences.

Despite the large thread in the process execution, process and issues related to other concepts. Processes are pooling resources and sharing issues are the entities that received run on the CPU. Thread is a single sequence stream within a process. As the discussion of some of the characteristics of the process, they are sometimes called lightweight processes. In this case, different threads of execution flows. Given the many threads that are popular methods to improve application concurrency.

The CPU goes back and forth quickly between threads and the illusion that the threads can run simultaneously. As an example of the traditional methods of process by a thread, the thread in one of several states (running, blocked, or ready-ready) to be. Each thread has its own stack. Since the wire will usually call for different methods and therefore a different version of the story. Therefore, you must own thread stack. The operating system is the portion of the wire, the basic unit of CPU use wire. A wire or from a program counter (PC), a set of registers and stack memory. Materials are not independent of other processes, such as the son of the results with other threads that code section, data section, the operating system resources known shared tasks such as file and open signs.

€ The unit is essentially the use of CPU threads, which means it runs a production process – is the deal. Thus, each process has at least one thread (thread).

€ This means we now have a shared set of metadata and the process of discussion:

1. The address space of the process, manages global variables, or more specific, such as open files, child processes if any, and signals and signal handlers do not care if some knowledge of accounting.

2. In Tools, on the wire by hand, others, and his stack, registers, variables and the current execution state. This is part of the control blocks of the Tools.

€ Some advantages of a child through the process: lightness it takes less time to create and destroy, are emerging in the context of a more rapid, which share memory and files without calling kernel system calls.

€ There are two main drivers of threads:

1. Kernel threads in Windows child, child provided by the kernel, making control of kernel programming heavier, but it’s the only way a process can be performed on two different processors, for example.

2. The user-level threads or Windows application tools fiber son to run the application and lack many benefits, such as the fact that once their blocks, they are all blocked. On the other hand, the kernel does not handle them, and then we are free to do whatever we want. Coroutines applications using threads in general manage their time.

Load Windows XP Operating System Properly By Fixing Windows XP Bootloader

Do you have any idea what the Windows XP bootloader is? Well it is an important and informative file instructing the computer on loading the Windows XP operating system. If there are any viruses in your system, then the virus has the capacity to either corrupt or completely damage the boot-loader file. If this happens, your operating system will not be able to boot up or it may so happen that Windows XP may boot up partially. It is not a big deal to get the operating system fixed; if you are not confident in doing the job on your own, get a computer help service to do the work for you.

The user will need the original CD for Windows XP installation or may be an XP recovery disc. The user has to get started inserting the recovery disc or the installation CD in the computer and restarting the machine. The system may ask you to boot form the CD itself, instead of trying to boot the operating system in the normal manner. You have to hit any key when you are prompted to do so and then wait for sometime till the setup program loads completely. If there are any problems, contact an online computer repair service for assistance.

At the next step you have to hit the R key available on the Welcome to Setup screen. Once you are done with this, the CD will get the Recovery Console launched instead of making efforts in installing the Windows XP operating system in your computer. Note that if the user has an administrator password on the copy of Windows XP, then that password has to be entered while logging in to the Recovery Console. In case of any problems, do not hesitate to get in touch with a remote tech support provider as soon as possible.

Your next job in repairing the Windows XP boot-loader issues will be to select the installation for the operating system that you want to fix. Normally there is only one option that you must choose. Now you must wait for some time before the command prompt appears and then type in fixmbr. Wait for being prompted, and then proceed to press the y key on the keyboard. This will enable the FixMBR utility to overwrite the bootloader that was corrupted or damaged with a fresh copy.

Now get the XP disc or the recovery disc removed from the computer system and type in the command prompt exit. The exit command is the one that makes the computer reboot; it permits the machine to load the new boot-loader file that has been used to overwrite the bootloader file that was corrupted. Now the Windows XP users can startup the machine as it is done normally. There should be no more problems in Windows XP booting properly.

If you have gone wrong somewhere and your system still cannot get the operating system loaded for you to use, do not waste time and contact a PC repair service.

Batch Operating System and Timesharing Operating System

Batch Operating System:

In early computer systems, the user did not interact directly with the computer system. The data and programs were first prepared on the input media such as punched cards or punched tape. The data and programs prepared on the punched tape or punched cards were referred to as jobs. These jobs were submitted to the computer operator. The computer operator would arrange the jobs into proper sequence known as batches and run the batches through the computer. The batch operating system was used to manage and control such type of operations.

The simple batch operating system transfers the jobs to the processor one by one. When one job is completed, then control is transferred to next job. For example, if first job is about to print a document on printer and second job is to execute a program for creating and editing text document. In this case, when first job is completed only then the second job is started.

The first batch operating system was developed in the mid-1950s by General Motors for IBM 701 computers. This system was revised and then implemented on the IBM 704 computers. By the early 1960s, a number of vendors had developed batch processing systems for their computers but the most popular batch operating system was “IBSYS” of IBM. This operating system was developed for the IBM 7090 / 7094 computers.

Timesharing Operating System:

Timesharing system is a multiprogramming, multiprocessing and interactive system. It allows multiple users to share the computer at the same time. This system executes multiple jobs of users by switching among them. Timesharing is used when multiple users are connected to a single computer in a communication network. Each user accesses the computer with its own terminal.

Timesharing operating system uses the CPU scheduling. Each user is assigned a small time unit known as time slice. The job of a user executes within its time slice. When the allocated time period for a job is used, the next job is allocated to it. This process continues in a cycle. Thus at a regular time intervals, some users may logout from the system, while new users may login into the system.

The processor switches so rapidly from one user to the next and each user feels that the entire computer system is dedicated to his use. So the users can interact with their programs, while they are running.

In timesharing system (like multiprogramming system), multiple jobs are also simultaneously loaded in main memory. The main memory cannot accommodate all these jobs at the same time. In this case, the jobs are kept on the disk in the job pool. The jobs in job pool await allocation of main memory. If several jobs are ready to be brought into memory, and if there is not enough room for all of them, then the system must require memory management. Similarly, if many jobs are ready to run at the same time, the system must schedule these jobs. The time-sharing systems must also provide a file system management to manage the input and output data of the multiple users.

Timesharing system (and multiprogramming system) also creates challenges for the operating system. If there are multiple jobs in memory, then they must be protected from interfering with each other such as modifying each other’s data.

One of the first timesharing operating system was the Compatible Time-Sharing System (CTSS). This operating system was first developed for the IBM 709 in 1961 and later transferred to IBM 7094. Nowadays examples of important timesharing operating systems are UNIX, Linux, Windows NT Server and Windows 2000 Server.