Introduction to advanced OS

7/31/2019 Introduction to advanced OS

1/27

Advanced Operating Systems

PG-CSE1-02AGENDA

NEED FOR ADVANCED OS

OVERVIEW OF TYPES OF ADVANCED OPERATING

SYSTEMS

REVIEW OF PROCESS SYNCHRONIZATION

Dr.Manali Kshirsagar,YCCE,Nagpur


2/27


Traditional OS ran on stand-alone computers

with single processors.

Considerable advances in Integrated Circuit andcomputer communication technologies led to

unprecedented interest in multicomputer systems



3/27


Variety of computer architectures ranging from

shared memory multiprocessors to distributed

memory distributed systems were introduced.These multicomputer systems were prompted by

the need for high-speed computing that

conventional single processor systems wereunable to provide.



4/27


The design of operating systems for these

multiprocessor and distributed systems becomes

very complex and difficult since there are manyidiosyncrasies associated with these systems

which are not present in traditional single

processor systems.



5/27


Due to their relative newness and enormous

design complexity, operating systems for thesemulticomputers are referred to as Advanced or

Modern operating systems.



6/27


An advanced operating system not only

harnesses the power of a multicomputer system

but also provides a high level coherent view ofthe system.

Due to advanced OS, a user views a

multicomputer system as a single monolithicpowerful machine.



7/27


TYPES OF ADVANCED OPERATING SYSTEMS

Advanced operating systems

Architecture driven Application driven

Distributed OS Multiprocessor OS Database OS Real-time OS



8/27


The design of advanced operating systems has

been driven by the following factors :

Advances in the architecture of multicomputersystems, evolution of wide variety of high-speed

architectures.

Examples are multiprocessor systems anddistributed computing systems.



9/27


Several important applications namely database

systems, real time systems , graphics systems,

surveillance, process control etc. require specialoperating system support for efficiency which

cannot be provided by general purpose OS.



10/27

Distributed Operating Systems

Distributed OS are the OS for a network of

autonomous computers connected by a

communication network



11/27

Distributed Operating Systems

Distributed OS controls and manages the

hardware and software resources of distributed

system and provides the view of the entire systemas a monolithic computer system

When a program is executed in a distributed

system, the user is not aware of where theprogram is executed or of the location of the

resources accessed



12/27

Basic design issues of a distributed OS

Process synchronization

Deadlocks

Scheduling

File Systems

Inter process communication

Memory and buffer management

Failure recovery etc.



13/27

Idiosyncrasies of a distributed systems

Lack of both shared memory and a physical

global clock

Unpredictable communication delays



14/27

Multiprocessor Operating Systems

A multiprocessor system consists of a set of

processors that share a set of physical memory

blocks over an interconnection networkThus, it is a tightly coupled system where

processors share an address space



15/27

Multiprocessor Operating Systems

A multiprocessor OS controls and manages the

hardware and software resources such that users

view the entire system as a powerful uniprocessorsystem

A user is not aware of the presence of multiple

processors and the interconnection network



16/27

Basic design issues of a Multiprocessor

OS

Same as in a traditional operating system



17/27

Idiosyncrasies of a multiprocessor system

The issues of process synchronization , task

scheduling, memory management and protection

and security become more complex because themain memory is shared by many physical

processors



18/27

Database Operating Systems

A database operating system must support :

the concept of transaction

operations to store, retrieve and manipulate alarge volume of data efficiently

primitives for concurrency control

system failure recovery

buffer management scheme for storingtemporary data and data retrieved fromsecondary storage



19/27

Idiosyncrasies of a database operating system

Concurrency control is the most challenging

problem in the design of the database operatingsystem



20/27

Real-time Operating Systems

Jobs have completion deadlines in RTOS

A job should be completed before its deadline to

be of use(in soft real-time systems)

Or to avert a disaster (in hard real time systems)



21/27

Idiosyncrasies of a real-time operating

system

The major issue in the design of real time

operating systems is the scheduling of jobs in sucha way that a maximum number of jobs satisfy

their deadlines

The other issues include designing languages andprimitives to effectively prepare and execute a job

schedule



22/27

OVERVIEW OF PROCESS SYNCHRONIZATION

MECHANISMS

Process a program in execution means a programwhose execution has started but is yet not

complete

Basic states of a process running, ready, blocked

Running processor is executing the instructions of

the corresponding process



23/27


MECHANISMS

Ready- the process is ready to be executed, but

processor is not available for the execution of this

process

Blocked the process is waiting for an event to

occur e.g. I/O operation waiting to be completed,

memory to be made available, a message to bereceived etc.



24/27


MECHANISMS

A data structure called as PCB stores completeinformation about a process such as its ID, process

state, priority, privileges, virtual memory address

translation maps etc.Operations such as create, kill, signal, suspend,

schedule, change-priority, resume etc . can be

performed on process



25/27

Types of processes

Independent

Cooperating

Process synchronization is required when

processes interact with each other

Process synchronization is normally achieved by

regulating the flow of execution of a process



26/27

Types of processes

Concurrent and Serial processes

Two processes are concurrent if their execution

can overlap in time i.e. if the execution of the

second process starts before the first processcompletes.

Two processes are serial if the execution of one

must be completed before the execution of theother can start.



27/27

Types of processes

Concurrent processes generally interact througheither of the following mechanisms :

Shared Variables : The processes access(read or

write) a common variable or common data.

Message Passing: The processes exchange

information with each other by sending and

receiving messages.


Introduction to advanced OS

Documents

Transcript of Introduction to advanced OS