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Review Question 1 of Introduction to Operating Systems

Consider a hypothetical 32-bit microprocessor that has 32-bit instructions composed of two fields. the first byte contains the opcode and theRemainder an immediate operand or an operand address.

  • What is the maximum directly addressable memory capacity (in bytes)?

2(32-8) = 16,777,216 bytes = 16 MB

  • Discuss the impact on the system speed if the microprocessor data bus has
  • a 32-bit local address bus and a 16-bit local data bus.

Instruction and data transfers would take three bus cycles each - one for the address and two for the data.

  • a 16-bit local address bus and a 16-bit local data bus.

Instruction and data transfers would take four bus cycles each - two for the address and two for the data.

  • How many bits are needed for the program counter and the instruction register?

24 bits for the PC (24-bit addresses), 32 bits for the IR (32-bit addresses)

In virtually all systems that include dma modules, dma access to main memory is given higher priority than processor access to main memory. why?

If a processor is held up in attempting to read or write memory, usually no damage occurs except a slight loss of time. However, aDMA transfer may be to or from a device that is receiving or sending data in a stream (e.g., disk or network), and cannot be stopped. Thus, if the DMA moduleis held up (denied continuing access to main memory), data will be lost.

Why does a batch system need memory protection? why does a multiprogrammed batch system need memory management and scheduling? why do bothTypes of systems need interrupts?

A batch system needs memory protection so that programs can't modify the monitor.

A multiprogrammed batch system needs memory management so that multiple jobs can be kept in memory at the same time. Memorymanagement will determine which portion of memory each job can use. The system also needs a scheduling algorithm to determine which job can run at any giventime.

Both types of systems need interrupts so that the operating system can regain control of the CPU. A batch system needs this totime-out a long job and a multiprogrammed system needs this to share the processor among the active processes.

What is the purpose of system calls, and how do system calls relate to the operating system and to the concept of dual-mode (kernel mode and userMode) operation?

With a time sharing system, the primary concern is turnaround time. A round-robin scheduler would given every process a chance torun on the CPU for a short time, and reduce the average turnaround time. If the scheduler instead let one job run until completion, then the first job wouldhave a short turnaround time, but later ones would have to wait for a long time.

In a batch system, the primary concern is throughput. In this case, the time spent switching between jobs is wasted, so a moreefficient scheduling algorithm would be first-come, first-served, and let each job run on the processor as long as it wants.

In ibm's mainframe operating system, os/390, one of the major modules in the kernel is the system resource manager (srm). this module isResponsible for the allocation of resources among address spaces (processes). the srm gives os/390 a degree of sophistication unique among operating systems.No other mainframe operating system, and certainly no other type of operating system, can match the functions performed by srm. the concept of resourceIncludes processor, real memory and i/o channels. srm accumulates statistics pertaining to utilization of processor, channel and various key data structures.Its purpose is to provide optimum performance based on performance monitoring and analysis. the installation sets forth various performance objectives, andThese serve as guidance to the srm, which dynamically modifies installation and job performance characteristics based on system utilization. in turn, the srmProvides reports that enable the trained operator to refine the configuration and parameter settings to improve user service.

This problem concerns one example of SRM activity. Real memory is divided into equal-sized blocks called frames, of which there maybe many thousands. Each frame can hold a block of virtual memory referred to as a page. SRM receives control approximately 20 times per second and inspects eachand every page frame. If the page has not been referenced or changed, a counter is incremented by 1. Over time, SRM averages these numbers to determine theaverage number of seconds that a page frame in the system goes untouched. What might be the purpose of this and what action might SRM take?

Questions & Answers

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.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
analytical skills graphene is prepared to kill any type viruses .
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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