11.18 수업 필기

11.18 수업 필기


sector sparing

slip sparing

track skewing

track buffering


disk performance

Disk latency = Seek Time + Rotation Time + Transfer Time


Disc Scheduling


Disc Scheduling

Shortest Seek Time First

Shortest seek time first

optimal funnest: ????? what is this ????




==skip flash mem===

Storage Update Problem

Transaction Concept





The crash can happen anytime when tyo u reboot nexttime\How to solve this? If you have some extra information then you can solve this

Impementing Transactions

Challenge In-place

Redo logg

I want to update this

Fedo logging

When you done it should be at the end 9Some bad thing happen

Thend you need unload

Garbage collectin

Redo logging

Recovery with redo logging

we create the transaction field when yo u find the commit transection then alllied to if you ddefine drawback or tyo ucan you can not update all of the updates in  That is what it b. any other transacionnnnnn before transaction start and i want to trransfer 100 dollor idono

u commit appl htis vao=lue and then now u done. if u do dhis in the middle of transacion commit in the start

there is no commit operaion u do not know that consitudes garbage collect dasfaa i will be dead when u reboot aa

Implementation Details

i do not want to read

u sh ou ld write 24each time u update

Repeated writebacsordering constraint think about the performance

Smaller performance

without transic concept that approad=ch fine grained Group commitIf uo can not asdfglglglglgl 9MB example

maximum lll

you have right sitiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii you write lag=rhe data looriginal view metadataFedo Log ImplementationAfter the commission Garbatg=e colloe=ct gc loghead here we have both of memory that guy is this guy is already. write back is already butIn Use Free Available for new records Mixed WBCCompleteCommitted Anouncement As a portion of




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