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The complaint is that Apple's lack of TRIM support impacts performance on their SSDs; the Anandtech article says that this isn't the case. The fact that their S
by czhiddy 16y ago
The complaint is that Apple's lack of TRIM support impacts performance on their SSDs; the Anandtech article says that this isn't the case. The fact that their SSDs are slower than the competition is a separate argument.
- seabee 16y agoCorrect me if I'm wrong, didn't they also discover that it becomes a serious problem if you use over 90% of your drive space?
- stcredzero 16y ago"Doctor, it hurts when I do that." "Don't do that!"
- r0s 16y agoIt would be unavoidable. The controller writes to areas that haven't been written first, and not 'deleted' areas. "90%" capacity will be reached no matter how diligently the user prunes their files.
- stcredzero 16y agoThe controller writes to areas that haven't been written first, and not 'deleted' areas. [citation needed]
- r0s 16y agoGarbage collection in file systems? There's quite a bit to read. Lets stay on subject though: http://en.wikipedia.org/wiki/TRIM http://en.wikipedia.org/wiki/TRIM "Because of the way that file systems typically handle delete operations, storage media (SSDs, but also traditional hard drives) generally do not know which sectors/pages are truly in use and which can be considered free space. Delete operations are typically limited to flagging data blocks as "not in use" in the file system.[5][6] Contrary to, for example, an overwrite operation, a delete will therefore not involve a physical write to the sectors that contain the data. Since a common SSD has no access to the file system structures, including the list of unused clusters, the storage medium remains unaware that the blocks have become available."
- stcredzero 16y ago"The controller" is ambiguous, as there are multiple things that go by that name. This is a part of what I was getting at. So, if OS X always tries to reuse the "same blocks" doesn't that reduce the need for TRIM?
- r0s 16y agoAh, I meant the controller as chip-set on the SSD itself. From what I understand, if OSX did that, it would be TRIM, or some other analogous garbage collection. It doesn't though.
- stcredzero 16y agoUh, why would I be saying "yay, TRIM!" if I thought OS X already had TRIM? Here, "blocks" is ambiguous. On a rotating HD, OS X does use the same physical blocks. On an SSD, OS X tries mightily to addresses the same "blocks" but the SSD might move this mapping to different physical blocks. By doing this, OS X minimizes, as much as possible, the dirtying of "blocks" it doesn't have to, which means it puts the least burden possible on the SSD as it tries to do things like wear leveling. 3rd try. Please respond to what I'm actually saying.
- r0s 16y agoOkay. The wear leveling you mention actually creates the need for TRIM(garbage collection). Blocks - memory address space sections? What's ambiguous about this term? Here's more information about what TRIM does: http://www.bit-tech.net/hardware/storage/2010/02/04/windows-7-ssd-performance-and-trim/1 http://www.bit-tech.net/hardware/storage/2010/02/04/windows-... Once the disk is full, "dirty" blocks have to be re-used. Clearing those for writing adds time and bandwidth overhead that slows down write performance. So, the OSX "solution" is a temporary fix. However I'm pretty sure SSD write leveling behavior is standard across all other operating systems.
- stcredzero 16y ago