In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, thread management, and inter-process communication (IPC).
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
A real-time operating system (RTOS) is an operating system (OS) intended to serve real-time applications that process data as it comes in, typically without buffer delays. Processing time requirements are measured in tenths of seconds or shorter increments of time. A real-time system is a time-bound system which has well-defined, fixed time constraints. Processing must be done within the defined constraints or the system will fail. They either are event-driven or time-sharing. Event-driven systems switch between tasks based on their priorities, while time-sharing systems switch the task based on clock interrupts. Most RTOSs use a pre-emptive scheduling algorithm.
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems, but in most cases a thread is a component of a process. Multiple threads can exist within one process, executing concurrently and sharing resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its executable code and the values of its dynamically allocated variables and non-thread-local global variables at any given time.
QNX is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. QNX was one of the first commercially successful microkernel operating systems. As of 2020, it is used in a variety of devices including cars and mobile phones.
Exokernel is an operating system kernel developed by the MIT Parallel and Distributed Operating Systems group, and also a class of similar operating systems.
In computing, scheduling is the method by which work is assigned to resources that complete the work. The work may be virtual computation elements such as threads, processes or data flows, which are in turn scheduled onto hardware resources such as processors, network links or expansion cards.
Micro-Controller Operating Systems is a real-time operating system (RTOS) designed Jean J. Labrosse in 1991. It is a priority-based preemptive real-time kernel for microprocessors, written mostly in the programming language C. It is intended for use in embedded systems.
The architecture of Windows NT, a line of operating systems produced and sold by Microsoft, is a layered design that consists of two main components, user mode and kernel mode. It is a preemptive, reentrant multitasking operating system, which has been designed to work with uniprocessor and symmetrical multiprocessor (SMP)-based computers. To process input/output (I/O) requests, they use packet-driven I/O, which utilizes I/O request packets (IRPs) and asynchronous I/O. Starting with Windows XP, Microsoft began making 64-bit versions of Windows available; before this, there were only 32-bit versions of these operating systems.
Vanguard is a discontinued experimental microkernel developed at Apple Computer, in the research-oriented Apple Advanced Technology Group (ATG) in the early 1990s. Based on the V-System, Vanguard introduced standardized object identifiers and a unique message chaining system for improved performance. Vanguard was not used in any of Apple's commercial products. Development ended in 1993 when Ross Finlayson, the project's main investigator, left Apple.
In computing, preemption is the act of temporarily interrupting an executing task, with the intention of resuming it at a later time. This interrupt is done by an external scheduler with no assistance or cooperation from the task. This preemptive scheduler usually run in the most privileged protection ring, meaning that interruption and resuming are considered highly secure actions. Such a change in the currently executing task of a processor is known as context switching.
In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults and malicious behavior. This approach is diametrically opposite to that of capability-based security.
Linux startup process is the multi-stage initialization process performed during booting a Linux installation. It is in many ways similar to the BSD and other Unix-style boot processes, from which it derives.
A process is a program in execution. An integral part of any modern-day operating system (OS). The OS must allocate resources to processes, enable processes to share and exchange information, protect the resources of each process from other processes and enable synchronization among processes. To meet these requirements, the OS must maintain a data structure for each process, which describes the state and resource ownership of that process, and which enables the OS to exert control over each process.
The kernel is a computer program at the core of a computer's operating system that has complete control over everything in the system. It is the "portion of the operating system code that is always resident in memory", and facilitates interactions between hardware and software components. On most systems, the kernel is one of the first programs loaded on startup. It handles the rest of startup as well as memory, peripherals, and input/output (I/O) requests from software, translating them into data-processing instructions for the central processing unit.
Verve is a research operating system developed by Microsoft Research. Verve is verified end-to-end for type safety and memory safety.
eXtremeDB is a high performance, low-latency, ACID-compliant embedded database management system using an in-memory database system (IMDS) architecture and designed to be linked into C/C++ based programs. It works on Windows, Linux, and other real-time and embedded operating systems. Building on this core IMDS, there are several editions supporting high availability, database clustering, hybrid data storage, columnar layout of time series data and other specialized abilities.
Compute Node Kernel (CNK) is the node level operating system for the IBM Blue Gene series of supercomputers.
OpenTag is a DASH7 protocol stack and minimal Real-Time Operating System (RTOS), written in the C programming language. It is designed to run on microcontrollers or radio Systems on a Chip (SoC). OpenTag was engineered to be a very compact software package. However, with proper configuration, it can also run in any POSIX environment. OpenTag can also provide all functionality required for any type of DASH7 Mode 2 device, rather than just the eponymous “tag”-type endpoint device.
