FlashMem_Simulator_2.0

NAND Flash Memory Simulater for Block Mapping Method with 2 Types of Mapping Table, Hybrid Mapping Method (BAST : Block Associative Sector Translation - 1:2 Block level mapping with Dynamic Table)

1) Static Table : Mapping table initially all correspond 1 : 1 (Logical Sector or Block Num -> Physical Sector or Block Num)
2) Dynamic Table : Mapping table initially all empty (non-assigned)

※ Additional implementation

- Garbage Collecter
	=> Because the cost of erasing operations is greater than reading and writing, 
	freeing up space for recording during idle time or through garbage collection at an appropriate time.

- Trace function
	=> Performance test through write operation by specific pattern.	

< Build Option >

• Modify this predefined macro as you want (Refer to "Build_Options.h")

Predefined Macro	For What
DEBUG_MODE	Trace all possible error situations (annotate to disable)
PAGE_TRACE_MODE	Trace wear-leveling per sector (page) for all physical sectors (pages) (annotate to disable)
BLOCK_TRACE_MODE	Trace wear-leveling per block for all physical blocks (annotate to disable)
SPARE_BLOCK_RATIO	The rate of spare blocks to be managed by the system for the total number of blocks (Blocks that cannot be record data directly) (Default : 0.08, 8%)
VICTIM_BLOCK_QUEUE_RATIO	Set the size of the Victim Block Queue to the ratio size of the total number of blocks in the generated flash memory (Default : 0.08, 8%)
VICTIM_BLOCK_DEBUG_MODE	Garbage Collector does not process the selected Victim Block after the end of the write operation (annotate to disable)

< Normal Mode (with not use Any Mapping Method) Command List >

Command	Action
init x or i x	Create x MB Storage File
read PSN or r PSN	Read data at Physical Sector Num(PSN) Position
write PSN data or w PSN data	Write data at Physical Sector Num(PSN) Position
erase PBN or e PBN	Erase data at Physical Block Num(PBN) Position
change	Change Mapping Method
clrglobalcnt	Clear Global Flash Memory Operation Count
pbninfo PBN	Output meta information for all sectors of PBN
info	Output Current flash memory information
exit	Terminate Program

< Block Mapping Method, Hybrid Mapping (BAST) Method Command List >

Command	Action
init x or i x	Create x MB Storage File
read LSN or r LSN	Read data at Logical Sector Num(LSN) Position
write LSN data or w LSN data	Write data at Logical Sector Num(LSN) Position
change	Change Mapping Method
print	Print Mapping Table(LSN -> PSN or LBN -> PBN)
searchmode	Change Algorithm for finding empty sector(offset) in block
trace	Write test with "W [TAB] LSN" format file
clrglobalcnt	Clear Global Flash Memory Operation Count (No dependency on each other between Per Block or Per Sector trace count)
forcegc	Force Garbage Collection to gain physical free space
ebqprint	Output Current Empty Block Queue (Only for Dynamic Table)
sbqprint	Output Current Spare Block Queue
vbqprint	Output Current Victim Block Queue
lbninfo LBN	Output meta information for all sectors of LBN
pbninfo PBN	Output meta information for all sectors of PBN
info	Output Current flash memory information
exit	Terminate Program after empty the Victim Queue by GC

< Bugs and needs to be improvement >

• All known bugs fixed
  
  
  

< Trace Result >

• You can see the trace results here.
  
  
  

< References >

• A survey of Flash Translation Layer :
  https://www.sciencedirect.com/science/article/abs/pii/S1383762109000356
  
• A SPACE-EFFICIENT FLASH TRANSLATION LAYER FOR COMPACTFLASH SYSTEMS :
  https://ieeexplore.ieee.org/document/1010143
  
• A Log Buffer-Based Flash Translation Layer Using Fully-Associative Sector Translation : https://dl.acm.org/doi/10.1145/1275986.1275990
  
• Micron Technical Note - Garbage Collection :
  https://www.micron.com/-/media/client/global/Documents/Products/Technical%20Note/NAND%20Flash/tn2960_garbage_collection_slc_nand.ashx
  
• Micron Technical Note - Wear-Leveling Techniques in NAND Flash Devices :
  https://www.micron.com/-/media/client/global/documents/products/technical-note/nand-flash/tn2942_nand_wear_leveling.pdf