bootable ext. USB SSD for backup

[Martin S. Weber]

On 03/16/17 20:56, Valeri Galtsev wrote:
>
> On Thu, March 16, 2017 2:46 pm, Matthias Apitz wrote:
 >> (...)
>> Mar 16 19:36:54 c720-r314251 kernel: da0: 953869MB (1953525164 512 byte
>> sectors)
>> Mar 16 19:36:54 c720-r314251 kernel: da0: quirks=0x2<NO_6_BYTE>
>>
>> Ofc it has not the promised 1 TB volume, just only 953869 MB, i.e. only
>> 1 Marketing-TB;
>
> It may have to do with counting by power of 10 instead of power of 2 (Not
> exactly correct, but close). Which remind me an old joke:
>
> Do you know the difference between junior programmer and senior programmer?
>
> Junior programmer faithfully thinks that one kilobyte is exactly 1000 bytes.
>
> Senior programmer faithfully thinks that one kilogram is exactly 1024 grams.
>

Well, there's a proper SI prefix for powers of two, which for your joke, 
Valeri, is "kibi" (2^10), and for Matthias is "Mibi", "Gibi" 
respectively "Tebi"; they are abbreviated as KiB, MiB, GiB and TiB, 
respectively (when applied to bytes). So the junior programmer is 
actually correct, and the senior programmer should know a kibigram has 
1024 grams.  It doesn't help that FreeBSD isn't using proper prefixes 
for printouts itself.

Toshiba says this thing has 1 TB, which is 10^12 bytes, which is (10^12) 
/ 512 512-byte units, or, in other words, 1953125000 512 byte units. 
Contrast that with the reported 1953525164 512 byte units the drive 
actually lets you access. Toshiba is clearly underselling the  disk.

/anal mode off