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If the entire image must be in main memory, then the image must be small and only a limited number of processes can be active at anytime. This problem can be solved by using virtual memory, so that only a portion of the process image (the portion currently being used) needs to be in memory atany given time.

It states that unix is unsuitable for real-time applications because a process executing in kernel mode may not be preempted. elaborate.

Because there are circumstances under which a process may not be preempted (i.e., it is executing in kernel mode), it is impossiblefor the operating system to respond rapidly to real-time requirements.

Use the ps program to list all the processes running on a linux machine (including system processes and processes for all users). list oneProcess for each unique state that is listed (i.e. one per unique entry in the state column) and describe what state this process is in. see the manual pageFor help with ps. next, create five new processes in quick succession and leave them running. using ps, list their process identifiers. is there any relationBetween the identifiers they are assigned?

You can use ps ax to list all the processes on a Linux machine. Here is a list of some of the processes I found:

PID TTY STAT TIME COMMAND

1 ? S 0:04 init [3]

2 ? SN 0:00 [ksoftirqd/0]

3 ? S<0:02 [events/0]

4 ? S<0:00 [khelper]

9 ? S<0:00 [kthread]

18 ? S<0:06 [kacpid]

118 ? S<0:00 [kblockd/0]

176 ? S 0:00 [pdflush]

179 ? S<0:00 [aio/0]

178 ? S 0:01 [kswapd0]

771 ? S 0:04 [kseriod]

829 ? S<0:00 [ata/0]

843 ? S<0:00 [reiserfs/0]

983 ? Ss 0:00 /sbin/devfsd /dev

5192 ? S 0:00 [khubd]

6328 ? Ss 0:00 metalog [MASTER]

6332 ? S 0:00 metalog [KERNEL]

6366 ? Ss 0:00 /usr/sbin/acpid -c /etc/acpi/events

6991 ? Ss 0:00 /usr/sbin/cupsd

7326 ? Ss 0:00 /usr/sbin/fcron

7422 ? Ss 0:00 /usr/sbin/speedfreqd -P /var/run/speedfreq.pid -p pow

There are many more. The TTY column indicates whether the process is attached to a termanl, and STAT gives the state of the process.Most processes are sleeping (S), one has been given a low priority (N), and others have been given a high priority (<). Notice that typically important system processes have a high priority.

If you create five processes in quick succession, they will typically have sequential process identifiers.

How is a process switch different from a mode switch?

A process switch involves the operating system having to do a lot of work, whereas a mode switch is done completely in hardware. Amode switch involves saving the state of the current process (in hardware), changing to supervisor mode, then giving control to the operating system. Theidea is that the operating system will execute a short handler, then return control to the processor. The processor will restore the state of the originalprocess and continue.

With a process switch, the operating system must give control of the CPU to a different process, rather than resuming with theprevious process that was running. Thus it must save the context of the current process in its PCB, update the PCB state and accounting information, move thePCB to a new queue, execute the scheduling algorithm to choose a new process,remove the PCB of that process from the ready queue, update its memory management structures, and restore its context into the processor.

Questions & Answers

Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
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Source:  OpenStax, Operating systems. OpenStax CNX. Aug 13, 2009 Download for free at http://cnx.org/content/col10785/1.2
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