the kopite 07:00 13 May 2005

Hi Guys I have two HD,s totaling 140 gb yet when I add them up this is what I get C: 24.3 D: 27.8 E: 25.2 F: 24.9 G: I get is 130.2gb when adding them up am I right ( maths was never my strong point lol ) and if so were has the rest gone thanks kopite

  Diodorus Siculus 07:07 13 May 2005

Yes, that is about right. When a disk if formatted some space is lost.

Fred Langa explains it well:

Hi Fred: Why is there a discrepancy between the size of a 120 Gb. hard disk and the size reported by Windows Pro that claims 111.8 Gb.? What has happened to the other 8.2 Gb.?

The explanation is that hard drive manufacturers calculate hard disk size in 'base 10' notation while Windows does the calculation in 'base 2' (binary) format. This is applicable, both the manufacturer and Windows are right, OK?

But I have read information about something different, for example: hard disk manufacturers use a 160 Gb. drive that has errors on it and sell it like a brand new 120 Gb., because in their line of products they don't have a 140 Gb. You can compare it with chip makers and their processors: you buy a 1800 Mhz. but with overclocking you maybe can reach 2000 Mhz. or more. They guarantee that the processor works well at 1800 Mhz.

Using the same example, can one access the other "good" parts of the remaining 40 Gb. that are hidden with special software or tools that people can't reach? What is the truth? Thanks in advance for your reply. ---Enrique Paff

All the factors you mention can come into play, Enrique, and we'll discuss them in a moment. But there's one more that has an even larger effect: Drives are sold by "raw" or unformatted capacity. When you partition and format a drive, some of the space on the drive is occupied by the partitioning and formatting data structures.

By analogy: think of a filing cabinet. As sold, it can hold a certain number of pages per drawer. But when you add hanging folders, the frames for the folders, index pages, and so on, you actually lose a little space, but can then organize and find your papers more easily. It's the same with hard drives: The partitioning and formatting takes up some space on the drive, but is necessary to organize and find your files.

Older drive formats (FAT, FAT16, the early Linux formats, etc), were created in the days when drives were tiny compared to today's. The older formats are not very efficient, and can waste a huge amount of space on a large drive. Those formats also can have severe, built-in limits to the size of the drives or partitions they can "see;" today's drives can simply be beyond the ability of these older formats to handle well.

Newer formats (FAT32, ext2, etc.) do better with larger drives; and some formats (NTFS, ext3, ReiserFS, etc.) were specifically designed with very large drives in mind. These latter formats help you to make the most of your disk space, with minimal wastage and no practical limits on disk or partition size. (Yes, there are limits--- e.g. 2 terabytes for NTFS--- but most of us won't reach them anytime soon. <g>)

More info on formatting and drive capacity:
click here
click here
click here

  Diodorus Siculus 07:09 13 May 2005

Next, there are indeed marketing factors, where base10 and base2 numbers get intermingled confusingly. You can even see this confusion in a simple Google definition search on the word "gigabyte:"

click here

Some of the sites say a gigabyte is "A billion bytes. A thousand megabytes." This is correct in what we might call "casual techspeak," but it is mathematically imprecise. Other sites say "2 to the 30th power (1,073,741,824) bytes.... one gigabyte is equal to 1,024 megabytes." This is the more precise definition. In fact, a purist would say it's the only "correct" answer. But again, in informal speech, many, many people round off and use the simpler definition. The problem comes when a drive maker labels a drive the casual-speech way, and you're expecting the mathematical way: Then, there'll be a discrepancy of 24MB per GB, which really adds up in the larger drive sizes. (There were even lawsuits about this a couple years back.) So, you have to know how a drive maker defines his terms before you trust the capacity numbers.

And then there are the sector-relocation areas. It's not at all unusual for a huge drive to have an uncorrectable manufacturing defect or three somewhere on its surface, so many drives ship with a low-level "remapping" tool that automatically substitutes a good location somewhere else on the disk for the bad location(s). Your software may know nothing of this remapping--- it can address the moved location by its original address, and the drive's firmware handles the translation to the new address. In this way, a few bad sectors don't cost you any net drive space; and your end-user software doesn't waste time trying to correct uncorrectable manufacturing defects (it never even sees the bad sectors).

I've never heard of a case where a sector-relocation area significantly affects a drive's total capacity. I suppose it could happen, but I think this is not a likely thing. The first two issues, though--- raw versus formatted capacity, and base10 versus base2--- are *huge* factors affecting how much usable space you end up with on any given drive.

You'd think drive size would be simple, wouldn't you? <g>

  Diodorus Siculus 07:15 13 May 2005

LangaList Std Edition 2005-04-21
click here

  the kopite 08:04 13 May 2005

Thank you Diodorus I just thought a loss of 9.8 gb excessive ? kopite

  Diodorus Siculus 08:09 13 May 2005

Not excessive.

  SEASHANTY 08:40 13 May 2005

Seagate information

Windows 137GB capacity barrier

click here

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