CCleaner and TRIM Interaction In Windows 7

[JG in SB]

Hi,

 

I have recently switched over to SSD's on both of my main systems. These systems are both running Windows 7 Professional 64-bit and this operating system supports the TRIM function on SSD's. Additionally, all of the SSD's I use have firmware that enables the TRIM function. So I know for certain that when I perform a normal delete in Windows 7, that the TRIM function is being passed down and executed by my SSD's.

 

I have two (2) questions...and neither of them are whether CCleaner is a TRIM replacement...so please read them before you refer me to the other threads related to TRIM in this forum:

 

1. If an item is deleted by CCleaner (using simple deletion...not overwriting secure deletion) does this delete action pass the TRIM command down to my SSD the same way that performing a delete function with the Windows 7 O.S. does (like when you empty the recycle bin)?

 

2. Does the TRIM function obviate the need for secure overwrite deletion? My understanding is that TRIM tells the SSD that a given cell is now available for data writing without having to "read" any data from that cell, but does that mean the original data is still present and retrievable? Is there a current feature within CCleaner to provide a secure overwrite feature for SSD's?

 

Any and all information is greatly appreciated. Thanks in advance.

 

Jarrett

[hazelnut]

A very interesting question indeed Jarrett and not one that I know the answer to. In fact TRIM was not something I really knew anything about.

 

I found a page here which explains it very well indeed, and so I now understand why you actually asked your question.

 

http://www.maximumpc.com/article/features/...er_trim_command

 

Hopefully some others may have some imput here.

 

Welcome to the forum

[DennisD]

Same as hazel. I've been reading this to enlighten myself:

 

http://en.wikipedia.org/wiki/TRIM

 

Probably one for the devs to answer, although we do have members running Windows 7 who may have some positive input.

[JG in SB]

Hi,

 

Thanks for the welcome and the additional information. If somebody can tell me how CCleaner's deletion works on regular (i.e. non-SSD) drives then I think I can figure out the answer to this. For example, if the O.S. treats a file deletion by CCleaner the same way it treats a deletion by emptying the Recycle Bin, then we can probably assume a CCleaner deletion on an SSD passes the TRIM command down to the drive.

 

In other words, if the O.S., doesn't differentiate between different methods of file deletions...just treats them all as "deletions" regardless of how or where they are initiated, then we probably have our answer to the 1st question. Still need an answer for the 2nd part.

[DennisD]

Hi Jarrett.

 

It doesn't appear that us volunteer members know enough about your query to give you a definitive reply.

 

With it being a holiday period, the developers may be in short supply until things are back to normal, so I'm just giving your thread a bump to keep it current.

 

Then again, we have different members using the forum at different times, so you may still get some input in the meantime.

[JG in SB]

Hi Jarrett.

 

It doesn't appear that us volunteer members know enough about your query to give you a definitive reply.

 

With it being a holiday period, the developers may be in short supply until things are back to normal, so I'm just giving your thread a bump to keep it current.

 

Then again, we have different members using the forum at different times, so you may still get some input in the meantime.

 

Any updates on this. I am inquiring again to make this current and hopefully hear something. Thanks!

[JG in SB]

OK. I am now running TRIM-enabled Intel X25-M SSD's in my two primary computer systems, on which I also run CCleaner. Does anyone know what the interaction is between CCleaner and the TRIM function? If CCleaner deletes a file, is it the same as me deleting it through the Recycle Bin? If I overwrite a file using secure file deletion, will Windows 7/TRIM view this as as "write" rather than a "delete" and will this ultimately interfere with TRIM functionality? I bet there are a lot of CCleaner users that also use SSD's and would love to get any feedback about this.

 

Thanks in advance.

[_ccleaner_]

CCleaner uses the DeleteFile API to delete files, but I don't know if W7 has enhanced this API to accommodate TRIM.

 

As far as Secure Deletion, it is always good to overwrite the files before deleting them as it seems that SSDs drives has the caching and erasing process moved out of the time-sensitive write cycle and into the time between the actual deletion and the next write. So, from what I understood files might be around for a period of time...I think...

 

Have you experienced any slowdowns after using CCleaner? I believe you have already run out of "fresh blocks to write" in your new drives so if you continue to use CCleaner pretty soon you will notice a slowdown if CCleaner is not causing TRIM command to be pass down to SSD. Let us know...

 

I hope this helps.

[JG in SB]

CCleaner uses the DeleteFile API to delete files, but I don't know if W7 has enhanced this API to accommodate TRIM.

 

As far as Secure Deletion, it is always good to overwrite the files before deleting them as it seems that SSDs drives has the caching and erasing process moved out of the time-sensitive write cycle and into the time between the actual deletion and the next write. So, from what I understood files might be around for a period of time...I think...

 

Have you experienced any slowdowns after using CCleaner? I believe you have already run out of "fresh blocks to write" in your new drives so if you continue to use CCleaner pretty soon you will notice a slowdown if CCleaner is not causing TRIM command to be pass down to SSD. Let us know...

 

I hope this helps.

 

Thanks. This is helpful information. To begin with, I have not noticed any slowdown in my drives sinceusing CCleaner. Second, I did not realize that the overwrite occurs before deletion in "secure deletion". I just thought that on a normal drive, the data gets overwritten several times with random o's and 1's and therefore it is effectively deleted. My understanding now is that, CCleaner FIIRST overwrites the file with random data,and THEN it deletes it like a normal deletion. That is good news.

 

So the real answer to the question is what is the interaction between DeleteFile API and TRIM. I will do some research on this and get back to the thread with findings.

 

Thanks for the info.

[_ccleaner_]

My understanding now is that, CCleaner FIIRST overwrites the file with random data,and THEN it deletes it like a normal deletion.

 

Correct. CCleaner uses DeleteFile API in both cases. With SD, it first overwrites and then deletes it.

 

Let us know about your research...

 

Thanks

[DennisD]

Some really informative posting there about SSD's. Nice one, and bookmarked.