why is it when I buy a hard drive does it come with less gigs then the box says?

Question

like if you buy a 160gb hd does it only have 152gb?

Answer 1

Hi

Advertised vs. Actual

Here is a quick reference to show the amount that the actual values differ compared to the advertised for each common referenced value:

Megabyte Difference = 48,576 Bytes
Gigabyte Difference = 73,741,824 Bytes
Terabyte Difference = 99,511,627,776 Bytes
Based on this, for each Gigabyte that a drive manufacturer claims, they are over reporting the amount of disk space by 73,741,824 Bytes or roughly 70.3 MB of disk space. So, if a manufacturer advertises an 80 GB (80 billion bytes) hard drive, the actual disk space is around 74.5 GB of space, roughly 7% less than what they advertise.

Now, this isn't true for all the drives and storage media on the market. This is where consumers have to be careful. Most hard drives are reported based on the advertised values where a Gigabyte is one billion bytes. On the other hand, most flash media storage is based around the actual memory amounts. So a 512MB memory card has exactly 512 MB of data capacity, but this leads to the next area of reported space.

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Also

Formatted vs. Unformatted

In order for any type of storage device to be functional, there must be some method for the computer to know which bits stored on it relate to the specific files. This is where formatting of a drive comes in. The types of drive formats can vary depending on the computer but some of the more common ones are FAT16, FAT32 and NTFS. In each of these formatting schemes, a portion of the storage space is allocated so that the data on the drive can be catalogued enabling the computer or other device to properly read and write the data to the drive.

This means that when a drive is formatted, the functional storage space of the drive will be less than its unformatted capacity. The amount by which the space is reduced will vary depending upon the type of formatting used for the drive and also the amount and size of the various files on the system. Since it does vary, it is impossible for the manufacturers to quote the formatted size. This problem is most frequently encountered with flash media storage over larger capacity hard drives.

Hope this helps understanding..

Answer 2

The first reason behind this might be the way we do calculation of capacity,
1 Byte = 8bit
1KB = 1024Byte but normally 1000 means Kilo
1MB = 1024 KB = 1024*1024 Byte = 1024*1024*8 bit
But we calculate like 1MB = 1000 KB = 1000*1000 B = 1000*1000*8 bit
so this is how we calculate and what is actual

another reason might be like in case of flash drives (USB drives) some storage is used to put format information

Every disk needs some kind of format like FAT, FAT32, NTFS.
To store this information on disk we need some space.
For this reason if you purchase a 1GB flash drive it can not store 1GB of data, it will always store less than that because some part of the disk is already being used.

Answer 3

There are two reasons.
The first is that years ago disk manufacturers decided that they would call a million bytes a gigabyte rather than the real number of bytes to make their disks seem bigger. When they changed, disks were small enough that the difference was not very noticeable but as disks sizes increase the difference between claimed and actual size gets larger.
The second reason is that formating the disk uses some of the space. Different disk formats will give slightly different amounts of free space.

Answer 4

Two reasons:

1) Hard disk manufacturers use 1MB = 1000KB, 1GB=1000MB math. If you read the box carefully, it will say so somewhere. Your computer, on the other hand, uses 1MB=1024KB, 1GB=1024MB math. This is more true sense of MB and GB as it is in the power of 2 format. The hard disk manufacturers started using different conventions somewhere in the late 80s to make their drive appear larger.

2) When you format the disk in your computer using an operating system, it actually uses anywhere from 5 to 10% of the total space to store miscellaneous information such as file names, partition information, and some redundancy for error corrections. What's available to you is less than the physical capacity of the disk.

Answer 5

Actually, the operating system and such files usually take several gigs of space, and therefore you do not have a full "160 Gigabytes". Similarly, when you buy an iPod (for example, a "4-gig" or "8-gig"), you do not have 4 or 8 gigs of USABLE space because the iPod's operating system takes some of the space (usually a negligible amount, though).

Answer 6

imagine buying a book with all blank pages....

The table of contents and the index takes up some "useable" pages of the book

basicly the same thing..

So to "define" where pages are, and how large they are among other things... It gives each one a page number and remembers exactly where on the disk surface that page number lives.
This way the computer OS can look up information and know where on the disk that information lives.

Very much like the afore mentioned table of contents.

Answer 7

You drive is 160gb, but what you have to understand is when you format it you have to put files on the HD so the operating system can access and use it.

Answer 8

The Xbox 360 120GB demanding force incorporates a knowledge move kit to completely migrate all of your saved files out of your 20GB HDD on your 120GB HDD. It comes preloaded with large HD pastime demos, video clips, and an collection of Xbox stay Arcade pastime trials.

Answer 9

This often happens with devices that can hold files.

Well, I'm not quite sure why. But I do have an idea.

I think it's because there are "technical" stuff. Maybe the stuff that are needed to make your device work properly also need space. It's just an educated guess so I'm not quite sure.

Also, it might just be because they round 'em up. It's a great marketing strategy too.

Answer 10

It is due to the fact that the HDD is formatted to a certain format and formatting is eating a little of your space..Think of formatting as putting ruling in your papers...It consumes a part of you paper space right?then thats how it works...