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NAND Flash and the FTL

Write logical blocks, watch the FTL remap them, run garbage collection, and track write amplification

NAND flash: 8 blocks × 8 pagesblock 0E:0block 1E:0block 2E:0block 3E:0block 4E:0block 5E:0block 6E:0block 7E:0host writes: 0NAND writes: 0erases: 0WAF: 0.00legend:freevalidinvalidmapped LBAs: 0free pages: 64 / 64
interactive modelWhat to watch

Use "write seq" to add the next logical block, or "write rand" to overwrite an existing one. Every host write lands on a fresh physical page, and old locations turn red when they become invalid. Run GC to copy any surviving data out of a victim block, then erase it.

Start with a host write. Watch the FTL place each LBA on a fresh physical page.

W = sequential write · R = random write · G = GC · T = TRIM · X = reset

Tap buttons to drive the SSD

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