[dccski]

just talked to apple care technician and he said with apples they defrag every time you start up the computer. he said every so often shutdown and restart and it defrags itself. others say you need to. im so confused. and if you need to defrag what product. tech tools 4 looks good.

[bradoesch]

I know for sure the entire hard disk isn't defraged each time you startup. I think what the Apple tech meant was your RAM gets "defragged" (cleared and unfragmented) when you restart.
When you quit an app, it gives up its memory space for other programs. This process isn't 100% efficient and some memory can be lost.

[Patcarla]

Originally posted by dccski:
just talked to apple care technician and he said with apples they defrag every time you start up the computer. he said every so often shutdown and restart and it defrags itself. others say you need to. im so confused. and if you need to defrag what product. tech tools 4 looks good.

I just defragged my Tibooks which 3 months old..I used Drive 10 and I can tell you that the HD was fragmented...

[urrl5201]

Where can I get this Drive 10???

[Patcarla]

Originally posted by urrl5201:
Where can I get this Drive 10???

look here:
http://www.micromat.com/drive_10/dri...roduction.html

[gururafiki]

So there is DRIVE 10, Norton Utilities, and Tech Tools. Which one is better?

[iohead]

Originally posted by bradoesch:
I know for sure the entire hard disk isn't defraged each time you startup. I think what the Apple tech meant was your RAM gets "defragged" (cleared and unfragmented) when you restart.
When you quit an app, it gives up its memory space for other programs. This process isn't 100% efficient and some memory can be lost.

Neither the disk nor the RAM is defragged or cleared, etc.

Modern filesystems do not require defragmentation, because by design they avoid fragmentation to a great extent.

However, when you boot your Mac OS X machine, an "fsck" (file system consistency check) may be performed if one of the following conditions are met:

* The system was shut down ungracefully, and the filesystem has the "dirty" bit set.

* The filesystem has reached its threshold - the number of times it can go without needing an fsck.

-A

[drmbb2]

Originally posted by iohead:
Modern filesystems do not require defragmentation, because by design they avoid fragmentation to a great extent.

Of course, some might argue that HFS+ does not qualify as a "modern" file system, as it dates back to OS 8.1 which came out in, what, 1997!?! Many other file systems have made tremendous imporvements in the last 6 years, and in my experience, HFS+ under OS X is just as prone to fragmentation as it ever was under OS 8.x or 9.x - which, depending on the nature of your computer use, can be trivial to severe.

[craigthomas]

Get Disk Worrior instead.

[iohead]

Originally posted by drmbb2:
Of course, some might argue that HFS+ does not qualify as a "modern" file system, as it dates back to OS 8.1 which came out in, what, 1997!?! Many other file systems have made tremendous imporvements in the last 6 years, and in my experience, HFS+ under OS X is just as prone to fragmentation as it ever was under OS 8.x or 9.x - which, depending on the nature of your computer use, can be trivial to severe.

Well, honestly I don't know much about HFS+ specifically. As to whether it is "modern" or not - Linux ext2 has been around for *much* longer than since 1997, and you never have to worry about fragmentation with ext2. They do have a newer "ext3" now, but that's primarily ext2 + jouarnaling + some attributes. It'd be rather weird (but very much possible) that Apple's HFS+ is so much worse than, say, ext2.

Another thing the original poster could try (more so for reliability and faster recovery - not to do with fragmentation) is to turn journaling on (assuming you are using 10.2.2 or above).

Regards
-A

[bradoesch]

Originally posted by iohead:
Neither the disk nor the RAM is defragged or cleared, etc.

The RAM has to be cleared on a restart. How would the contents of the RAM stay intract without power? Please explain this further.

[iohead]

Originally posted by bradoesch:
The RAM has to be cleared on a restart. How would the contents of the RAM stay intract without power? Please explain this further.

When you start (or restart) a machine, the firmware will load the operating system (there might be multiple stage boot loaders, but they are all just programs) at a fixed location in memory. Then the loader will execute a JUMP to that fixed location and start running the code.

Initially, all memory is unallocated, and the kernel generally doesn't care about the contents of memory it hasn't allocated.

The only time "clearing" of memory comes into play is when a client is requesting a memory allocation (malloc(), say, there are many more kinds of memory allocation functions in the kernel), and the client specifically wants the memory zeroed out or something.

Unless I am missing something in your question, I don't see where the clearing or defragment of RAM at restart time comes into play.

