Disk Defragmenter question: compacting files

[Ken Gardner]

I have a Disk Defragmenter question. When defragmenting a hard drive,
it sometimes reports that it is "compacting" files. Here are my
questions:

1. What exactly does this mean? For example, is the program reducing
the size of files by eliminating wasted space? Or does the program
mean something else, e.g. consolidating free space?

2. Do major third party defraggers, such as Diskeeper or PerfectDisk,
compact files in the first sense, i.e. by reducing the size of files
by eliminating wasted space?

Thanks
Ken

 

[Michael T]

http://computer.howstuffworks.com/question548.htm

 

[Ken Gardner]

http://computer.howstuffworks.com/question548.htm

Thanks. The problem is that the weblink talks about the Windows 98
defragger. My questions pertain to the XP defragger.

Ken

 

[André Gulliksen]

I have a Disk Defragmenter question. When defragmenting a hard drive,
it sometimes reports that it is "compacting" files. Here are my
questions:

1. What exactly does this mean? For example, is the program reducing
the size of files by eliminating wasted space? Or does the program
mean something else, e.g. consolidating free space?

Your last assumption is correct. Unfragmented files are moved for the sake
of consolidating free space.

2. Do major third party defraggers, such as Diskeeper or PerfectDisk,
compact files in the first sense, i.e. by reducing the size of files
by eliminating wasted space?

No.

 

[Stan Brown]

in microsoft.public.windowsxp.general:

http://computer.howstuffworks.com/question548.htm

It's a lovely article, but it doesn't answer his question.

1. "Compacting" means taking a file that was in fragments and
putting the fragments together sequentially. The wasted space
before and after is unchanged: it's whatever's left over at the end
of the last cluster of the file.

2. Sorry, I don't know. But I doubt it. The only ways to take a
file and make it smaller without losing inormation are

a. Reformat the disk in smaller clusters, so that the slack
space at the end of the last cluster per file is less, on average.
I'm sure those products don't do that, at least not without telling
you.

b. D some sort of compression, e.g. ZIPping. It's unlikely
those products do that either.

 

[JerryMouse]

2. Do major third party defraggers, such as Diskeeper or PerfectDisk,
compact files in the first sense, i.e. by reducing the size of files
by eliminating wasted space?

No. But NTFS can. See "Compressed" files, for example:

http://support.microsoft.com/default.aspx?scid=kb;en-us;307987

 

[Ken Gardner]

It's a lovely article, but it doesn't answer his question.

That's okay. It was a very interesting article in its own right,
especially its description about how some hard drives actually work,
as well as why files on the outside rings of the disk are read faster
than files on the inside rings. To make a long story short, it has to
do with some fancy math that, IIRC, goes all the way back to Galileo.

1. "Compacting" means taking a file that was in fragments and
putting the fragments together sequentially. The wasted space
before and after is unchanged: it's whatever's left over at the end
of the last cluster of the file.

Okay, this makes sense. "Compacting" = defragmenting the file. I
already knew that no more than one file could reside on the same
cluster -- which, incidentally, is a major reason why NFTS is a better
file system than FAT32 for large hard drives.

2. Sorry, I don't know. But I doubt it.

I do, too. In fact, in re-reading my own question, I may have
confused compacting with compressing (which hurts disk performance --
the very opposite of what a good disk defragmentation program is
supposed to do).

The only ways to take a
file and make it smaller without losing inormation are

a. Reformat the disk in smaller clusters, so that the slack
space at the end of the last cluster per file is less, on average.
I'm sure those products don't do that, at least not without telling
you.

Right, although the Partition Magic software does do this job.

b. D some sort of compression, e.g. ZIPping. It's unlikely
those products do that either.

Right, for the reason I mentioned above.

Thanks
Ken

 

[Al Dykes]

That's okay. It was a very interesting article in its own right,
especially its description about how some hard drives actually work,
as well as why files on the outside rings of the disk are read faster
than files on the inside rings. To make a long story short, it has to
do with some fancy math that, IIRC, goes all the way back to Galileo.



Okay, this makes sense. "Compacting" = defragmenting the file. I
already knew that no more than one file could reside on the same
cluster -- which, incidentally, is a major reason why NFTS is a better
file system than FAT32 for large hard drives.


I do, too. In fact, in re-reading my own question, I may have
confused compacting with compressing (which hurts disk performance --
the very opposite of what a good disk defragmentation program is
supposed to do).



Right, although the Partition Magic software does do this job.


Right, for the reason I mentioned above.

Thanks
Ken

NTFS file systems can put a "compression" property on any file or
folder (except things like pagefile and hibernate).

In Explorer;

right mouse click on a file or folder then

-> Properties/Advanced

Check "compress" and OK. Select all subfolders.

It may take awhile.

It makes sense to defrag after a major compression.

I've coompressed the entire C drive on countless machines in the day
when disk drives wern't as big as we wished. The only place where
this is discrecommded is for apps wthat update files in place, like
datbases. It'll work but it might be dog slow. It doesn't do anything
for MP3s or JPGs, but it doesn't hurt, either.

 

[NobodyMan]

I've coompressed the entire C drive on countless machines in the day
when disk drives wern't as big as we wished. The only place where
this is discrecommded is for apps wthat update files in place, like
datbases. It'll work but it might be dog slow. It doesn't do anything
for MP3s or JPGs, but it doesn't hurt, either.

Not always true. Most of the time, if your try to compress an MP3 or
JPG file (which are already compressed by their nature) you will end
up with a file a little bigger than before you started. So it does
hurt in the terms of trying to increase free drive space.