OPERATING SYSTEM (LINUX)

Operating System (Linux)



Abstract

In general, the Linux scheduler can ensure fairness and provide excellent interactive performance at the same time. However, our experiments Linux and mathematical analysis have shown that the current term interactivity mechanism tends to incorrectly categorize non-interactive network applications as interactive, which can lead to serious fairness or starvation issues. In the extreme, a single process can unjustifiably obtain up to 95% of the CPU. Network packets arrive at the receiver independently and discretely, and the “relatively fast” non-interactive network process might frequently sleep to wait for packet arrival. Though each sleep lasts for a very short period of time, the wait-for-packet sleeps occur so frequently that they lead to interactive status for the process.

Operating System (Linux)

Introduction

Linux is a UNIX-like operating system that is largely (and increasingly) POSIX-compliant. It was first written by Linus Torvalds (see The Rampantly Unofficial Linus Torvalds FAQ), who started in 1991 with the idea of learning the capabilities of an 80386 processor for task switching. Originally named Freax, it was originally hosted using the Minix operating system.

The assumptions for Linux have changed slightly since then; portability now is a goal, and it is certainly not simply an "academic" requirement for software. It notably moved up on the priority list when Digital Equipment Corporation (now a Compaq company ) gave Linus an Alpha-based system; today there are commercial enterprises actively selling and supporting products based on the various ports to IA-32, PowerPC, MIPS , Alpha, and ARM architectures.(Josh, 2005)

Device management

By providing a mechanism for device drivers to register device nodes, it is possible to send notifications to user space when these registrations and un-registrations occur. This allows more sophisticated device management schemes and policies to be implemented. Furthermore, a virtual _le-system mounted onto /dev opens the possibility of capturing le-system events and notifying user-space. For example, opening a device node, or attempting to access a nonexistent device node, can be used to trigger a specific action in user pace. This further enhances the level of sophistication possible in device management.

Device implements a simple yet powerful protocol for communication with a device management daemon which runs in user-space. It is possible to send a message to on any event, such as registration/un-registration of device entries, opening and closing devices, looking up inodes, scanning directories and more. This opens many possibilities for more advanced device management. The daemon may be congaed to take a variety of actions for any event type. (Etsion, 2004)

Resource management

SLURM is an open-source resource manager designed for Linux clusters of all sizes. It provides three key functions. First it allocates exclusive and/or non-exclusive access to resources (computer nodes) to users for some duration of time so they can perform work. Second, it provides a framework for starting, executing, and monitoring work on a set of allocated nodes. Finally, it arbitrates contention for resources by managing a queue of pending work. Resource management is unique in several respects:

Its source code is freely available under the GNU General Public ...