Newbie Question on HDD

G

giorgio

Member
It's really a basic and simple question, but I have these two hard disks
Memory - 1st Hard Disk
120GB KINGSTON HYPERX 3K SSD, SATA 6 Gb/s (upto 555MB/sR | 510MB/sW)
2nd Hard Disk
500GB WD SCORPIO BLACK WD5000BPKT, SATA 3 Gb/s, 16MB CACHE (7200 rpm)
Click to expand...
Why, when I see the properties, the first is 111GB and the second one 465GB? :)
 
vanthus

vanthus

Member Resting in Peace
That's normal,windows uses a different counting method, binary as opposed to decimal.With binary 1GB equals 1024 MB where the manufacturer uses decimal,1000 MB per 1GB,
120 GB shows as 111 GB.
500 GB shows as 465 GB
The way to work it out with a 500 GB drive for example is,
500,000,000,000 / (1024*1024*1024) = 465.66 GB
 
Last edited:
ubuysa

ubuysa

The BSOD Doctor
The binary numbering system isn't used in computing to be different or difficult, it's used because all computers are binary machines. Everything they do is based on 1 and 0 (or on and off if you like). So the binary numbering system is the natural way to number everything in computing, including hard disk capacity. Most computer users don't understand binary (and don't need to) so vendors usually quote hard disk space in decimal.

You might find the explanation of bytes, kilobytes, megabytes etc. here useful. Don't worry about binary numbering too much though, unless you're a techie you don't need to know anything about it... :)
 
vanthus

vanthus

Member Resting in Peace
Yeah,don't worry about it,that's why I said it's normal,and tried to give a short explanation. :)
 
vanthus

vanthus

Member Resting in Peace
ubuysa said:
Sorry Vanthus, I wasn't trying to step on your toes, I was just trying to help the OP understand. :)
Click to expand...
No worries,I agree with you,some things are better just being accepted without going into too much technical detail. :)
 
Outerarm

Outerarm

Well-known member
vanthus said:
That's normal,windows uses a different counting method, binary as opposed to decimal.With binary 1GB equals 1024 MB where the manufacturer uses decimal,1000 MB per 1GB,
120 GB shows as 111 GB.
500 GB shows as 465 GB
The way to work it out with a 500 GB drive for example is,
500,000,000,000 / (1024*1024*1024) = 465.66 GB
Click to expand...
I've always wondered why available disk space was always 8% to 10% lower than I was expecting based on the published size of the disk. Despite spending my whole working life in IT I never understood the reason... until now! Thanks!
 
G

giorgio

Member
When I was younger I attempted for 2 years in engineer university, so I know the different numerical system, but I always was a newbie for computers, so thank you very much for the short, but complete reply :)
 
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