The 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.An image that shows the loadable modules of the operating system is as follows −The different types of kernels in the operating system that may require loadable kernel modules are −MicrokernelA microkernel is the minimum software that is required to correctly implement an operating system. This includes memory, process scheduling mechanisms and basic inter-process communication.The microkernel contains ... Read More

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

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

iOSThe iOS is the operating system created by Apple Inc. for mobile devices. The iOS is used in many of the mobile devices for Apple such as iPhone, iPod, iPad etc. The iOS is used a lot and only lags behind Android in terms of popularity.The iOS architecture is layered. It contains an intermediate layer between the applications and the hardware so they do not communicate directly. The lower layers in iOS provide the basic services and the higher layers provide the user interface and sophisticated graphics.The layered architecture of iOS is given as follows −AndroidAndroid is an operating system ... Read More

The GRUB (Grand Unified Bootloader) is a bootloader available from the GNU project. A bootloader is very important as it is impossible to start an operating system without it. It is the first program which starts when the program is switched on. The bootloader transfers the control to the operating system kernel. GRUB Features GRUB is the default bootloader for many of the Linux distributions. This is because it is better than many of the previous versions of the bootloaders. Some of its features are: GRUB supports LBA (Logical Block Addressing Mode) which puts the addressing conversion used ... Read More

The Erasable Programmable Read Only Memory is a memory chip that does not lose data even when the power is switched off. This is a non-volatile memory type i.e. it retains data even when the power is switched off. Each EPROM is individually programmed by an electronic device. After that, the data can be erased by exposing the EPROM to strong ultraviolet light.An EPROM contains a transparent fused quartz window at the top of the package which allows exposure to ultraviolet light. The silicon chip is visible from this window.EPROM OperationA single field effect transistor constitutes a storage location. This ... Read More