mini micro sd cards

gudii9
gudii9 used Ask the Experts™
on
i bought two 128gb mini mocro sd card one from sandisc other from patriot

when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for sandisc card

when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for patriot card

i wonder why 128gb they do not show
also why both show different?

any place i can put price alerts to get deals email to my gmail
please advise
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Jackie Man IT Manager
Top Expert 2010

Commented:
when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for sandisc card

when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for patriot card

You do not have a problem, This is a classic marketing con trick.

The marketing people use kilo as 1000, mega as 1,000,000 and giga as 1000,000,000

A Gibabyte proper is 1024*1024*1024 bytes.

A Gigabyte in marketing is 1000*1000*1000

Thus they say 128,000,000,0000 bytes as 128 gigabytes.

Your computer works in proper gigabytes, so

128,000,000,0000 / (1024*1024*1024) = approx 119 (real) gigabytes.

Source: https://forums.digitalspy.com/discussion/2116374/why-does-my-128gb-micro-sd-card
Jackie Man IT Manager
Top Expert 2010

Commented:
any place i can put price alerts to get deals email to my gmail

Which online merchants you are referring to?
nociSoftware Engineer
Distinguished Expert 2018

Commented:
This is NOT a classic marketing trick......
SI (Systeme International)   Unit specifies the multipliers for units
1000 kan be abreviated to kilo (one thouasand)
1'000'000  can be replaces with M (Mega)
1.00.000.000 can be replaced  with G (Giga)

ICT people hijacked this by saying 1000 is more or less equal to 1024.... (which it is NOT).
For Units of information another multiplier has been defined
Ki (1024)                      (kibi)
Mi  (1024*1024)           (Mebi)
Gi (1024*1024*1024)   (Gibi)

So
You Expect 128 Gib, the box says 128GB
the 128GB = 128 * 1000 * 1000 * 1000 =  128.000.000.000
You computer divides by 1024  and calculates 128.000.000.000 / 1024 / 1024 / 1024 =119GiB,
But tells 119GB   (which actualy should have been 119 GiB)

(note gb means nothing at all: g is no abbreviating for a multiplier) and b = bits.   and 8 bits go into 1 Byte
als one order of a magnitude difference.

Another hint why this is not (Hard)disk manufacturers gone wrong...
the need to specify stull in parts of milimeters... (which is 1/1000 * meter) or micrometers (1/1000 of a milli meter).
Those are NOT 1/1024 etc. changing the multipliers would yield non-working devices when dealing with micrometers.
With chips this needs to work out to nanometer scale.

https://en.wikipedia.org/wiki/International_System_of_Units
https://en.wikipedia.org/wiki/Mebibyte
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Author

Commented:
so why kingston shows 119 gb where as other card only shows 117 gb

Which online merchants you are referring to?
any online site is ok as long as i get good deal and good product.
i purchased one from ebay but it did not work at all earlier
Top Expert 2013

Commented:
>>  i purchased one from ebay but it did not work at all earlier   <<  that's a risk you have, but you can return it for free, no?
i try to avoid bying from ebay as i can ! i try Always to use well known companies

and different ram cards may have a different use of the ram, so there can be (small) differences in their size, but usually windows shows less size than the product advertises  for all harddisks, ssd, and m2 drives
Software Engineer
Distinguished Expert 2018
Commented:
In the Question both are mentioned to be "119gb" for what it's worth:
when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for sandisc card

when i insert card to laptop to check size by right clicking on it and proprties shows 119gb for patriot card

Then there is a place where marketting might be involved namely to sell a 125GB disk as a 128GB.
rounded to a "more familiar size...")

More important are the SD's usable....
are both containing actual 128GB of data block..., some simple formatting (not FAT) and then fsck/chkdsk the drive (should yield no errors)
also SD / flash card testers could be used.
Due to the amount of money involved and the ease of getting equipment to tell the wrong size, one needs to verify for forgeries.
(that map f.e. 128GB onto just 1 GB) so writing beyond the 1GB mark should reveal this. NTFS, Ext* and other large filesystems use distributed structures that would reveal damage on such drives. (FAT will not show this).


BTW, Formatted size is always smaller than unformatted size as the filesystem administration also takes some space. (FAT has is all over the place), others have it in several places on disk.
so be sure to compare the same quantities....
(Some Flash devices might have slightly more data storage so a few defects can be discarded as "badblocks" while still fulfilling the promiss of the advertised storage.)
Some good quality versions have even more data available and will replace "bad blocks" without the user noticing less storage. (kingston has a line of sticks that report 16GB that actualy have 20-32GB internally) and only expose 16GB to the enduser.

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