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clintondyches
Posts: 27
Registered: ‎06-05-2012
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960GB M500 - Trim enabled upon installation on MacBook Pro?

So yesterday I received my 960GB M500. Cloning from my 512GB m4 went fine and the drive is working well (and much faster than the m4). However, when I was checking out the drive in System Information I noticed that Trim was already enabled. Is this normal?

 

Puzzled,

 

Clinton

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alex486
Posts: 236
Registered: ‎04-21-2012
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Re: 960GB M500 - Trim enabled upon installation on MacBook Pro?

[ Edited ]

Hi Clinton, when you enable TRIM in OS X, it is changing a kernel extension file (kext file).

You can edit it manually with a hex editor (make a backup first) or use a script or some other tool that makes the changes.

 

In mine (Mountain Lion) this is the file:

/System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

 

You can see the change that has been made by using the hexdump -C command or opening the file with a hex editor.

 

This is a section of the original kext for OS X 10.8.5 and we can see the string APPLE SSD which is needed before TRIM commands can be sent to the drive.

 

0000f3b0  74 61 74 65 4f 6e 57 61  6b 65 00 52 6f 74 61 74  |tateOnWake.Rotat|
0000f3c0 69 6f 6e 61 6c 00 41 50 50 4c 45 20 53 53 44 00 |ional.APPLE SSD.| 0000f3d0 54 69 6d 65 20 54 6f 20 52 65 61 64 79 00 4d 61 |Time To Ready.Ma| 0000f3e0 63 42 6f 6f 6b 41 69 72 35 2c 31 00 4d 61 63 42 |cBookAir5,1.MacB| 0000f3f0 6f 6f 6b 41 69 72 35 2c 32 00 41 50 50 4c 45 20 |ookAir5,2.APPLE | 0000f400 53 53 44 20 54 53 00 51 75 65 75 65 20 44 65 70 |SSD TS.Queue Dep|

 

This is a section of the modified kext for OS X 10.8.5 with the string removed.

 

0000f3b0  74 61 74 65 4f 6e 57 61  6b 65 00 52 6f 74 61 74  |tateOnWake.Rotat|
0000f3c0  69 6f 6e 61 6c 00 00 00  00 00 00 00 00 00 00 00  |ional...........|
0000f3d0  54 69 6d 65 20 54 6f 20  52 65 61 64 79 00 4d 61  |Time To Ready.Ma|
0000f3e0  63 42 6f 6f 6b 41 69 72  35 2c 31 00 4d 61 63 42  |cBookAir5,1.MacB|
0000f3f0  6f 6f 6b 41 69 72 35 2c  32 00 41 50 50 4c 45 20  |ookAir5,2.APPLE |
0000f400  53 53 44 20 54 53 00 51  75 65 75 65 20 44 65 70  |SSD TS.Queue Dep|

 

Once the modification has been made it applies to all SATA SSDs on the Mac, so if you change your SSD it sends TRIM commands to the new one too. So yes, what you see is normal.

 

Binary Boss
clintondyches
Posts: 27
Registered: ‎06-05-2012
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Re: 960GB M500 - Trim enabled upon installation on MacBook Pro?

Alex,

 

Thanks so much - I actually took the 'easy' way out and used Trim Enabler to turn TRIM off!

 

Clinton

Frontside Bus Driver
alex486
Posts: 236
Registered: ‎04-21-2012
0

Re: 960GB M500 - Trim enabled upon installation on MacBook Pro?

[ Edited ]

clintondyches wrote:

Thanks so much - I actually took the 'easy' way out and used Trim Enabler to turn TRIM off!


Don't you mean turn TRIM on?

 

In any case, there is nothing wrong with using the Trim Enabler tool and it is probably more reliable than making manual edits where you can easily make mistakes. But sometimes it is useful knowing that there is a way to compare the original and modified file and being able to verify that the tool did what it was meant to do.