Kernel

Pinning kernel memory and the kernel stack for applications with real-time requirements can provide performance improvements by ensuring that the kernel memory and kernel stack for an application is not paged out.

Asynchronous IPC requires that the kernel maintains buffers and queues for messages, and deals with buffer overflows; it also requires double copying of messages (sender to kernel and kernel to receiver).

Originally, the patches that make up SELinux had to be explicitly applied to the Linux kernel source; SELinux has been merged into the Linux kernel mainline in the 2.6 series of the Linux kernel.

Last month's new version of the Linux kernel, 6.12, has been confirmed as the newest LTS release… which also marks the end of the line for kernel 4.19.

AIX 7.2 principal feature is the Live Kernel Update capability which allows OS fixes to replace the entire AIX kernel with no impact to applications.

Before Linux 2.6.33, citation ReiserFS heavily used the big kernel lock (BKL) a global kernel-wide lock which does not scale very well citation.

By default, AIX V7.1 pins kernel memory and includes support to allow applications to pin their kernel stack.

Exceptions to this are programs that contain direct calls to AIX kernel based APIs as there is no AIX kernel in PASE.

If a program wishes to access hardware, for example, it may interrupt the operating system's kernel, which causes control to be passed back to the kernel.

In a traditional kernel extensive work needs to be carried out to make it reentrant or interruptible, as programs running on different processors could call into the kernel at the same time.

In contrast, the security of a "modified" system (based on an SELinux kernel) depends primarily on the correctness of the kernel and its security-policy configuration.

In general, "M:N" threading systems are more complex to implement than either kernel or user threads, because changes to both kernel and user-space code are required.

In this article the term "thread" (without kernel or user qualifier) defaults to referring to kernel threads.

In this model, when control is passed to a program by the kernel, it may execute for as long as it wants before explicitly returning control to the kernel.

Kernel-mode dumps main There are three types of kernel-mode dumps: * Complete memory dump contains full physical memory for the target system.

Kernel modules Kernel - Contains Task switch, Memory allocation, and most non-I/O calls IOMAN - Handles I/O calls to various File Managers and drivers.

Models 1:1 (kernel-level threading) Threads created by the user in a 1:1 correspondence with schedulable entities in the kernel citation are the simplest possible threading implementation.

N:1 (user-level threading) An N:1 model implies that all application-level threads map to one kernel-level scheduled entity; the kernel has no knowledge of the application threads.

Some threading implementations are called kernel threads, whereas light-weight processes (LWP) are a specific type of kernel thread that share the same state and information.

SunOS 4.1.2 introduced support for Sun's first sun4m -architecture multiprocessor machines (the SPARCserver 600MP series); since it had only a single lock for the kernel, only one CPU at a time could execute in the kernel.