SRAM and flash memory

Which correctly describes garbage collection in an SSD?

  1. AMoving valid data out of blocks that contain invalid data, then erasing those blocks to create free space
  2. BRemoving computer viruses
  3. CCompressing data
Show answer and explanation

Answer: A. Moving valid data out of blocks that contain invalid data, then erasing those blocks to create free space

NAND flash cannot be overwritten, and erasing can only be done in blocks. Old versions of rewritten data remain as invalid pages, so the controller gathers the valid data into another block and then erases the original block to create free space for new writes.

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More SRAM and flash memory questions

  1. In an SRAM read, what is the operation called that charges the bit lines in advance to the supply voltage or similar?
  2. Which electron injection mechanism is mainly used for writing (programming) NAND flash memory?
  3. In NAND flash, what is the phenomenon in which repeatedly reading the same block gradually shifts the threshold voltages of cells that are not being read?
  4. In QLC (4 bits per cell) NAND flash, how many threshold voltage states must one cell distinguish?
  5. In TLC and QLC SSDs, what is the main purpose of using part of the space as SLC to absorb writes temporarily?