You are here

Hard Drive Space

Rob Grauert's picture
Last seen: 1 year 7 months ago
Joined: 02/16/2008 - 10:47pm

I'm just curious...does anyone know why hard drives never have as much space as they claim? For example, i just got a 500GB LaCie today and it's capacity is only 465.76GB and my 750GB drive is only 698.32GB. It's not even close.

shippocaio's picture
Last seen: 7 years 2 months ago
Joined: 06/12/2008 - 7:24pm

I guess everybody has this problem.

This happens mainly becouse the hardrive already come with programs and files in it. For a example, My Operacional System occupies 8 to 10 GB, i think. So, instead of having 500GB free, i have 490GB.

Coreece's picture
Last seen: 8 years 3 weeks ago
Joined: 08/08/2007 - 7:56pm

>does anyone know why hard drives never have as much space as they claim?

Simply put, its a marketing ploy but not actually a lie.

A "500 GB" hard drive actually has 500,105,216,000 bytes of space. This is the actual size of the Hard drive calculated using the decimal system. However, typical operating systems use binary to calculate space. These methods are different thus giving different calculations.

Confusing, I know....but you can go to sleep tonight knowing that you're not really being skrewd. : )

Ken's picture
Last seen: 8 years 7 months ago
Joined: 01/12/2007 - 10:54am

Well, actually the space thief is the formatting. The raw unformatted space might be 500 GB, but each cylinder of each surface of the drive is divided into sectors. In the old days, 32 sectors was typical (sometimes 33, with the 33rd being a "spare" sector in case a surface defect was discovered while formatting). Not sure how many sectors is common now. But formatting puts a recognizable pattern at the start of each sector. That takes up space. You also need a file allocation table (or table of contents) to tell the O.S. what parts of the drive are available, and where to find the parts of specific files. And that takes up a lot of space.

(DISCLAIMER: Its been a LONG time since I was working with drive hardware and drivers, so some of the above might no longer apply.)


brandon0409's picture
Last seen: 9 years 3 months ago
Joined: 05/31/2006 - 12:21pm

Actually Coreece was clostest in the description. Formatting really has nothing to do with it. Everything is based on a blank slate. Formatting files use the available HDD space.

500,105,216,000 bytes worth of space on a drive. But because of the binary system 1-2-4-8-16-32-64-128-256-512-1024.

1 KB is actually 1,024 bytes.
1 MB = 1,024 KB
1 GB = 1,024 GB

So everything is based on this number

You must divide 500,105,216,000 by 1024 = 488,384,000 KB
488,384,000 KB /1024 = 476,937.5 MB
476,937.5 MB / 1024 = 465.76 GB

465.76 GB; I believe this is the number that registers when you install the harddrive. And that is why.

Formatting has nothing to do with it.

EarlC's picture
Last seen: 1 year 4 months ago
Joined: 10/15/2008 - 1:15am
Plus Member Moderator

My advice, FWIW, don't sweat the small stuff, like differences in rating and actual capacity. In years gone by there were significant and noteable differences between the two, and many such claims constituted a rip-off, or outright lies.

Today's HDs, however, give so much value, and so long as the general claims for capacity are "close enough" what difference does it make. People shouldn't "crowd" their HDs to the extent that differences in claimed capacity and actual come into play. If you are THAT close to having a full HD, it is cheap enough, and better as a rule, to add another log to the fire.

Anybody who has been doing video for any length of time has acquired a bounty of HDs in various capacities and formats and capabilities. I'd dare say that comparing capacity claims and actuals has been far from their primary concerns over quality, speed, and manufacturer warranties. Being redundant here, I have to say that overall with today's HDs actual capacity as it relates to any single given project is not mission critical.