4. Distributed System is collection of coupled
processor interconnected by a communication.
Processors variously called nodes computer,
machines, host.
5.
6. Resource Sharing:
. Sharing and printing files at remote sites.
Computing Speedup:
. Communication : message passing
file transfer , mail, etc
7. There are two types of distributed system
structure:
Network operating system
Distributed operating system
8. Users are aware of multiplicity of machines not
transparent and more difficult to use.
Distributed Operating System
Users not aware of multiplicity of machines
access to remote resource similar to access to local
resource.
. Data Migration
.Computation Migration
10. Local Area Network (LAN) :
Designed to cover small geographical area.
Nodes are terminals , workstation , PCs , and
or a few (one or more) mainframes.
11.
12.
13. Site in the system can be physically connected in a
variety of ways: they are compared with respect
to the following criteria.
Basic Cost
Communication cost
Reliability
14.
15. The design of a communication network must
address from basic issues:
1. Naming and name resolution
2. Routing Strategies
3. Connection Strategies
4. Contention
16. . Name system in the network
. Address message with the process _ id
. Identify processes on remote system by.
<host _ name , identifier > pair
17. Fixed Routing:
Since the shortest path is usually
chosen communication cost are minimized.
Virtual Circuit:
Ensure that message will be
delivered in the order in which they were sent.
Dynamic Routing:
Usually a site sends a message to
another site on the link least used at that
particular time.
18. Circuit Switching:
A permanent physical link is established for
the duration of the communication (i.e. telephone
system )
Message Switching:
A temporary link is established for the
duration of one message transfer. (i.e. post office
mailing system)
Packet Switching:
Each packet may take a different path
through the network.
19. Several sites may want to transmit information
over a link simultaneously.
To avoid repeated collision
CSMA/CD: Carrier sense with multiple access
collision detection.
20. Physical layer
Data Link layer
Network layer
Transport layer
Session layer
Presentation layer
Application layer
21. The term structural system or structural frame in
structural engineering refers to load-resisting sub-
system of a structure. The structural system
transfers loads through interconnected structural
components or members.
22. Process Management
Main Memory Management
File Management
I/O System Management
Secondary Storage Management
Networking
Protection System
Command Interpreter System
23. A process is a program in execution. A process is
an active entity.
A process needs certain resources ,including Cpu
time memory , file and I/o devices to accomplish
it task
Main Memory Management
Memory is a large array of words or bytes , each
with its own address. It is a repository of quickly
accessible data shared by the Cpu and I/O
devices.
24. A file is collection of related information defined
by its create commonly file represent program
(both source and object forms) and data.
I/O system Management
OS hides the specific hardware of I/O devices
from the users.
25. The processors in the system are connected
through communication lines (high speed buses
or network)
Protection System
Uses must be protected during the concurrent
execution of multiple process.
Different mechanism are used to provide to
different resources.
Command Interpreter System
Most important system component being an
interface between the user and os.
26. MS-DOS was written to
provide the
functionality in the
space.
It was not divided into
modules carefully.
Unix- limited by hardware
functionality the original
UNIX operating system
had limited structuring .
The Unix OS consists of
two separate parts.
System Program
The Kernel
