Found 2065 Articles for Operating System

The BIOS, operating system and hardware components of a computer system should all be working correctly for it to boot. If any of these elements fail, it leads to a failed boot sequence.System Boot ProcessThe following diagram demonstrates the steps involved in a system boot process −Here are the steps −The CPU initializes itself after the power in the computer is first turned on. This is done by triggering a series of clock ticks that are generated by the system clock.After this, the CPU looks for the system’s ROM BIOS to obtain the first instruction in the start-up program. This ... Read More

Loadable kernel modules in an operating system is an object file that contains code to extend the running kernel, which is also known as the base kernel. The loadable kernel modules are used to add support for file systems, hardware, system calls etc.A figure that shows the loadable modules of the operating system is as follows −Advantage of Loadable Kernel ModulesAn operating system would have to include all the systems that provided all anticipated functionalities in the base kernel if there were no loadable modules. This would lead to wastage of memory as most of those systems would not be ... Read More

A bootstrap program is the first code that is executed when the computer system is started. The entire operating system depends on the bootstrap program to work correctly as it loads the operating system.A figure that demonstrates the use of the bootstrap program is as follows −In the above image, the bootstrap program is a part of ROM which is the non-volatile memory. The operating system is loaded into the RAM by the bootstrap program after the start of the computer system. Then the operating system starts the device drivers.Bootstrapping ProcessThe bootstrapping process does not require any outside input to ... Read More

The Linux kernel modules can be loaded or removed from the kernel as required. This can be done without recompiling the kernel or rebooting the system and it enhances the functionality of the system.Without the kernel modules, the operating system would have to include all the systems that provide all anticipated functionalities in the base kernel. This would lead to wastage of memory as most of those systems would not be used often. Also, the users would need to rebuild and reboot the base kernel every time they would require a new functionality.The kernel modules have a .ko extension and ... Read More

The interface between a process and an operating system is provided by system calls. In general, system calls are available as assembly language instructions. They are also included in the manuals used by the assembly level programmers. System calls are usually made when a process in user mode requires access to a resource. Then it requests the kernel to provide the resource via a system call.A figure representing the execution of the system call is given as follows −As can be seen from this diagram, the processes execute normally in the user mode until a system call interrupts this. Then ... Read More

A command interpreter allows the user to interact with a program using commands in the form of text lines. It was frequently used until the 1970’s. However, in modern times many command interpreters are replaced by graphical user interfaces and menu-driven interfaces.Purpose of Command InterpretersCommand interpreters serve many purposes and are more useful than graphical user interfaces in some cases. Details about these cases are given as follows −Command interpreters have a large range of commands and queries available for different operations. Also, it is much faster to type than to click as is done using graphical user interfaces..There are ... Read More

Operating Systems have evolved over the years. So, their evolution through the years can be mapped using generations of operating systems. There are four generations of operating systems. These can be described as follows −The First Generation ( 1945 - 1955 ): Vacuum Tubes and PlugboardsDigital computers were not constructed until the second world war. Calculating engines with mechanical relays were built at that time. However, the mechanical relays were very slow and were later replaced with vacuum tubes. These machines were enormous but were still very slow.These early computers were designed, built and maintained by a single group of ... Read More

Many operating systems are not based on one model of the operating system. They may contain multiple operating systems that have different approaches to performance, security, usability needs etc. This is known as a hybrid operating system.The Hybrid operating system may allow one operating system to fulfil one set of requirements and the other operating system to fulfil the rest. For example, one of the operating systems may provide user interface, applications monitoring etc. while the other operating system may be a high-performance operating system that does not provide the same services as the first operating system.Features of Hybrid Operating ... Read More

Solaris is a Unix based operating system that was developed by Sun Microsystems and after its acquisition by Oracle, it is known as Oracle Solaris. It is known for its scalability and its innovative features such as DTrace, ZFS, Time Slider etc. Solaris is a microkernel design and it is not possible to create a monolithic Solaris kernel.A diagram demonstrating the structure of the Solaris operating system is as follows −The different components in the Solaris operating system structure are −HardwareThis includes the physical components of the computer system such as monitor, keyboard, data storage etc.I/O BufferI/O devices are very ... Read More

The interface between a process and an operating system is provided by system calls. In general, system calls are available as assembly language instructions. They are also included in the manuals used by the assembly level programmers.Unix System CallsSystem calls in Unix are used for file system control, process control, interprocess communication etc. Access to the Unix kernel is only available through these system calls. Generally, system calls are similar to function calls, the only difference is that they remove the control from the user process.There are around 80 system calls in the Unix interface currently. Details about some of ... Read More