bootable ext. USB SSD for backup

[Valeri Galtsev]

On Thu, March 16, 2017 3:11 pm, Martin S. Weber wrote:
> 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),

I know, I know. The joke was meant to be consumed orally, not in a written
form. And it is so old that at the time I've heard it for the first time,
there were no Ki- Mi- prefixes (and we didn't dream about Gi then). Or
probably I was so ignorant then...

Valeri

> 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
>
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++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
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