Solid State Drives on a Mac

1. The folks at BestBuy know nothing about Macs.
2. If you wish to delete a program dragging it to the Trash will delete 99% of it. There may be some preference files around but they occupy minimal space. Not an issue. It's very simple to find left over stuff after you trash an app.
3. None of the issues you propose are germain to solid state drives.

telon175,

Also, at no time does OS X defragment a drive, either a boot drive or a secondary drive. What is does do is write to drives in a way that reduces fragmentation to an absolute minimum. Because of this, fragmentation rarely becomes an issue for most users, and utilities designed to defrag a drive are not necessary.

The only real benefit that a solid state drive has over a traditional hard drive at present is durability. There have been no tests that show performance is enhanced by using a solid state drive, nor has it been shown that solid state drives improve battery life (not by any significant amount).

Scott

"This guy worked for Apple at Best Buy."

The guy works for BestBuy not Apple.

Dear Scott,

I am going to have to disagree with you, please refer to this article concerning solid state drives and their performance capabilities.

http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3403&p=1

Performance is most certainly enhanced with an SSD.

Although I'm relying on my own testing, the fact that there are no moving parts and any part of the SSD can be accessed nearly instantaneously vs. the system having to wait while the hard drive's head is mechanically positioned makes a huge difference in performance.

I will never go back to a hard drive for my system drive if at all possible.

Scott Radloff wrote:
Also, at no time does OS X defragment a drive, either a boot drive or a secondary drive.

Not true, OS X does automatically defrag files that are 20MB in size and under. But it doesn't do it at shutdown like the Best Buy guy said, instead it's always doing it in the background.

What is true is that this has nothing to do with solid state drives, since random access is just as fast as sequential.

Defragging isn't going to destroy data on an ssd, all it does is reduces the life of the drive because
there are only so many times data can be written to disk before the sectors in question wear out, but
it is a number much higher than a standard hard drive, I would ignore it for all practical purposes.
Leopard defrags small files, but it also has a habit of rewriting them in a different spot when it does,
so the automatic defrag process will have minimum effect on the SSD's life span, in fact it may
improve the life span of the drive because temp files that are constantly reading and writing to disk
will be moved occasionally to a new area on the disk instead of wearing out one spot continuously.

Defragging an SSD has no effect on performance because unlike a standard hard drive there is no
mechanical parts that need to move from area to area to read data. Data at any location on the drive
can be read at the same speed, because there are no moving parts.

So in a nutshell you are burning excess energy worrying about something that doesn't need worrying
about.

Kj

KJK555 wrote:
so the automatic defrag process will have minimum effect on the SSD's life span, in fact it may
improve the life span of the drive because temp files that are constantly reading and writing to disk
will be moved occasionally to a new area on the disk instead of wearing out one spot continuously.

Even that shouldn't be a problem, if I understand what I've read about SSDs. They are supposed to have "wear-leveling algorithms" that even out where files get written to, to avoid any one spot being worn down unusually prematurely compared to the rest of the drive.

Scott Radloff wrote:
The only real benefit that a solid state drive has over a traditional hard drive at present is durability.

Not sure if I'm just being pedantic, but one of the things that kills me is noise. A Mac Pro with four hard drives spinning is a little irritating. I used my friends iMac the other day. Whisper quiet.

Network 23,

OS X does not defragment files. Never. What it does do is write files to disk such that they never become fragmented in the first place.

This is a significant difference. In most circumstances, it means that defragmentation is not needed. On the other hand, it also means that there is no accommodation for defragmentation in those rarer cases where it might be needed.

Scott

Scott Radloff wrote:
OS X does not defragment files. Never. What it does do is write files to disk such that they never become fragmented in the first place.

It does both.

In addition to numerous citations around the Web of OS X defragmenting files under 20MB,
http://support.apple.com/kb/HT1375
says...

Mac OS X 10.3 Panther can also automatically defragment such slow-growing files. This process is sometimes known as "Hot-File-Adaptive-Clustering."

Unless you can show that Mac OS X has stopped doing what it did starting in Panther, Apple says it defragments.

Network 23,

Well, "never" may have been too strong, but I stand by my statement. OS X just doesn't "defragment" in the commonly accepted sense of the word.

First, it uses "delayed allocation" to reduce the amount- in many cases to zero- of fragmentation that ever occurs.

Second, it does use "adaptive hot-file clustering," whereby an elite class of the most frequently accessed files are written to the drive's "hot band." The limitation on size is <= 10 MBs (if I am not mistaken), and this does occur dynamically. Since this necessarily eliminate any fragmentation for these files, one could state that dynamic fragmentation is occurring. The amount of data we're talking about here is very small, however, so to classify this as generic "defagmentation" would be a stretch.

Third, there is one very limited case when a file will actually be rewritten. Several conditions must be met, the most important being that the file in question must have an allocation of over 8 extents. Since this still applies only to files <= 20 MBs, and given the other fragmentation-prevention measures in place, the conditions under which this occurs will be very, very rare. I will grant, however, that in the rare case that these conditions are all met, the file is indeed relocated to an unfagmented allocation when/if it is opened. Yes, this is dynamic defragmentation.

All this said, "defragmentation" is generally considered to be when a volume is scanned for fragmented file, and those files are all relocated to elimate all fragmentation. This does not occur in OS X.

Scott

Regarding performance on the SSD. I own the new 17" MacBook Pro with the 256GB SSD and it is incredible and faster than anything I have ever used. I first had the MacBook Pro with a 7200 RPM drive for a day but returned it for the SSD and it is VERY noticeably faster than what I experienced with the 7200 SATA drive.

My SSD boots up in 32 seconds and shuts down in literally 3 to 5 seconds. With Snow Leopard it says that will speed up by 2x on boot and 1.8x on shutdown so I can't wait to experience that with the SSD. I love the fact that I can boot up and shut down so quickly now. It makes it possible to grab those little windows of time to get some work done and not spend it all waiting on the computer.

I also love the battery life. Absolutely amazing. I have always carried my Windows laptop around plugged into outlets because I could never get more than an hour or two if I was lucky and didn't want to end up leaving with it not charged and needing it. With this MacBook Pro most of the time I am not plugged in and when I do plug in it only takes about an hour to be back at full battery charge even while I am using the computer. Absolutely amazing.

I have been converting all my Adobe suites over from Windows to PC because even though I have Parallels (great product) running Windows 7 on here in comparison to running them on Mac OSX it is so much better of an experience that it doesn't even make sense for me not to convert over.

The last thing I will say is that one of the main reasons I purchased it was for the antiglare screen so I could work outside and enjoy the sunshine without any issue of reflections. It performs better than I could have ever imagined.

So all in all this has been one of the BEST investments I have ever made. Absolutely an incredible product. I am now officially a PC that has converted to a MAC. Of course, my early days in computers started with the Apple IIe and later on in the mid '90s the MAC Performa, so it feels great to get back to my roots after Corp America dragged me into PC's. Ahhhhh deep refreshing breaths coming from me....