Compressed HDD?

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CeeBee

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Hi guys, perhaps 1 of u in the know can provide some enlightenment... :)
A mate of mine insists on compressing his hard drives (even the c: drv)
So now my question is... is that a wise decision?
I am dead set against doing that, besides I don't have space issues... most of the time..., so I don't see the point.
My reasoning (!) says that the only benefit u get from compressing the HDD is to win a few megs of space, so if u have more than enough free space on HDD, then whytf do it?
Doesn't compressing the hdd make the system slower, especially Windows, coz before Win can use a file, it has to decompress it first?
Or can Win just use the files compressed as is?
I just can't help wonder, if it is such a good idea, howcome Win doesn't do it automatically, or remind u regularly to do it????
I don't get why he pays a crap load of munny for a fast machine, and then go 'slow' it down by compressing the HDDs (including windows/c: AND games).
So what's the verdict :confused:
 
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with hdd being so cheap, i would not suggest doing this

is he still running 98?

dont think windows xp can compress a drive

dont do it though, does not sound good to me
 
It definitely has performance implications, I'm just not sure how severe they are.
 
he's got AMD 64x2 5400, Win XP SP2, and two big HDDs, more than enough space free. So why do it??? F*k knows!:sick:
Sure he must have heard some reasoning for it somwhere, coz thats the first thing he does after install, I just cant figure out the logic....
 
Yeh it slows down the system, will be dumb to do it if there's enough space
 
It all depends, it could even speed the system up. What is faster, reading a chunk of uncompressed data, or 1/3 of the data and then decompress? Same applies for writing data. One factor affecting the speed is the size and the defragmentation of the files on the HDD. If it means a lot of head movements then working with compressed files/folder will definitely be faster. And yes, xp can compress, on a folder by folder basis, possiblye even individual files. On my machine, all Windows updates are in a compressed folder and I did not set that up in that way.
Programs typically compress to about 50% of original files size, but data may compress down to 30, even 20 percent. This means that there may be considerably less disk when working with compressed data/drives.
However, compressing the whole c: drive or the windows folder may just give you grief when the OS may need to be re-installed.
 
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Since the old HDD is effectively a mechanical turntable, it is the bottleneck in any system. Compressing data means less reads / writes to get stuff from and to the HDD, so it can improve performance ever so slightly, but it also involves creating temporary file read/writed during the process, esp. with larger files, so there goes the performance gain. Unless you are desperate for space, don't do it. It also doesn't benefit most (already compressed) media files, like MP3, etc (although it tries). And if your HDD corrupts, man it corrupts well. If you have loads of files with lotsa white space in them in certain folders, then sure, compress those folders, otherwise... a waste of time. And of course, CPU usage goes up with compression.
 
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but it also involves creating temporary file read/writed during the process
Click to expand...

The compression method used for on-the-fly (de)compression is not like Winzip, 7-zip, etc. It uses a method called RLL (Run Length Limited), which uses an in-memory buffer but no temporary disk files.
 
Back in the days of Win93SE one could essentially get upto 30% more space on a HDD, that's 30GB per 100GB space, which is a LOT. Compresssions really only compress what can be compresses, but since about 60% of the HDD is fille with document type files, you'll be able to free up some space easily. Windows XP also support it, and it's much more stable than Win98's FAT32 compression. You need to run NTFS though, which most systems do these days by default.
 
If the machine is accessing tons and tons of tiny files the compressed drive is hektually faster if you're not wanting to use the memory consumed for anything else.

But ... my main problem with compressed drives is that you can loose a heck of a lot of data if one of the compressed file directories gets stored on a bad sector, the entire compressed disk can be lost.
 
risingtide said:
The compression method used for on-the-fly (de)compression is not like Winzip, 7-zip, etc. It uses a method called RLL (Run Length Limited), which uses an in-memory buffer but no temporary disk files.
Click to expand...

Just wondering... how does it handle files in excess of a gig for example?
 
How about someone find the time to do throughput testing for us?
That would be interesting...
Maybe using nero or other tool.
 
I haven't compressed my drive since the last 200mb drive I owned. Used a DOS program to do the compression, it left one 200mb file on the drive, and it worked great. In Windows 3.1 it showed 380mb total drive space! Then one day that single file got corrupt and I lost everything :sick: Since then I've just bought new drives when I needed space... no hassles :)
 
A large file in excess of a gig is handled sequentially. The program reading the file will ask for a portion of the file from starting point A, N bytes long, and the decompression tool uses the directory to locate the corresponding compressed bits and gets them and decompresses them and hands them to the program in a sequential format called a stream.
 
Hmmm, won't it also make your data harder to recover if your hard drive fails? I think I remember reading that somewhere, don't ask me if it's true or not :confused:
 
It is not recommeded to compress your bootable partition. You will run into trouble once you need to recover the data by using it as a secoundary drive in a other system.
 
Hmmm, won't it also make your data harder to recover if your hard drive fails?
Click to expand...

I would consider recovery of data off a compressed harddrive as near impossible. As has been posted by someone, all files and the directory structure reside in a disk single file and it is the OS's compression software which manages all that and makes it appear 'normal'. If one loses that single file for whatever reason, the whole HD content is gone. If one loses part of it, then the loss is probably so big (the data being compressed) that the resulting file will be unusable.
Even on a normal HD recovery of content is difficult and there will always be the question whether one can trust what was recovered.
However, in todays' world of HD capacities and prices, and being able to have any number of (external) disks, a HD failure should not be catastrophic anymore. Where is your backup?
Every month I make a file copy of my harddisks to an external drive, using a suitable backup program which compresses the data.
 
cool, thanx for the comments guys.
So, while it looks like there might be 'some' gains to compressing the HDDs, apart from mainly saving a bit of space (which is clearly not neaded, when lotsa free space is available)... it sounds like, on a pc being used mainly for gaming, and with other valuable files (not backed up), it is not to be recommended.
 
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