Today we are familiar with the name of the computer. Computers already we can use in our daily lives in order to facilitate our work. It is certainly very much in line with the main purpose made computer. Besides the technological developments that occur at this time, take your computer to the next level. Surely it is not regardless of how the development of software and hardware of the computer itself. Surely we as computer users should menegetahui, how the existing structure on the computer. In addition we also need to know what services are provided by the computer to further facilitate our work. The process that is in it is also important for us to know. In this article, all these things will be explained,
Operating System Structure
The operating system is the software on the first layer is placed in the computer’s memory location. Other software besides the operating system to walk or run after the operating system is running. The operating system will henceforth provide services such as their access to disk, memory management, and user interface. In this first part we will discuss about the structure of the operating system. The structure of the operating system itself has to exist for no clear division of the tasks into specific components, so that it can run properly and according to its function.
The structure of the operating system itself consists of:
- The structure is simple
launched a number of systems on the market do not all have a good structure. Many operating systems are simple and have a lot of keterbatsan. There is a very limited operating system will be the hardware, so it is not divided into modules that exist.
- layered system
Basically the system is made by forming into a modular operating system. This is done by using a top-down approach in which all the functions are determined and divided into components.
The kernel is the central component of the operating system that regulates things such as service interruptions, divide the process into the processor, memory management, and so on. The kernel is the bridge between hardware and software. Microkernel exist for their ideas to implement features that needed it in the kernel.
Excess micro-kernel, which is a unified interface, it could add new features without recompilation, there are features that can be reduced and modified, and it is appropriate to develop an operating system-based object-oriented.
- virtual machine
The virtual machine is useful to give the illusion of multitasking. This machine can also isolate functionality and implementation enxtended multitasking machine, so it is easier to maintain.
This struktu implement operating system functions that can be part of the client (user process), for example, is a service request to the server process, access to hardware and so forth. The disadvantage is that this structure has slowed communication between client and server.
Operating System Services
The service provided by the operating system in general are provided to perform multiple commands to the running program.
There are several services on the operating system, namely:
- Ekesekusi program, the system can call the program for further processing and memory run
- Manipulation of the file system, which is the program’s ability to write, read, create, and delete files and
- Communication, ie when there is some process is being executed and terjaid exchange of information, the information exchange can be done by keeping the process within a single computer or a different computer, but in the same network.
- error detection, Which is an operating system can guarantee running correctly computing and DAPT detecting errors present on the CPU and memory, and I / O devices.
Process Operating System
A process is a program that is executed. The process can also be expressed as an activity that is going on. It should be stressed is not a process program. The process is the main concept of an operating system.
There are several elements of the process at the time of runnging, namely:
- Identifier, which is an identity for the process to distinguish from one another
- State, which is a condition of a process
- Priority, the priority of running a process to another process
- Program counter, the address of the next instruction to be executed
- Memory pointers, which is a pointer to the memory address of the program code and data related
- Context data, that the data contained in the register processor
- I / O information, which is information to request the I / O device that has not been met
- Accounting information, ie information about the amount of time the process has been used
Programs that are executed as well as the values or the information contained in the program counter, registers, and variables that exist at the time the program is run, where the operating system to control and manage what is happening in the computer system. Operating system to send and schedule the process to be executed by the processor and allocates resources to process and respond to requests for programs.
Thread Operating Systems
Thread is a basic unit of CPU utilization, which comprises a program counter, a register set, and stack. Threads share the code section, a data section, and operating system resources with other threads that are owned by the same process. Thread also called lightweight process. The difference between the single thread and multi-thread is a process with many threads that can do more than one task at the same time.
There are several threads status, namely
- Spawn, the thread can be formed by another thread in the process
- Block, which is a thread in the block when waiting for a process
- Unblock, that is, if the process is needed already exists, then the thread will be ready
- Finish, the thread has finished executing
The advantage of multi-threading, ie
- Responsive, namely to allow the program to continue even-even on the part of the diblock or are undergoing a lengthy operation.
- Distribution of resources, in general, divide thread of memory and resources of the process.
- Economical, which allocates memory and resources available.
Losses multi-threading, ie
- Multi-threading can disrupt the process with each other.
- The processing time of a single thread can not be increased, but otherwise can be derived.
- Necessary support from hardware and software to allow the use of multi-threading can be run.
We must also mengtahui, that there are several models of multi-threading, which is many-to-one, one-to-one and many-to, many.
Thread cancellation is the dismissal of the thread before the task is completed. Thread will be dismissed, also known as the target thread. Dismissal of threads dicancel can be done in two ways, namely asynchronous cancellation and cancellation defered. Asynchronous cancellation, which lay thrread instantly in a certain time. Defered cancellation, namely the target thread periodically check to see whether he should stop or not. This method allows the target thread to terminate itself.