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Jeff Troiano · June 12th, 2003, 10:56 PM

If I have 2 - 120 gig hard drives configured in a RAID 0 to make 1 - 240 gig hard drive. Now mind you there is no operating system on this drive, this is the sencondary drive, when looking under my computer it states that the drive is 224 gigs, where does that 16 gigs of space all of a sudden dissapear too? Been looking under the desk, behind the monitor, just can't seem to find where I might have dropped it at.

Jeff Troiano

Christopher Go · June 13th, 2003, 12:59 AM

Did you search between the cracks in the couch? In all seriousness the size discrepancies you're seeing is normal and is a result of a number of factors.

One is marketing and a difference between the way hard drive manufacturers advertise storage space versus the way the computer and OS does it. Each has their own definition of what a kilobyte, megabyte, and gigabyte is. While the rest of the computing world is on the base-two numbering system, which gives us 1024 bytes per kilobyte (or thereabouts if you want to be strict), hard disk manufacturers are on the base-ten system: 1000 bytes only to each kilobyte. That's why Windows will see a number that's slightly off when compared with what's advertised on your hard drive box. If you're wondering how the hard drive manufacturers get away with this its essentially because they lack regulations in the industry in this regard. If you think about it this is true of speaker monitors too and a whole host of other things...

An additional factor is the way the file system is mapped out on the drive, something that becomes more apparent with more hard drive space (NTFS versus FAT16 for example; NTFS is more efficient).

Finally, another siginficant factor is the stripe size of your RAID array. I'm not sure about your particular Serial ATA controller but you may have noticed you can customize which block size to choose. I think the default is normally 64. This is a contested area of computing for enthusiasts; some say one size is better for performance whereas another is better for storage. If not mistaken some implementations of RAID also reserve storage for itself in order to accomplish various kinds of RAID arrays.

In each case the drive differences are more salient and more apparent when you get higher in storage size. Your ~240GB is a good example of this. So no, you didn't necessarily lose GB but lots of it was already accounted for before you started.

June 12th, 2003, 10:56 PM	#1
Jeff Troiano Major Player Join Date: May 2003 Location: Nashville TN Posts: 480	Another PC Tech Question If I have 2 - 120 gig hard drives configured in a RAID 0 to make 1 - 240 gig hard drive. Now mind you there is no operating system on this drive, this is the sencondary drive, when looking under my computer it states that the drive is 224 gigs, where does that 16 gigs of space all of a sudden dissapear too? Been looking under the desk, behind the monitor, just can't seem to find where I might have dropped it at. Jeff Troiano

June 13th, 2003, 12:59 AM	#2
Christopher Go Major Player Join Date: Nov 2002 Location: Honolulu, HI Posts: 429	Did you search between the cracks in the couch? In all seriousness the size discrepancies you're seeing is normal and is a result of a number of factors. One is marketing and a difference between the way hard drive manufacturers advertise storage space versus the way the computer and OS does it. Each has their own definition of what a kilobyte, megabyte, and gigabyte is. While the rest of the computing world is on the base-two numbering system, which gives us 1024 bytes per kilobyte (or thereabouts if you want to be strict), hard disk manufacturers are on the base-ten system: 1000 bytes only to each kilobyte. That's why Windows will see a number that's slightly off when compared with what's advertised on your hard drive box. If you're wondering how the hard drive manufacturers get away with this its essentially because they lack regulations in the industry in this regard. If you think about it this is true of speaker monitors too and a whole host of other things... An additional factor is the way the file system is mapped out on the drive, something that becomes more apparent with more hard drive space (NTFS versus FAT16 for example; NTFS is more efficient). Finally, another siginficant factor is the stripe size of your RAID array. I'm not sure about your particular Serial ATA controller but you may have noticed you can customize which block size to choose. I think the default is normally 64. This is a contested area of computing for enthusiasts; some say one size is better for performance whereas another is better for storage. If not mistaken some implementations of RAID also reserve storage for itself in order to accomplish various kinds of RAID arrays. In each case the drive differences are more salient and more apparent when you get higher in storage size. Your ~240GB is a good example of this. So no, you didn't necessarily lose GB but lots of it was already accounted for before you started.