ucayalifish / fcb_emulator

Project for emulation of NAND based FCB

Emulation of NAND based Flash Circular Buffer

The goal of the project is development of emulation for NAND based Flash Circular Buffer. Inspired by dhara flash translation unit project.

fcb_emulator's Issues

Adding tables for multiple blocks

• start new block buffer with incomplete header
• add small table
• add big table

1. calculate number of records that fit to available space in block
2. write table header
3. write data
4. commit block header

Enhance block state for erase

• random fatal failure to erase
• random non-fatal failure to erase (repeat recover)
• random non-fatal failure to erase (repeat does not recover)

Design in memory block reader/writer

Buffer for prepare data in memory for writing to a hole NAND erase block.
Writing to buffer must enforce 2-byte alignment.
Includes header for a block with a magic, identification of writing session, CRC32 and offset/size of written data.
CRC32 is calculated for data written, block header excluded.
Block is shuffled after writing.

Design fcb

Move usage statistics to block state

• add erase, write and read count etc. to block descriptor
• remove structure with global emulator statistics
• implement function that populates global statistics iterating blocks

Test data generation

• genrate big table with ~15 Mb total size and record size ~48 byte
• generate big table approximately 1 Mb with records ~200 byte
• generate table with single record ~180 byte

Port and adapt dhara's nand emulator

Impovment of NAND emulator

• add manufacturer bad blocks in emulator reset in predefined proportion
• add timebombs in predefined proportion excluding manufacturer bad blocks
• remove remnants of dhara error passing
• add functions returning erased/empty block status and marked bad block status
• remove remnants of dhare sector reading/writing