2
I've been looking at logical and physical block sizes for disks...
[old disks] logically(4KB) -> physically(8 * 512B) -------Data Cluster
[new disks,old OS] logically(4KB) -> physically(4KB(8 * 512B)) ------AF *512e Mode
[new disks,new OS] logically(4KB) -> physically(4KB) -------4K Native Mode
But I'm new to SSDs, and been reading (see below) that SSDs don't have physical sectors they have physical pages... and those pages get "logically" associated to what is called a block on SSD.
SSD layout In contrast to the hard disk, a SSD consists of semiconductor memory building blocks, it contains no mechanical parts. The smallest unit of an SSD is a page, which is composed of several memory cells, and is usually 4 KB in size. Several pages on the SSD are summarized to a block. A block is the smallest unit of access on a SSD. Currently, 128 pages are mostly combined into one block; therefore, a block contains 512 KB.
Questions:
- Are SSDs made in other page/block sizes other then this (4KB/512KB)?
- If the SSDs "block size" comes in 512KB
- can I logically address(4KB) -> physical(4KB)?
- or even, logically(512KB) -> physical(512KB(128 * 4KB))?
I don't know how I didn't see those sizes on that wikipedia page... – Jordan Davis – 2015-09-22T00:18:06.220
what is (+128) for?
64 pages of 4,096+128 bytes each for a block size of 256 KiB
– Jordan Davis – 2015-09-22T00:19:55.4601@JordanDavis From the same wikipedia article "associated with each page are a few bytes (typically 1/32 of the data size) that can be used for storage of an error correcting code (ECC)". That's what the +128 is for ;-) – misha256 – 2015-09-22T00:29:53.537