Media failure logic and Structure of Recovery manager

Media failure logic:

In the event of a hard system error (one non-volatile storage integrity), there should be minimum of lost work. Redundant copies of the object should be maintained, for illustration on magnetic tape that is stored in a vault. It is significant that the archive mechanism have independent failure modes from the regular storage subsystem. Therefore using doubly redundant disk storage would protect against a disk head crash but wouldn't protect against a bug in the disk driver routine or a fire in the machine room.

The archive mechanism intermittently writes a checkpoint of the data base contents to magnetic tape and writes a redo log of all update actions to magnetic tape, Then recovering from a hard breakdown is accomplished by locating the most recent surviving version on tape, loading it back into the system and then redoing every updates from that point forward using the surviving log tapes.

While performing a system checkpoint reasons relatively few disk writes as well as takes only a few seconds copying the whole database to tape is potentially a lengthy operation. Opportunely there is a (little used) trick one can take a fuzzy dump or an object by writing it to archive with an idle task. Following the dump is taken the log generated during the fuzzy dump is merged with the fuzzy dump to produce a sharp dump.

The particulars of this algorithm are left as an exercise for the reader.

Latest technology based Operating System Online Tutoring Assistance

Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Operating System help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Operating System, project ideas and tutorials. We provide email based Operating System help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Operating System. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Operating System Homework help and assignment help services. They use their experience, as they have solved thousands of the Operating System assignments, which may help you to solve your complex issues of Operating System. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.

2015 ©TutorsGlobe All rights reserved. TutorsGlobe Rated 4.8/5 based on 34139 reviews.