This document discusses process management and cooperation between processes. It defines independent and cooperating processes, with independent processes unable to affect or be affected by other processes, while cooperating processes can. Reasons for process cooperation include information sharing, speeding up computation by dividing tasks, modularity, and convenience. The producer-consumer problem is provided as an example of cooperating processes, where a producer process generates items for a consumer process to use.

1. Understand Process Management
• Relationship Between Processes
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2. Recap
In the last class, you have learnt
• Process Creation
• Process Termination
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3. Objectives
On completion of this class, you will be able to
know
• Relationship between Processes
• Reasons for providing an environment that allows
Process cooperation
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4. Relationship Between Processes
• Concurrent processes executing in the operating system may be
either “Independent processes” or “Cooperating processes”
• A process is independent if it cannot affect or be affected by the
other processes executing in the system
• A process that does not share any data with any other process is
independent Process
• A Process is a cooperating, if it can affect or be affected by the
other processes executing in the system
• Any process that shares data with other processes is a
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cooperating process

5. Relationship Between Processes
Reasons for Process cooperation
• Information sharing
• Computation speedup
• Modularity
• Convenience
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6. Relationship Between Processes
Information Sharing
• Several users may be interested in same piece of information,
Ex. Shared file
• Must provide an environment to allow concurrent access to
these types of resources
Computation Speedup
• To run a particular task faster, we must break it into subtasks
• Each of the subtask will execute in parallel with others
• This is possible only if computer has multiple processing
elements ( CPU or I/O channels)
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7. Relationship Between Processes
Modularity:
• For cooperating between systems we have to construct the
system in a modular fashion
• Dividing the system function into separate processes or
threads
Convenience:
• Even an individual user may work on many tasks at the same
time
• For instance, a user may be editing, printing and compiling in
parallel
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8. Cooperating Processors
• Concurrent execution that requires cooperation among the
processes requires mechanisms to allow processes
communicate with one another
• To illustrate the concept of cooperating processes look at the
– Example: Producers-consumers problem
• A producer process produces information that is consumed by
a consumer process
– Example :
• A print program produces character that are consumed
by the printer driver9CM402.14 8

9. Cooperating Processes
• To concurrently run producers and consumers processes we
must have a buffer of items that can be filled by the producer
and emptied by the consumer
• A producer can produces one item while the consumer is
consuming another item
• The producer and consumer must be synchronized, so that
– the consumer does not try to consume an item that has not yet been
produced
• The consumer must wait until an item is produced
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10. Example
• Solutions to producer-consumer problem may implement the
buffer interface shown follows
Interface for buffer implementation
Public interface Buffer
{
// producers call this method
public abstract void insert (object item);
// consumers call this method
public abstract object remove( );
}
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11. Example
• The producer process involves the insert( ) method when It
wishes to enter an item in the buffer
insert( ) method
Public void insert (object item){
While (count= = BUFFER SIZE)
; // do nothing - - no free buffers
+ + count;
buffer [in]=item;
in=(in+1) % BUFFER -SIZE;
}
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12. Example
• The consumer calls the remove( ) method when it wants to consume an item
from the buffer
remove method
Public object remove ( ) {
Object item;
While (count= = 0)
; // do nothing - - nothing to consume
// remove an item from the buffer
--count;
item=buffer [out];
out=(out+1) % BUFFER _ SIZE;
return item; } 9CM402.14 12

13. Summary
In this class, you have learnt
• Relationship between the processes
• Reasons for Process cooperation
• Cooperating Processes
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14. Frequently Asked Questions
1. Explain about cooperating process
2. What are the several reasons for cooperating processes
3. Explain about the relationship between processes
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15. Quiz
1. A process is ____________ if it cannot affect or be
affected by the other processes executing in the system
a) Independent
b) Dependent
c) Cooperating
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16. Quiz
2. A process is ________ if it can affect or be affected by
other processes executing in the system.
a) Cooperating
b) Independent
c) Dependent
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17. Quiz
3. A process that does not share any data with any
other process is
a)Independent Process
b) Cooperating
c) Dependent
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18. Other subject materials
• Web designing
• Micro processors
• C++ tutorials
• java
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