When an executable file is loaded into memory, it is called a process. A process is an instance of a program in executing. It contains its current activity, such as its program code and also the contents of the processor’s register. It generally includes the process stack, which contain temporary data, and a data section, which global variables. During runtime, it may include a heap, or dynamically allocated memory. In contrast with a program, a process is “an active entity, with a program counter specifying the next instruction to execute and a set of associated resources” (Operating System Concept 106). A process is a program that executes a single instance of a thread. Multiple threads can exist which allows more than one task to perform at a time. Multithreaded processes may share resources such as code, data, and file section. They do not share resources such as registers and stack.
According to Microsoft, the simplest definition of a process is an executed program. A thread is “the basic unit to which the operating system allocates processor time”. A thread can “execute any part of the process code, including parts currently being executed by another thread”. In Windows, threads share its virtual address space and system resources. Unlike the conceptual model, each thread “maintains exception handlers, a scheduling priority, thread local storage, a unique thread identifier and a set of structures the system will use to save the thread context until it is scheduled”. Like the conceptual model of a thread, Windows’ threads do not share registers and stack resources. This is because the thread context includes “the thread’s set of machine registers, the kernel stack, a thread environment lock and a user stack in the address sp...
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... to a session, a process group leader is “the process whose pid is the same as its process group ID”. On creation, a process becomes a member of its parent’s process group. A session contains a number of process groups. When a user logs out of the system, the kernel must be able to terminate all the processes it had running. Otherwise, the system will wait for inputs that will never come. To help with this task, processes are grouped into sessions. Every process group is in a unique session. On creation, a process becomes a member of its parent’s session. The session’s ID is “the same as the pid of the process that created the session through the setsid() system call” (Johnson and Troan). The session leader contains all of the process’ descendants unless the process is removed from the session. The setsid() returns the new session ID and does not take any arguments.
group or one person have control of a group of people. There is two different
3. Multi-threading occurs when multiple programs are processed at the same time or when several parts of a program are processed at the same time.
Processor (CPU) – The processor, also known as the Central Processing Unit runs the operating system and other applications. It is constantly receiving data from the user or other active software. The data is then processed and then an output is produced which either will be displayed on screen or stored by an application.
The processor is the factory floor of the computer; it’s recipient of all the instructions and then processes them. It conveys the instructions of a computer program by performing rudimentary arithmetical, logical, and input/output operations of the system.
Throughout history, man has been trying to explain man’s origin, purpose, and identity. By trying to figure out these difficult questions, many have come to the realization that either man is either theistic and believes there is a God and a supernatural presence or that man is atheistic believing that there is not God and rejects the supernatural. Because of this man can choose either of those world views. If they in fact choose the atheistic worldview they in turn will turn to another belief or set of values that reject the supernatural and replaces it with another aspect of life. One of those alternate philosophies would be process philosophy. Process philosophy is the belief that reality and life is not fixed or absolute meaning that everything within reality has the ability to change and progress as time continues on. Process philosophy has had a great effect on American society involving civil rights. Within the past century many changes have occurred including: voting and equal rights for blacks and women and rights for those who are homosexual. These rights are direct examples of process philosophy working to its fullest extent within American society.
To win an argument one must keep in mind the following factors: Is the argument
Virtualization technologies provide isolation of operating systems from hardware. This separation enables hardware resource sharing. With virtualization, a system pretends to be two or more of the same system [23]. Most modern operating systems contain a simplified system of virtualization. Each running process is able to act as if it is the only thing running. The CPUs and memory are virtualized. If a process tries to consume all of the CPU, a modern operating system will pre-empt it and allow others their fair share. Similarly, a running process typically has its own virtual address space that the operating system maps to physical memory to give the process the illusion that it is the only user of RAM.
The fundamental idea behind a virtual machine is to remove the hardware of a single computer and make it a self-contained operating environment that behaves as it is a separate computer. Essentially, the virtual machine is software that executes an application and isolates it from the actual operating system and hardware. CPU scheduling and virtual-memory techniques are used so that an operating system can create the illusion that a process has its own processor with its own (virtual) memory. The virtual machine provides the ability to share the same hardware yet run several different operating systems concurrently, as shown in Figure 2-11.
When executing (running), the compiler first parses (or analyzes) all of the language statements syntactically one after the other and then, in one or more successive stages or "passes", builds the output code, making sure that statements that refer to other statements are referred ...
...n extension as easy as possible for programmers to use (Denning, 1997). Virtual memory also makes better use of memory by loading in just a few pieces. This means at any one time, only a few pieces of any given process are in memory, therefore, more processes can be maintained in memory. For virtual memory to be realistic and effectual, two ingredients are needed. First, there must be hardware support for the paging and/or segmentation scheme to be employed. Second, the operating system must include software for managing the movement of pages and/or segments between secondary memory and main memory. Virtual memory combines your computer’s RAM with temporary space on your hard disk. When RAM runs low, virtual memory moves data from RAM to a space called a paging file. Moving data to and from the paging file frees up RAM so your computer can complete its work.
Reader and writer problem are examples of computer simultaneously there are three type of problem which handle many threads which are try to reach or access the resources at the same time in these threads some may able to read and some are writes with constraint no one process can access the recourses which is shared while it’s writing or reading and other process perform writing to it. Data structure of the writer and reader locks resolve the problem of reader and writer. Reader can only read data set and cannot update is done by the writer. And writer can both read and write.
Continuous process: production method which is similar to assembly line but the product flow continuously such as drugs, chemicals rather than discrete like cars. Facilities operated on continuous basis they may not shutdown (24 hours). There are some risks or wastes in these kind of production for example overproduction, waiting time, inventory and processing waste.
A computer is a combination of several parts. These parts are Random Access Memory (RAM), a Central Processing
Software, such as programming languages and operating systems, makes the details of the hardware architecture invisible to the user. For example, computers that use the C programming language or a UNIX operating system may appear the same from the user's viewpoint, although they use different hardware architectures. When a computer carries out an instruction, it proceeds through five steps. First, the control unit retrieves the instruction from memory—for example, an instruction to add two numbers. Second, the control unit decodes the instructions into electronic signals that control the computer.
Computer memory refers to any physical device that has the ability of storing information either permanently or temporarily. For instance, the Random Access Memory (RAM) is a volatile memory that has the ability of storing information on various integrated circuits that are used by not only the operating system, but also by the hardware and software. In essence, there are two major types of computer memory namely Read Only Memory (ROM) and the Random Access Memory (RAM). ROM refers to smallest parts of a computer system’s silicon or solid state memory which is not only fixed in size, but also permanently stores or keeps the instructions of the manufacturer upon switching on a computer. On the other hand, RM refers to the larger part of a computer memory that comprises of floppies, DVD, CD, and hard disk which are together referred to as secondary storage and which are employed or applied in both running of programs as well as archiving of relevant data. It is prudent to note that computer memory can either be volatile and non-volatile (Tanenbaum & Austin, 2012).