1.The process of establishing a link between two devices to communicate and share information is complex.
2. The communication functions are grouped into manageable sets called as layer.
3. The design process of layer architecture is very simple as the function of each layer and their interaction are well defined.
4. It provides flexibility to modify network services.
5. Addition of new services and management of network architecture is easy.
6. Due to segmentation it is easy to solve complex problems.
Structure of an Operating System
An operating system is composed of a
kernel, possibly some servers, and
posssibly some user-level libraries. The
kernel provides operating system services
through a set of procedures, which may be
invoked by user processes through
system calls. System calls look like
procedure calls when they appear in a
program, but transfer control to the kernel
when they are invoked at run time. ( read is
an example of a system call in Unix.)
In some operating systems, the kernel and
user-processes run in a single (physical or
virtual) address space. In these systems, a
system call is simply a procedure call. In
more robust systems, the kernel runs in its
own address space and in a special
privileged mode in which it can execute
instructions not available to ordinary user
processes. In such systems, a system call
invokes a trap as discussed below.
A trap is a hardware event that invokes a
trap handler in the kernel. The trap
indicates, in appropriate hardware status
fields, the kind of trap. Traps may be
generated implicitly by the hardware to
signal events such as division by zero and
address faults (which we will discuss later),
or explicitly by a process when it executes a
special instruction. Explicit or user-initiated
traps are used to handle system calls. A
system call stores the name of the call and
its arguments on the stack and generates a
user-initiated trap. The trap handler in the
kernel knows, from the type of the trap, that
it is a user-initiated trap asking for a system
call, finds the name of the systems call, and
calls the appropriate kernel procedure to
handle the call passing it the arguments
stored on the stack.
We will later consider the various techniques
for structuring the kernel. As we shall see,
kernels may be layered, object-oriented, or
decomposed into kernel processes.
Not all operating services have to be
provided by the kernel. Modern operating
systems also define servers, which are
user processes that offer operating system
services to other processes. These services
are invoked by clients through interprocess
communication (IPC) primitives. We shall
see later the rationale for transferring
functionality from the kernel to servers. We
shall also see the minimum functionality that
needs to be supported in the kernel. In
micorkernel-based systems, the kernel
provides this minimum functionality.
The cost of invoking system calls and IPC
primitives is more than the cost of invoking
a simple procedure call when multiple
address spaces are supported by the
system. Therefore, as we shall see later,
some of the traditional OS functionality is
sometimes also provided by user-level
libraries.
1. A set of layers and protocols is called as network architecture.
2. Protocol stach is defined as a list of protocols used for a certain system, one protocol per layer.
The OSI Model
what is a protocol architecture?
architecture
Computer architecture is not useful for the people whose use the computer for general purposes. Mostly, computer architecture helps those people who are in the manufacturing/development sector.
Computer architecture is the parts of a computer and how they relate together in helping it to carry out its purpose. It is a combination of instruction set design and micro architecture.
Computer hardware is the components that make up a computer. Computer architecture is the model used to combine the Hardware into a working unit.
The components and guidelines in making a good computer network tutorial are the definitions of computer network tutorial, the basics of computer network tutorial and the other guidelines and specifics of computer network tutorials.
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layered model architecture is tcp/ip model .you can reference this model as layered model architecture protocol.
layered model architecture is tcp/ip model .you can reference this model as layered model architecture protocol.
A layered network, or a network layer, is the set up of how data is sent over a network. Each layer has it's own responsibility by either capturing the data or routing it to a computer on the network.
No, this is not true at all. In a network, an almost unlimited number of computers can connect to another computer. The only limitations are the speed of the network connections, the speed of the computer, and the network architecture.
Micro kernel's have more fun. Where layered models tend to have drinking problems
Principles are not advantages or disadvantages of the layered approach, principles are behind the layered approachPrinciples:Data transmission error free.Minimum time for route discovery.Communication between layers through primitives.Congestion control for minimum delays and retransmission.Minimum effort in replacing new layer in the existing network layers.
http://wiki.answers.com/Q/What_is_client_server_Architecture"e http://wiki.answers.com/Q/What_is_client_server_Architecture"eClient server architecture refers to a network architecture whereby every computer on the network is either a server or a client.
Project 802
what is the architecture of database network
Rob Williams has written: 'Computer systems architecture' -- subject(s): Computer network architectures, Computer architecture 'Real-time systems development' -- subject(s): Real-time programming
Open Architecture Network was created in 2007.