Techquickie videos comments thread

mariushm · September 9, 2017

Couldn't find such a thread in LTT Official section, mabe there could be such a thread there where every time new video is posted, moderator can post link to video and then people comment or point mistakes?

For example for the SSD overprovisioning video... thought it would have been nice to mention out that some SSD controllers also store the information about where each block of data is mapped to,, and other useful information for controllers. SSD has to copy data constantly to pages in order to be able to erase blocks (garbage collection) and the controller needs to keep tracks of those data moves.

Also some SSDs can configure a portion of each memory chip in SLC mode where each cell will only hold 1 bit instead of 2 (in case of MLC chips)... this SLC memory will have a bit more endurance and is faster and therefore often used as a write cache , so that later data may be gradually transferred to the regular MLC pages. SanDisk used this trick but it's not the only one.

So it's not always as simple as difference between Gibibyte and Gigabyte

Some controllers with support for DDR3 memory for caching will often use those extra pages to quickly dump memory contents to ssd in case of power failure.

ps There are also some SSDs that have funky memory chips with odd number of layers and total size between the regular sizes like 16 GB, 32 GB, 64 GB per nand chip... i remember seeing a review for a SSD that used a controller with 4 channel but which had only 3 flash memory chips because it allowed for 240 GB with a significant overprovisioning, while saving money on nand chips.

Most controllers are either 4 channel or 8 channel and therefore most SSDs have multiples of 4 memory chips but this SSD was odd like that.