What do you mean by operating architecture?

What do you mean by operating architecture?

SYSTEM CALLS

System calls provide the interface between a process and the operating system.

· The purpose of system call is to request the operating system to perform some activity.

The execution of a system call require the user process to save its current state and pass the control of the CPU to the operating system to perform some function.

There are different system calls for performing different kinds of tasks:

1. FILE MANIPULATION SYSTEM CALLS, for example: open, close, read, write, reposition etc.

2. PROCESS CONTROL SYSTEM CALLS. For example : end, abort, load, execute, create process, terminate process, allocate and free memory, wait event, signal event.

3. DEVICE MANAGEMENT SYSTEM CALLS . for example: read write, reposition, request device, release device attributes, set device attributes etc.

4. INFORMATION MAINTENANCE SYSTEM CALLS. For example :get time or date, set time or date time or, get system data, set system data, get process attributes, file attributes, get device attributes etc.

5. COMMUNICATION SYSTEM CALLS. For example :send message, receive message, create communication connection, delete communication connection, transfer status information etc.

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Defination of OS(operating system) and its concepts

What do you mean by operating system? Definition : An operating system is a program that act as an interface between the user of a computer and the Computer hardware. Operating system is a first program that gets loaded into the memory through a process called booting. Concepts of operating system : · The purpose of operating system is to provide an environment in which a user can execute program in a convenient and efficient manner. · Operating system is an integrated set of program that manages the various hardware resources such as processor, memory, I/O Devices , communication devices and overall operation of a computer system. · Operating systems also acts as a platform on which various applications programs such as word processor and excel are executed. · The most common operating system are the window family of operating system (windows 98, window

Multi Level Queue Scheduling (MLQ)

Multi Level Queue Scheduling (MLQ) · Multilevel queue scheduling classifies the processes according to their types for example, a multilevel queue scheduling algorithm makes a common. · In this scheduling ready queue is divided into various queue that are called sub queues. A subqueue is a distinct operational queue · The process are permanently assigned to subqueues, generally based on some property of the process such as memory size,priority or process type · Each subqueue has its process sucheduling algorithm. For example interactive process at the foreground may use round robin scheduling while batch jobs at the background may use the FCFS method · For example, consider a system with four different queues 1. System processes 2. Interactive processes 3. End-user processes 4. Interactive processes · In this example, each queue has absolute priority absolute over low priority queues

Direct Communicationand Indirect communication

Direct Communication · Direct communication establishes a link between two processes. A communication link is a unidirectional path along which information flows. · two processes use single communication link to share information. · In this metod, there cannot be more that one link between two processes direct communication · Send and receive function used in direct communication are given below : · Send(process name , message ,(receive(process name , message) Send(A, message )- send a message to process A Receive(A, message )-receive a message from process B Indirect communication · In indirect communication , no direct communication link exists between two processes. · In this , messages are sent to and received from mailbox. · A mailbox is a specialized repository where message can be placed by processes and from

ENTERPROCESS COMMUNICATION AND SYNCHRONIZATION

ENTERPROCESS COMMUNICATION AND SYNCHRONIZATION · In multi programming environment multiple process co-exit . a single program may be broken into number of processes. · The process are classified into two categories : independent processes and cooperating processes. · An independent process is a standalone process that does not share any data with any other process. It cannot affect or be affected by the other processes executing in the system. In other words, the modification made to an independent process does not affect the functioning of other process. · A cooperating processes is a process that shares data with other processes in a system it can affect or be affectedly the other processes executing in the system · Cooperating processes can communicate in a shred memory environment . · The various reasons for using cooperating processes are: 1. Information sharing : when several users want to acce

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