ns2 project in South Dakota

ns2 project in South Dakota

      ns2 project in South Dakota while a user is allowed to run a program on a remote

node, he/she should not be allowed to access any

files on the remote nodes or change their system

properties without proper authorization. Although ns2 project in South Dakota basic security mechanism is available in Java to

protect selected node resources, it would nevertheless

be preferable if advanced security functions

were available so that access control and security

protocols can be easily defined and enforced

through the middleware. Job and Thread Naming: For an environment supporting

multiple parallel jobs, a unique job ID needs to

be assigned to each active job, which is needed to

control a specific job, for example, to kill a job. In

addition, each parallel job ns2 project in South Dakota consists of multiple

threads distributed among the nodes; therefore, a

thread ID is needed for each thread. The thread ID is

used to distinguish threads and ns2 project in South Dakota control the flow of

the parallel programs such as in ns2 project in South Dakota message passing.

For user threads to communicate, a mechanism to

provide a mapping between logical ns2 project in South Dakota thread IDs and

actual network addresses such as IP address and

network port is needed. User Commands: Users need commands to submit,

execute, and monitor their parallel programs and to

control the environment from a single point on the

cluster. Examples of these commands are to check

available resources and currently running parallel

jobs. These commands should ns2 project in South Dakota provide the user with

a single system image Any parallel application

requires some form of synchronization and control

to function correctly. Executing parallel applications on distributed environments makes these needs

even more important. Basic mechanisms to ensure mutual exclusion, ordered execution, and barriers are necessary for many programming models.


A distributed parallel application requires collective communications

at two different levels: at the job (or task) level

to deploy, monitor, and control users jobs, ns2 project in South Dakota and at the

process level for interprocess communications such

as broadcast and multicast. A programming model

can benefit from the middleware for both levels,

where efficient group communications methods can

be utilized. Distributed applications may also require

mechanisms to manage and control real-time

dynamic agent and process membership in the

system. These common requirements can be implemented in

different ways to provide the necessary ns2 project in South Dakota tools and APIs for

the programming model developer to build any of the

aforementioned programming models. However, each

model will also have its own set of functionalities that

need to be implemented as part of ns2 project in South Dakota the programming model

itself. For example, in a distributed shared memory or object

model, issues such as coherence and consistency must be

handled within the programming model ns2 project in South Dakota and independently

from the middleware, while in a message passing model, it

is left for the application developer to handle. In addition, some programming models can implement some functions

already available in the middleware to achieve specific

goals. For example, the communications functions in a

message-passing model can be realized using the ns2 project in South Dakota middleware

functions or directly in the model to support

specialized communications services that come with advanced

cluster networks such as the Sockets-GM for

Myrinet The middleware infrastructure is designed to satisfy the

requirements discussed above. This system ns2 project in South Dakota provides a pure

Java infrastructure based on a distributed memory model,

which makes it portable, secure, and capable of handling

different programming models (see Fig. 1) such as JOPI [23]

and the DSO model. The system has a number of

components that collectively provide middleware services,

including some of the requirements ns2 project in South Dakota described above, for a

high-performance Java environment on cluster and heterogeneous

systems. Software agent technology has been used in many systems

to enhance the performance and quality of their services