Article Preview
Top1. Introduction
The operating system of a computer (Server) being highly secure depends on a number of technologies (tools & utilities) that working efficient and reliable manner in around the clock. The modern real time operating system provides access to a number of resources and sub-system, which are available to system software running on the system and to external devices like communication networks (LAN/WAN) (Kai, 2008) . The operating system is the most important and high available system software (program) that run on the heart of the computer (kernel). The every general-purpose computer must have an operating system to run other multiple application programs at the same time with multi location, function, operation and services without any fault (Reilly, 1995).
The operating system (server system) in large scale (MIMD) has even greater responsibilities and powers for large scale business like web based and mobile computing (Kai, 2008). It is just like a traffic management system, it makes sure that different programs and software packages the users and clients running at the same time do not interfere with each other. The operating system is also responsible for risk and security angle to ensuring that unauthorized users do not access the objects (Sun-Microsystems, 2002).
In the large scale operating system the multitasking, multiuser, time sharing operating system where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn. It manages the sharing of internal memory among multiple applications with multiple function and location. It handles input and output to and from attached hardware devices, such as hard disks, printers, and dial-up ports. On computers that can provide parallel processing, an operating system can manage how to divide the program (parallel program) so that it runs on more than one processor at a time (Kai, 2008; O’ Reilly, 1995).
The main components of the operating system are file, shell & kernel. The shell is communicated between the user, application, hardware and software. The file system is store the data, services and information as system software and application software (O’ Reilly, 1995). The sets of files system make the directory system. This directory space going to disk for storing and restoring purpose. This is called the hard disk of the computer system. The kernel improves the capabilities of processor, memory (Bernard, 2007). See Figures 1 and 2:
Figure 1. PMF protecting data and services
Figure 2. Internal architecture of RTOS
Associative Low: (P U M) U F = P U (M U F), (P ∩ M) ∩ F = P ∩ (M ∩ F)
Distributive Low: P U (M ∩ F) = (P U M) ∩ (P U F), P ∩ (M U F) = (P ∩ M) U (P ∩ F)