Jump to content
S Harber

Yosemite

Recommended Posts

Explanation of TRIM Enabler software (with a little less emphasis on the notion that Apple has done this terrible thing to prevent you from using non-Apple hardware):

 

from a reply to a question asked on a Mac site  -  

 

"There is nothing inherent in TRIM itself that is incompatible with Yosemite, and deleting system files won't affect this. A deleted file is inaccessible whether or not TRIM reclaims the physical SSD blocks it was stored in.

 

The problem is with the TRIM Enabler software itself. It works by modifying one of Apple's kernel extensions. Yosemite detects this alteration (via standard code-signing techniques), assumes that you've been infected by malware, and refuses to start, in order to minimize the damage. For the most part, this is good behavior. Code signing and the refusal to load unsigned code into the kernel is an important system security feature (and code signing is not something Apple invented for Yosemite).
 
Unfortunately, it ends up creating a terrible mess when you are deliberately altering one of Apple's kernel drivers. They can't tell if the alterations are safe (as in the case of TRIM Enabler) or if they are malware. So the only way to install TRIM Enabler is to disable the validation code that checks the code's signature. This allows TRIM Enabler to load and run, but also allows any other modified/unsigned kernel driver to load.
 
The "regular system maintenance" you're referring to is the fact that resetting NVRAM (aka "zap PRAM") will blow away the setting that disables code-checking. So after such a change, the kernel will once again validate the drivers, discover the alteration that TRIM Enabler installed, and refuse to boot. It's not a matter of deleting "certain system cache files" but the act of resetting your NVRAM parameters back to factory defaults that triggers the problem."

Share this post


Link to post
Share on other sites

You're right Al, TRIM is basically software that is written for a specific SSD to expedite certain functions and maintenance --- you could look at it like a utility application that has to run under the host operating system. It should also be noted that the manufacturers of SSDs don't always implement TRIM the same way. Not all SSDs are subject to this problem with Yosemite. 3rd Party company OWC, for example, builds TRIM functionality into their SSDs which does not interact with the OS in the same manner and they work fine with Yosemite or any other operating system.

 

I think the most important thing with this whole issue is to be aware of the potential that updating to Yosemite could disrupt any installed SSDs. This is of course quite crucial to know this before, particularly if you are using a 3rd Party SSD as the boot drive.

Share this post


Link to post
Share on other sites

The boat laptop is a 2009 MBP now booting on a OWC Mercury EXTREME Pro SSD installed  where the DVD drive used to be.

On Yosemite and no issues other than learning curves.

Share this post


Link to post
Share on other sites

After further investigation, I went ahead and upgraded to Yosemite.

If anything, I am experiencing that it made things better. For example, Safari is faster and battery life is better than under Mavericks.

 

** A note of caution to those who use NI: current versions of Komplete Kontrol and Guitar Rig 5 are not working under Yosemite, and will crash Logic and Pro Tools. 

Share this post


Link to post
Share on other sites

I have an early 2011 macbook pro that had an SSD drive that I installed last year. I "upgraged" to Yosemite, and...WHAMMO!   No workie. All the work arounds and fixes didn't work. Luckily I did a whole system backup before I did the upgrade, but I could not restore to the internal drive..since none of the workarounds would work. So I had to go get a new hard drive and restore the backup to that. I tried to put the old SSD drive in an external enclosure and mount that. Didn't work. I called the manufacturer (OWC) and I need to send the drive to them to see what they can do. So, I'm running Mavericks and I'll probably stay on that for a long time. Ever since Snow Leopard I feel each OS upgrade has been a downgrade, IMHO. I don't understand why Apple removed so many useful things. 

Share this post


Link to post
Share on other sites

bacon: " I don't understand why Apple removed so many useful things.  "

to make room for eye-catching shiny new things..?

 

actually, despite anything being 'removed', the OS's just keep getting more and more bloated, requiring more CPU HP, and memory and storage, just to turn on properly.

Share this post


Link to post
Share on other sites

Hey, Dave, with the research that I did it seems that OWC had SSDs that worked just fine with Yosemite because they built in TRIM function and support into the drive itself (so there were no issues and no need for operating system support). Hopefully OWC could do something for you in this regard. 

 

Some useful links:

TRIM support in Mavericks and Yosemite

 

Article from Mac site

 

OWC with built in TRIM support

 

post-1-0-96894100-1417370238_thumb.jpg

Share this post


Link to post
Share on other sites

The OWC person I spoke to on the phone was SUPER helpful, knowledgeable, and all around very nice. He said that I shouldn't be experiencing this problem. Maybe It was something else. The drive was working great up until I tried this, but I did have a power outage right at the start of the restore, but after that is seemed ok and then crapped out. I'm not blaming Yosemite, but I'm not going to upgrade to it as I've been looking at it through reviews and screen shots and they haven't improved anything for me. 

Share this post


Link to post
Share on other sites

"I'm not blaming Yosemite, but I'm not going to upgrade to it as I've been looking at it through reviews and screen shots and they haven't improved anything for me."

 

I updated all my machines to Yosemite and I have mixed feelings about the "look" of it all. That said, there have been hundreds of changes "under the hood" so to speak and I haven't found anything I don't like about it. The other thing to consider (which may not be such a big deal for you) is the integration of everything Apple providing you are running the latest OS on all devices. The level of integration that Apple has been able to achieve over many years (because they do both the operating system and the hardware) is one of the things I value the most.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×