[systemd-devel] [ANNOUNCE] systemd 210

Colin Guthrie gmane at colin.guthr.ie
Wed Feb 26 04:30:21 PST 2014

'Twas brillig, and Lennart Poettering at 25/02/14 13:29 did gyre and gimble:
> On Tue, 25.02.14 13:05, Colin Guthrie (gmane at colin.guthr.ie) wrote:
>> 'Twas brillig, and Lennart Poettering at 24/02/14 22:08 did gyre and gimble:
>>>         * systemd will now understand the usual M, K, G, T suffixes
>>>           according to SI conventions (i.e. to the base 1000) when
>>>           referring to throughput and hardware metrics. It will stay
>>>           with IEC conventions (i.e. to the base 1024) for software
>>>           metrics, according to what is customary according to
>>>           Wikipedia. We explicitly document which base applies for
>>>           each configuration option.
>> It would seem to me that use of upper and lower case suffixes is fairly
>> wide-spread (at least in my head) for choosing which base (1000 vs
>> 1024). Of course I can't remember which is which, but perhaps using this
>> approach would actually be better - and default values can just use
>> whichever letter-case they deem appropriate for the use-case.
> Hmm, I thought about something like that, but I thought we'd the ones
> inventing it, so I opted not to use that. Do you have some links which
> could show that this is a more commonly accepted rule?

Now you're testing me.... I'm convinced I've seen this before, but now
that the pressure is on, I cannot think of what projects used that
scheme... (all the obvious ones I looked at don't do that: dd,
dd_rescue, mke2fs etc. etc. parted sort of does it but uses multiple
letters so it's not the same).

> Note that in SI "m" is milli, and "M" is mega. Would be fun to store a
> couple of millibyte on disk!


> This new rule we adopted basically results in IEC everywhere with the
> exception of a few things like networkd's BitsPerSecond= setting. But
> there it should be really obvious that it is SI that is meant, after all
> "100Mbit Ethernet" or "Gigabit Ethernet" refer to SI prefixes. That
> means the SI vs. IEC should come pretty natural I think for all
> technical people the way it is right now. Or to turn this around, which
> administrator would expect that setting BitsPerSecond= to 954K is the
> right way to go for Gigabit Ethernet?

Actually, yeah, thinking about this more, I guess you don't really need
to learn the rule at all anyway... I mean doing the expected thing in
the expected place should be sufficient and I shouldn't worry about what
it means... I guess I may look it up the first time, but then thereafter
forget about it and not worry.

So after thinking about it a bit, I actually do think it's good how it's
done now :)




Colin Guthrie

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