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Usb 3.0 Flash drive 16gb after formatting 14.6

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October 5, 2012 9:20:53 AM

just bought Transcend 16gb usb 3.0 flash drive formatted(NTFS/4096 bytes) it and as the title says its 14.7 gb now ill understand if its a normal behaviour after formatting,just wondering if its common case for every flash drive?
a b G Storage
October 5, 2012 9:48:14 AM

For manufacturers a GB is 1 000 000 000 bytes, while a true GB is 1024^3 bytes. It's a common advertising practice.

So it's easy to calculate that:
16 000 000 000 / 1024^3 ~= 14,9 GB.
October 5, 2012 12:09:13 PM

thx
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a b G Storage
October 5, 2012 1:20:26 PM

Welcome to the world of formatted capacities. 14.6 sounds about for a NTFS formatted 16gb drive. You could save a little space by formatting it FAT32, but you of course have the limitations of FAT32, like maximum individual file size of 4GB, and you'll have a 32kb sector size which creates a lot of slack space if you have a high number of files, but sometimes it's a trade worth having.
October 5, 2012 8:09:25 PM

mavroxur said:
Welcome to the world of formatted capacities. 14.6 sounds about for a NTFS formatted 16gb drive. You could save a little space by formatting it FAT32, but you of course have the limitations of FAT32, like maximum individual file size of 4GB, and you'll have a 32kb sector size which creates a lot of slack space if you have a high number of files, but sometimes it's a trade worth having.

As soon as i bought Flash i connected it to my laptop tried to copy two 7 gb files but i had a message that informed me that the file is too big,that was disappointing cos i though that using flash drive is a piece of cake anyway i googled my problem and yea i found out that it can be formatted.im mostly going to use this fd for copying big files from laptop which is almost full to my pc these files are iso 7 gb and i cant copy them to simple dvd so this fd is great and fast way to do it(not related to my main question>i also bought usb to usb cable tried to glue laptop and pc that is working only in safe mode due to some problem but that cable didnt work maybe safe mode causing this prob,before that i tried Dual layer dvd to save my huge music programs but i bought not Verbatim DL dvd but cheap and i have error and my dvd drive cant burn it correctly at least Flash Drive works fine )
a b G Storage
October 7, 2012 4:12:10 PM

cska said:
As soon as i bought Flash i connected it to my laptop tried to copy two 7 gb files but i had a message that informed me that the file is too big,that was disappointing cos i though that using flash drive is a piece of cake anyway i googled my problem and yea i found out that it can be formatted.im mostly going to use this fd for copying big files from laptop which is almost full to my pc these files are iso 7 gb and i cant copy them to simple dvd so this fd is great and fast way to do it(not related to my main question>i also bought usb to usb cable tried to glue laptop and pc that is working only in safe mode due to some problem but that cable didnt work maybe safe mode causing this prob,before that i tried Dual layer dvd to save my huge music programs but i bought not Verbatim DL dvd but cheap and i have error and my dvd drive cant burn it correctly at least Flash Drive works fine )




You'll get the "file too large" message when copying a 7GB file if the target drive is formatted FAT32. You'll need to format it to NTFS to copy individual files > 4GB.
October 8, 2012 8:43:36 AM

Quote:
Yes it is a common case. 16 gb exactly means 14.7 gb. As in real if you will count 1gb =1024^3 bytes not 1000^3 bytes.

Fanks J
October 8, 2012 8:44:23 AM

mavroxur said:
You'll get the "file too large" message when copying a 7GB file if the target drive is formatted FAT32. You'll need to format it to NTFS to copy individual files > 4GB.

got it,thx
October 10, 2012 8:17:16 AM

1 more thing what about allocation unit size during formatting :starts from smallest 512bytes>1024>2048>4096 (current setting)>8192>16kbytes>32>64kbytes.what these do and whats the best option performance-wise
a b G Storage
October 10, 2012 4:45:47 PM

An allocation unit can be thought of as a "chunk" of storage space. When a file is written, it will actually consume a multiple of your allocation unit size. This can help or hurt, depending on how it's utilized. While using a small sector size may cut down on slack space (especially with a drive containing thousands of files), disk IO will suffer slightly, because the drive and OS will have more allocation units to manage, which will increase the number of times the MFT / FAT has to be accessed.


Here's basically how allocation units and slack space relate -

E.g. if your allocation unit size is 32kb....

A 2kb text file will consume 32kb on the disk (the remainder is referred to as slack space)

A 32kb text file will consume 32kb (exactly one allocation unit)

A 33kb text file will consume 64kb of disk space (since it is more than one unit)


This comes more into play with hard drives where tens / hundreds of thousands of files reside. On such a relatively small drive, that sounds like it'll likely just have a few large files on it, just set the allocation unit size to 32kb and move on.
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