4 ms·
They don't do transaction systems on these cards? That's like "Writing to a Consumer File System 101". Yike.
by kabdib 12y ago
They don't do transaction systems on these cards?
That's like "Writing to a Consumer File System 101". Yike.
- userbinator 12y agoI'd say that they certainly try to, but the block-erase and page-program granularity of NAND flash makes it pretty much impossible to guarantee any atomicity of operations without ridiculously wasting the capacity. Furthermore, pages within a block can only be programmed sequentially to avoid corrupting previously programmed pages (this is known as "program disturb"), and each page can only be programmed once, also to avoid program disturb effects.
- kabdib 12y agoInteresting. I'm surprised that NAND flash chips don't have some kind of hardware assist for this (e.g., really small pages for handling the much smaller checkpoint writes). But I guess at the level of utterly fungible consumer hardware it's about cost rather than reliability, since the latter doesn't have any absolute metrics.