Asked in Unix
What is kernel and shell in unix?
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Asked in Unix
Explain different layers of UNIX operating system Also explain interaction between shell and kernel using any suitable command?
Layers of UNIX Operation System along with an example to illustrate the interaction between shell and Kernel. The UNIX operating system is made up of three parts: the kernel, the shell and the programs. The kernel The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls. The shell The shell acts as an interface between the user and the kernel. The shell is a command line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The commands are themselves programs: when they terminate, the shell gives the user another prompt ($ on our systems). The programs A program is refereed to as a process while the kernel is running it. The Kernel can run the same shell program(or any other program) simultaneously for many users on a Unix System, and each running copy of the program is a separate process. The Shell is also a program that the UNIX Kernel runs for the user. As an illustration of the way that the shell and the kernel work together, suppose a user types rm myfile(which has the effect of removing the file myfile). The shell searches the filestore for the file containing the program rm, and then requests the kernel, through system calls, to execute the program rm on myfile. When the process rm myfile has finished running, the shell then returns the UNIX prompt $ to the user, indicating that it is waiting for further commands. - Submitted by SRK Student of NIIT Contact No. : +91-9534330837 Email: firstname.lastname@example.org
Asked in Unix
What is a shell in Unix?
Unix has two main sets internal implementation and the interface that is seen and used by users. i.e. Kernal and Shell. Kernal takes care of hardware interface and shell communicates with Kernal. Shell works as interpreter of user commands and translates them into action. The shell forms the outer part of the operating system and forms the interface between the user and the kernel. For each user logged in, there is shell in action. When a command is given by the user, it is examined by the shell and communicated to the kernel for execution. The functions used to communicate with the kernel are called system calls and are built into the kernel. The system calls are in all the flavors of UNIX are the same. Hence, software developed on one UNIX system can be easily run on another UNIX system. shell also has some internal commands, e.g. CD. External commands are saved in file system, when you enter such commands shell searches for them and runs them in new sub-process. application developed on unix communicates with shell and not kernal, this engables single application to be executed on various types of computer hardware without being modified
Asked in Unix
What are the four main components of UNIX Operating System?
Asked in Computer Programming, Linux, Unix
What is the name of kernel in Unix Linux and Windows Vista?
Asked in Windows XP, Unix
What is the architecture of Unix?
- The functioning of UNIX operating system is handled in three levels. At the heart of UNIX is the kernel, which interact with actual hardware. Kernel is the fundamental part(core) of the OS. That resides in main memory at all times. On the outer crust are the application packages and user programs. The dilled layer is the shell which acts as a mediator that translates the commands given by the application programs in the outer later and conveys them to the kernel layer. The kernel then executes these commands using the inner hardware.
Asked in Microsoft Windows, Unix
Where can you get a Unix shell for Windows?
Asked in Unix
What is a Unix 'default shell'?
The a default Unix shell is the shell that comes with and is activated initially with your distribution of Unix. The shell is essentially the program the runs the command line interface allowing someone to interact with their computer. Some examples are the Bourne-Again shell (bash) or the Bourne shell (sh).
What is difference between shell and kernel in Unix?
Shell is a program which allows the user to access the computer system. Shell is an interface between the user and computer system. Kernel is the only way through which the programs (all programs including shell) can access the hardware. Its a layer between the appliation programs and hardware. It is the core of most of the operating systems and manages everything including the communication between the hardware and software. KERNEL is the core part of operating system. It contain modules like device modules and other modules etc. Kernel is written in C language. Basically kernel is mediator between hardware and Operating System. But SHELL is an interface between users and operating system. Both are mediator but work is totally different. Let we have an example of "eject" command in Linux operating system: User give a command to Shell through input device like keyboard and see that command on video Device like monitor, but in actual concept is user give a command to shell, then this shell transfer that command to kernel.when kernel have module of that command then it transfer to hardware like CDROM. After that hardware behave as the module in kernel and then kernel again transfer the output to Shell. And finally shell transfer that output to user. Hardware <---> Kernel <---> Shell <---> User
Asked in Unix
Explain layered architecture of unix operating system?
)With a neat diagram explain different layer of Unix OS? Also explain interaction between Shell an kernel using any suitable commands. or Architecture of Unix. Ans- The part of UNIX that manages the hardware and the executing processes is called the kernel. The kernel is a collection of programs written in C which directly communicate with the hardware. Each hardware device is viewed as a file and is called a device file. This allows the same simple method of reading and writing files to be used to access each hardware device. The file system manages read and write access to user data and to devices, such as printers, attached to the system. It implements security controls to protect the safety and privacy of information. In executing processes the kernel allocates resources, including use of the CPU and mediates accesses to the hardware. The user commands are translated into action by the shell which acts as an interpreter. The shell forms the outer part of the operating system and forms the interface between the user and the kernel. For each user logged in, there is shell in action. When a command is given by the user, it is examined by the shell and communicated to the kernel for execution. The functions used to communicate with the kernel are called system calls and are built into the kernel. The system calls are in all the flavors of UNIX are the same. Hence, software developed on one UNIX system can be easily run on another UNIX system. UNIX's layered design insulates the application from the different types of hardware. This allows the software developer to support the single application on multiple hardware types with minimal effort. The application writer has lower development costs and a larger potential customer base. Users not only have more applications available, but can rely on being able to use the same applications on different computer hardware.