Some questions about jasmine.h

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What is the difference between NUM_VPAGES and NUM_LPAGES?

and What is the difference between NUM_PSECTORS and NUM_LSECTORS?


Why do FTL_Greedy and FTL_Tutorial use only NUM_LPAGES?

I think that the exact page size of jasmine board is NUM_VPAGES, not NUM_LPAGES.

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NUM_VPAGES means that the number of virtual pages, it reflects that capacity of all flash chips on the Jasmine board.
Yes, the number of virutal pages of jasmine board is NUM_VPAGES.

For example, there are 8 Flash chips, each chip has 8GB, and the size of virtual page is 16KB. So NUM_VPAGES is 64GB/16KB = 0x400000.

There are some bad blocks in the flash chip, the firmware/metadata also consume some Flash pages, and the FTL must reserve some blocks for the garbage collection and run-time bad blocks. So the FTL reports a litter value to the host, for example, 60GB.

Then we get the NUM_LPAGES, NUM_LPAGES is 60GB/16KB, it is smaller than NUM_VPAGES.

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Further information about the question
If you use two-plane mode, the virtual page size goes to 32KB and also the virtual block size goes to 4096KB.
Sang-Phil Lim (M.S. Candidate Student)

VLDB Lab. (http://vldb.skku.ac.kr/)
Department of Embedded Software
Sungkyunkwan Univ., Korea.

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Thank you very much.
I understand!

Thank you very much, Victortan and Lsfeel0204. Thanks.


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