Chapter 1
Concept
Spooling(
Simultaneously
Peripheral
Operation Online)
Batch
Def
Spooling is the
temporary storage
of data in disk for
later processing.
MultiProgramming
Time Sharing
Multi Processing
Jobs are collected
into a batch and
executed one after
another without
user interaction.
Multiple process in
main memory for
execution
1 CPU switches
between processes
very fastly to give
illusion of same time
execution
Two or more
cpu's tightly
coupled with
closed
communication
Process
It stores data in
disk and CPU
interacts with disk
through main
memory
Similar jobs are
grouped together
and CPU executes
them sequentially.
Each process gets the
CPU makes a context CPU for a fixed
switch
amount of time
(change the active
if process not
process) because of complete it goes to
process end or
end of queue
interrupt or need of
Can be bcz of
i/o devices' use
interrupt or need of
i/o devices' use
processes
running on
multiple CPUs
(also called
Parallel
execution
What improved
Overlaps I/O
operation for one
job while
CPU performs
another
Automatic
processing of
multiple jobs
less manual
intervention
Types
Chapter 1
Maximum CPU
utilization
Multiple processes
together and better
response
time
Shared
computer bus,
memory and I/O
devices with
multiprocessing
It is an extension of
MultiProgramming
Symmetric:Each
CPU has equal
right
Asymmetic:
Master slave
architecture
None
None
None
Advantage
cpu utilization
better than batch
OS
Good for large and
repetitive jobs
no continuous user
interaction
High CPU
utilization,less wating
Tasks have equal
time
oppurtunity
and response time,
increased throughput
Increased
Throughput
Cost Saving
Disadvantage
Not
multiprocessable,
no context
switching
Long
waiting/turnaround
time
no immediate
response
Difficult scheduling
and memory
management,
Paging and
fragmentation
More Complex
Overhead or
coupling reduce
throughput
Complex and require
Advance softwares
for multi users
1