Structure of shared memory space related with the Distributed operating system

1. Name:-Punit Kumar Pandey
Roll No.:- 23
Class:- MCA-4th Sem.
Topic:- Structure of Shared Memory Space

2. Introduction
1. Structure define the abstract view of the shared
memory space to be presented to the application
programmers of a DSM system.
2. The shared memory space of one DSM system
may appear to its programmers as a storage for
words, while the programmers of another DSM
system may view its shared memory space as a
storage for data objects.

4. Types
There are three commonly used in a shared
memory space of a DSM system are:-
1. No Structuring
2. Structuring by data type
3. Structuring as a database

5. No Structuring
1. Most DSM system do not structure their shared memory
space.
2. The shared memory space is simply a linear array of word.
3. Advantage:-
a. It is convenient to choose any suitable page size as the
unit of sharing and a fixed gain size may be used for
all application.
b. It is simple and easy to design such a DSM system.

6. Structuring by data type
1. The shared memory space is structured either as a
collection of objects or as a collection of
variables in the source language.
2. The granularity in such DSM system is an object
or a variable.
3. DSM system use variable grain size to match the
size of the object/variable being accessed by the
application

7. Structuring as a Database
1. Structure the shared memory like a database
2. Shared memory space is ordered as an associative memory called
tuple space
3. To perform update old data item in the DSM are replaced by new
data item
4. Processes select tuples by specifying the number of their fields
and their values or type
5. Access to shared data is nontransparent. Most system they are
transparent

8. Thank u