A memory manager (in the kernel, or as an external server with many microkernels) would usually do things like the following:

* Keep track of what addresses are free
* Arrange/rearrange address chunks based on size, etc., to minimize fragmentation
* Write various "magic" numbers to memory that has been freed/allocated/used/unused etc., such as "0xbaddcafe", "0xdeadbeef" etc. This is to help the kernel and/or libraries figure out when things go wrong.

However, the above things are ongoing activities and happen all the time - not just at start time.

Regards
-A

[coolmacdude]

Originally posted by gururafiki:
So there is DRIVE 10, Norton Utilities, and Tech Tools. Which one is better?

Drive 10. Norton is a crappy piece of bloatware.

[bradoesch]

Originally posted by iohead:
When you start (or restart) a machine, the firmware will load the operating system (there might be multiple stage boot loaders, but they are all just programs) at a fixed location in memory. Then the loader will execute a JUMP to that fixed location and start running the code.

Initially, all memory is unallocated, and the kernel generally doesn't care about the contents of memory it hasn't allocated.

The only time "clearing" of memory comes into play is when a client is requesting a memory allocation (malloc(), say, there are many more kinds of memory allocation functions in the kernel), and the client specifically wants the memory zeroed out or something.

Unless I am missing something in your question, I don't see where the clearing or defragment of RAM at restart time comes into play.

A memory manager (in the kernel, or as an external server with many microkernels) would usually do things like the following:

* Keep track of what addresses are free
* Arrange/rearrange address chunks based on size, etc., to minimize fragmentation
* Write various "magic" numbers to memory that has been freed/allocated/used/unused etc., such as "0xbaddcafe", "0xdeadbeef" etc. This is to help the kernel and/or libraries figure out when things go wrong.

However, the above things are ongoing activities and happen all the time - not just at start time.

Regards
-A

I think we're talking about two different things here. You're saying what happens to the RAM when the computer boots, and I am trying to say that whatever is in RAM is lost when the computer restarts.
I was trying to answer dccski's initial question about defragging on startup. It sounds like he was talking about how the RAM always gets cleared when the computer is reset.
Hopefully we're understanding what we're saying now.

[iohead]

Originally posted by bradoesch:
I think we're talking about two different things here. You're saying what happens to the RAM when the computer boots, and I am trying to say that whatever is in RAM is lost when the computer restarts.
I was trying to answer dccski's initial question about defragging on startup. It sounds like he was talking about how the RAM always gets cleared when the computer is reset.
Hopefully we're understanding what we're saying now.

By "restart" do you mean a soft reboot, or do you mean awake from sleep?

-A

[bradoesch]

Originally posted by iohead:
By "restart" do you mean a soft reboot, or do you mean awake from sleep?

-A

I mean what the original poster is talking about, a restart, not awaking from sleep.

[nobitacu]

I'm waiting for Tech Tool 4 to come out. It'll be the best one out there once it's out. A must have.

Ming

[Patcarla]

Originally posted by nobitacu:
I'm waiting for Tech Tool 4 to come out. It'll be the best one out there once it's out. A must have.

Ming

I jus got Drive 10 and found that they give free Tech Tool 4 upgrade after drive 10 purchase.. Looking forward to get it..

[CheesePuff]

What the Apple technician meant was that every time you restart with OS X 10.2 and above, any new applications installed are prebinded. Before in 10.1 this never happended and you would have to do this in Terminal (sudo update_prebinding -root /) but now with 10.2 it will do it automatically.

[OSXFreak]

As far as I'm aware, there's not an OS on this earth that isn't immune from fragmentation unless it runs an auxillary defrag service, which OS X definitely doesn't.

On XP (sorry, dirty word), defragging a badly effected disk makes a HUGE difference to performance. So, if your disk is "chugging" to do relatively simple tasks, chances are you're badly fragged. And that has nothing to do with Quake.

[iohead]

Originally posted by CheesePuff:
What the Apple technician meant was that every time you restart with OS X 10.2 and above, any new applications installed are prebinded. Before in 10.1 this never happended and you would have to do this in Terminal (sudo update_prebinding -root /) but now with 10.2 it will do it automatically.

Prebinding has nothing to do with defragmentation. If this is indeed what the Apple tech said, then that's a pretty misleading way to put it IMO.

-A

[CheesePuff]

Originally posted by iohead:
Prebinding has nothing to do with defragmentation. If this is indeed what the Apple tech, then that's a pretty misleading way to put it IMO.

-A

Well the technician said that it is done every time you start-up and thats the only process that comes close to it.