Apple adds SSD TRIM support to Mac OS X 10.7 Lion beta
Apple has added limited TRIM support to the latest developer release of Mac OS X 10.7 Lion, which should enhance the long term performance of Solid State Drives.
While Apple has already started incorporating SSDs into its Macs, it hasn't yet added TRIM, a specific type of operating system support intended to coordinate disk use between the system and the SSD controller. The feature was previously detailed as having "no" support in System Profiler (below, top).
The new Lion developer preview is reported to add TRIM support however, with users of Apple SSDs noting a "yes" (actually "oui") for support according to a report by the French blog MacGenerations (below, bottom).
Unlike conventional magnetic hard drives, SSDs must be erased before being rewritten with new data, somewhat similar to CD-RW disc. This housekeeping task can be managed by some SSD controllers, but the TRIM command is designed to keep SSDs efficiently optimized at all times, preventing a gradual decline in performance as garbage stacks up.
Cleaning up unused bits of deleted files on SSDs requires a sophisticated balancing act between making sure the drive is clean and ready for new write operations, while also limiting unnecessary wear, as the flash cells used by the devices wear out relatively quickly after a finite number of erase/write cycles, compared to the very long life of the recording surfaces of magnetic storage disks.
The TRIM command is part of the ATA interface standard. So far, it appears Apple's support in Lion is only activated for SSDs shipped by the company and not third party devices, but this is likely to be fleshed out more as Lion develops.
While Apple has already started incorporating SSDs into its Macs, it hasn't yet added TRIM, a specific type of operating system support intended to coordinate disk use between the system and the SSD controller. The feature was previously detailed as having "no" support in System Profiler (below, top).
The new Lion developer preview is reported to add TRIM support however, with users of Apple SSDs noting a "yes" (actually "oui") for support according to a report by the French blog MacGenerations (below, bottom).
Unlike conventional magnetic hard drives, SSDs must be erased before being rewritten with new data, somewhat similar to CD-RW disc. This housekeeping task can be managed by some SSD controllers, but the TRIM command is designed to keep SSDs efficiently optimized at all times, preventing a gradual decline in performance as garbage stacks up.
Cleaning up unused bits of deleted files on SSDs requires a sophisticated balancing act between making sure the drive is clean and ready for new write operations, while also limiting unnecessary wear, as the flash cells used by the devices wear out relatively quickly after a finite number of erase/write cycles, compared to the very long life of the recording surfaces of magnetic storage disks.
The TRIM command is part of the ATA interface standard. So far, it appears Apple's support in Lion is only activated for SSDs shipped by the company and not third party devices, but this is likely to be fleshed out more as Lion develops.
Comments
Will the SSD drive also start showing a decline in storage capacity when viewed in the OS?
(Even if I do have to do this, the speed increase with the Crucial 256 ssd is astounding! Well worth yearly maintenance)
"And "finite" = what number?"
Most flash memory specs state 100,000 write cycles or more, which is plenty for most uses.
Wear-leveling strategies will move around block of data periodically, so that rarely written files (i.e., OS or application binaries) and frequently-written files (swap files, business databases) even wear out the device and extent the usable life span.
Good news. Means I may not have to routinely restore my SSD to default configuration and re-image my drive.
(Even if I do have to do this, the speed increase with the Crucial 256 ssd is astounding! Well worth yearly maintenance)
lack of TRIM support is why I ended up buying an OWC SSD with a SandForce controller, no need to erase the drive on a regular interval.
I have an SSD and it shows "No" under TRIM support. Perhaps only Apple-installed SSDs are blessed.
OWC drives don't support TRIM. They don't need to, since they use a SandForce controller.
EDIT: nevermind, they do support TRIM. However, you still don't need it.
Good news. Means I may not have to routinely restore my SSD to default configuration and re-image my drive.
(Even if I do have to do this, the speed increase with the Crucial 256 ssd is astounding! Well worth yearly maintenance)
how do you go about doing that if I may ask? I could use it on my airs flash.
The Trim support is nice, but the shocker to me was the Recovery HD. Apparently, when you install Lion, it automatically makes a recovery partition for Recovery Mode and Disk Utilities. So now you don't need a disc to enter Recovery - all you do now is "option boot. This is further proof(to me) that Apple plans to abandon optical drives in the future.
hmm, very interesting, so how would this work exactly?
does anything equivalent have to be implemented on non-ssd flash storage? for example the flash memory on our iPhones?
i think so
i had to restore my 3GS as new a few weeks ago and the sync time for a few hundred songs suddenly dropped by A LOT when i put everything back on
hmm, very interesting, so how would this work exactly?
You hold down the "option" key when rebooting - You're then given the option to boot into the Recovery drive. You'll find all of the Disk Utility options, along with the ability to restore from Time Machine, and a new option to connect to you wifi network and open Safari in case you need online support during the recovery process.
how do you go about doing that if I may ask? I could use it on my airs flash.
I haven't done this and I'm not sure how to do this within OSX. It can be done using Windows 7 pretty easily (google Diskpart commands).
When/If I ever have to do this, I will use an external drive to boot my MBP, Launch Parallels, then wipe the ssd drive using Windows 7. From there I can restore my ssd from a cloned drive.
For the comment about OWC, never saw anything about those drives when researching SSDs. I'm kind of surprised, since I read so many comparisons with the Crucial SSD. With TRIM support coming, it maybe a moot point, but I'll keep these drives in mind for the future.
For the comment about OWC, never saw anything about those drives when researching SSDs. I'm kind of surprised, since I read so many comparisons with the Crucial SSD. With TRIM support coming, it maybe a moot point, but I'll keep these drives in mind for the future.
It's not just OWC drives, but any SSD with a SandForce controller. They are pretty nice drives though. They even make special ones to be used in RAID arrays.
OWC SSD
You hold down the "option" key when rebooting - You're then given the option to boot into the Recovery drive. You'll find all of the Disk Utility options, along with the ability to restore from Time Machine, and a new option to connect to you wifi network and open Safari in case you need online support during the recovery process.
This is so freaking great, I can't even express.
Can someone clarify why on earth anybody would want to use them?