missing hardrive space

junglequestions

bought 300gb seagate, set-up external
now missing 21GB!!! its only saying 279GB on mycomputer!!
looked at it in computer management and all seems fine - where's the 21GB gone??

Creamy Goodness

manufacturers advertise drives as being 1gig equals 1000 megabytes.
we all know in the computing world everything is done in the base of 2, so in fact a gigabyte is not 1000 megabytes but it's 1024megabytes.

so infact a 300gig hard drive is really only roughly 292 gigabytes.

this is where 7gig's has gone, but i'm unsure as to where the other 14gig's has gone.

nobodythere

Maybe the size of the partitioned hard drive is not the full drive.

Maybe they just advertised it as more than it was. What does it say on the actual drive itself with regards to size?


Also I've a feeling that windows doesn't count the FAT when it totals free space, so the bigger the hard drive and more files on it the more effect it would have

junglequestions

thank you,
i wonder where that 14GB went mmmm
i downloaded a programe from seagates website and it automatically set the partition up for me - i wonder if that messed up!

steviec

The conversion loss is more than that I think, because one megabyte is 1024 kilobytes and 1 kilobyte is 1024 bytes.

1 Gig advertised = 1,000,000,000 bytes
1 real Gigabyte = 1024 * 1024 * 1024 bytes

It's too late at night for me to do the maths...

Laguna

Well my 120gb HDD has only ever shown up as having 110gb, I hate the way they can advertise it as 120gb even though it's not due to their 'conversions'.

michaelpwilson

Hard drive manufacturers commonly use the conversion rate of 1,000,000,000 (one American billion) bytes to each gigabyte.

In computer land, however, measurements of capacity etc. are often calculated using base 2. The details aren't relevant to your question, but what this boils down to is the following:

1 Kilobyte = 1,024 bytes
1 Megabyte = 1,024 Kilobytes = 1,048,576 bytes
1 Gigabyte = 1,024 Megabytes = 1,048,576 Kilobytes = 1,073,741,824 bytes.

Using the American definition of billion, this means that each _true_ gigabyte comprises of 1.073741824 billion bytes. This means that a true 300 gigabyte drive would hold 322.1225472 billion bytes. If your drive had this capacity, Windows would report it (correctly) as being a 300 gigabyte drive.

However, as I said above, hard drive manufacturers don't use the above figure for a gigabyte. They calculate a gigabyte as being one billion bytes, which is technically incorrect. To them, 300 “gigabytes” equals 300 billion bytes.

Now let's convert this 300 billion bytes figure to a _true_ gigabyte figure.

300 billion bytes = 300,000,000,000 bytes.
300,000,000,000 bytes equals 292,968,750 kilobytes (dividing by 1024).
292,968,750 kilobytes equals 286,102.2949 megabytes (dividing by 1024).
286,102.2949 megabytes equals 279.397 gigabytes (again, dividing by 1024).

Therefore, Windows will report your 300 “gigabyte” drive as having a capacity of 279 gigabytes. You aren’t “missing” any space; you just didn’t have it to begin with.

Hope this helps.

Michael

P.S. I think the above calculations are correct, I apologise in advance for any mistakes!

nobodythere

Nicely calculated for 4am my friend

unkel

michaelpwilson wrote:

300 billion bytes = 300,000,000,000 bytes.
300,000,000,000 bytes equals 292,968,750 kilobytes (dividing by 1024).
292,968,750 kilobytes equals 286,102.2949 megabytes (dividing by 1024).
286,102.2949 megabytes equals 279.397 gigabytes (again, dividing by 1024)

Spot on Michael. Somebody is wide awake at 4am

calex71

space will be used in the formatting of the drive also

zuma

calex71 wrote:

space will be used in the formatting of the drive also

Only a very small amount.

Ive viewed NTFS drives under Win98 using an NTFS viewer and have seen(in my own 300/279GB drive) that the NTFS takes mabye 100MB at most.

The formatting takes only a small fraction of space.

The Binary(O.S.) and Decimal(H.D.D.) systems will really start to piss off people when we get into the TeraByte range...remember it was less than 10 years ago when a 1GB drive was about as extravegant as 1TB drives are today!

junglequestions

cool,
thank you very much, lucky i got the 300GB then and not the 250!

bloody laptop is about to giveup on me, will have to make a complete backup and do a reinstall.