MBPro - ATP 8GB USB showing as 7.0GB?

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Mattk
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MBPro - ATP 8GB USB showing as 7.0GB?

Post by Mattk »

Why would an ATP Nano Dura AF8GUFNDNC being a 8GB SLC USB be showing as only 7.0GB in the Information System tab?

FW 5.1 (Feb 9 2021, build 14308) also shows the same.

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galfert
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Re: MBPro - ATP 8GB USB showing as 7.0GB?

Post by galfert »

Unfortunately many decades ago hard drive manufactures decided that it would be better to round off to 1000 instead of the proper 1024 for any given storage quantity. And this false advertising has become an industry standard now. This then results in:

8 GB = 8000 MB instead of the realistic 8192 MB.

Therefore 8000 MB is really 8000 / 1024 = 7.8 GB. So your 8 GB storage is not really as big as it seems. Then the 7.8 GB has a loss due to formatting. The formatting has overhead of its own and depending on how you format, the type of file system and the size of the blocks you choose (something is chosen regardless as there are defaults) means that you'll lose some space to the formatting. Typically this then means that you'll probably end up with around 7.4 GB of usable storage. Now comes some speculation on my part. It seems that the Meteobridge is doing some rounding and the 7.4 GB then becomes 7.0 GB despite their really being 7.4 GB. Interestingly though it doesn't seem to round when displaying the free storage of 6.8 GB.
Meteobridge RPI | GW1000

Mattk
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Re: MBPro - ATP 8GB USB showing as 7.0GB?

Post by Mattk »

Yes that is logical but something that had not previously stood out and never gave it a second thought either. What I now notice and attracted my attention is the capacity is now in Gb with FW 5.x anyway, checking some other units with various FW between 3.5 and 4.3, storage was shown in Mb.

All good, thanks for that.

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