ns2 project in gujarat

ns2 project in gujarat


      ns2 project in Gujarat a key objective in designing VIP-FS is portability

If the file system is to be an extension to message passing

libraries, it must be portable across different libraries;

as such, the design must employ ns2 project in gujarat only features

which are common to most, if not all, message passing

libraries. Also, it must be capable of co-existing

with other (Unix based) data mariagment or network

file systems that may be employed Further, it must

\le capable of operating in ns2 project in gujarat heterogeneous distributed

system environments. the InterfaceItyer, the virtual parallel file (VPF) layer, and the

device driver (IDD) layer E’igure 1 illustrates

the logical configuration of VIP-FS The Interface layer provides a variety of file access

abstractions to the application program. For example,

I t may be a simple interface composed of standard

iinix open, close, read, write fiinclions ns2 project in gujarat Or, the file

system may accept, information describing the mapping

of a parallel file to a partitioned data doniain,

and transparently arbitrate access according to this

napping. The VPF layer defines ns2 project in gujarat and maintains a unified

global view of all file system components It pro\ides

1 he Interface layer with a single file image, allowing

each parallel file to be viewed as a single large file organized

as a sequential stream of bytes It achieves this

tiy organizing and coordinating access to the IIID’s

files in such a way that a global, ns2 project in gujarat parallel file is constructed

whose component stripes art’ composed of the

independent IDD files Any specification of a file offset

by the Interface layer is resolved by the VPF into

;in IDD address, file ID, and ID11 file offset

As shown, the IDD layer is built upon and conimuriicates

with the local host’s file system. It manages

each file as an independent non-parallel file and pro-

\ides a stateless abstraction to the VPF layer above ‘rhus, the IDD layer arts as the mediator betwemi the

local host file system and the VPF layer nication between layers within and across hosts is accomplished

through the use of message-passing library

primitives. In the following section ns2 project in gujarat we discuss the implementation

of VIP-FS. The discussion proceeds in a bottomup

manner, from the IDD layer to the Interface layer.

We begin with a brief description of the initialization

and configuration process. As ns2 project in gujarat  its primary function, the IDD layer is responsible

for communicating with the local file system and providing

a stateless interface to the VIP-FS layer. The

IDD layer is implemented in VIP-FS as a set of Unix

processes. The IDD supports a non-parallel (i.e., Unix stream)

view of files. It does not have knowledge of the logical

parallel file or of mapping functions; that is, it carries

no knowledge of how data is distributed among the

disk set or among the processors. All ns2 project in gujarat communication

with the IDD will take place through a icommunications

daemon. Requests will identify the requesting

taskid, the desired operation IDD processes receive file access requests from the

VPF layer in the form of messages sent through the

message-passing library being used. Requests can be

made for any of the standard Unix file ns2 project in gujarat access operations

such as open, close, read, write, etc.. The IDD

process performs the requested operatioii and sends

an appropriate response back to the ns2 project in gujarat VPF layer. The

IDD process has no notion of any global file space.