Slashdot Mirror
Apple Disables Trim Support On 3rd Party SSDs In OS X
MojoKid (1002251) writes One of the disadvantages to buying an Apple system is that it generally means less upgrade flexibility than a system from a traditional PC OEM. Over the last few years, Apple has introduced features and adopted standards that made using third-party hardware progressively more difficult. Now, with OS X 10.10 Yosemite, the company has taken another step down the path towards total vendor lock-in and effectively disabled support for third-party SSDs. We say "effectively" because while third-party SSDs will still work, they'll no longer perform the TRIM garbage collection command. Being able to perform TRIM and clean the SSD when it's sitting idle is vital to keeping the drive at maximum performance. Without it, an SSD's real world performance will steadily degrade over time. What Apple did with OS X 10.10 is introduce KEXT (Kernel EXTension) driver signing. KEXT signing means that at boot, the OS checks to ensure that all drivers are approved and enabled by Apple. It's conceptually similar to the device driver checks that Windows performs at boot. However, with OS X, if a third-party SSD is detected, the OS will detect that a non-approved SSD is in use, and Yosemite will refuse to load the appropriate TRIM-enabled driver.
Apple has never enabled TRIM on non-OEM SSDs, which is probably the conservative and correct thing to do. If you're clever enough to install a new SSD, you're clever enough to enable it on your own (and presumably to know whether you should enable it, and whether it's even a benefit for your particular drive).
The current workaround involved a single software vendor who didn't sign their kexts. Apple's new security policy won't let you load random unsigned kernel modules unless you explicitly turn off the signature checking. While this is inconvenient for me personally - because I have a 3rd-party SSD and I used that software myself - on whole, I'd rather have a more secure OS than the dubious benefit of a possibly slightly faster SSD.
Dewey, what part of this looks like authorities should be involved?
Also - couldn't you actually just sign the drivers that are needed for trim? What prevents that?
As the author of the popular "trim enabler" software (which patches the original apple drivers and so causes the original drivers to fail the kext signing check) puts it:
"all of Apple’s AHCI SATA drivers are closed source and undocumented, which makes it impossible for me to create my own Trim driver and get it signed."
Which is also the reason why there are no trim drivers available from hardware manufacturers like Samsung, etc. No access to Apple's driver documentation - no signed trim drivers.