[Arm-netbook] EOMA server standard

[luke.leighton]

On Fri, Oct 26, 2012 at 4:43 PM, Gordan Bobic <gordan at bobich.net> wrote:

>>   no - that was referring to the existing EOMA-68 standard, which is a
>> standard designed for mass-volume appliances, *not* servers.  EOMA-68
>> just happens to include USB3, 10/100/1000 Ethernet and SATA-III.
>
> So you are saying a EOMA68 "desktop" card can't be used in an EOMA68
> "server" chassis?

 that's incorrect.  ok - it's assuming that there *is* an standard
which re-uses PCMCIA for server modular purposes.

> That's a serious limitation. What can be done to make
> them compatible on the overlapping pins/features?

 i thought long and hard about this, 18+ months ago, and i couldn't
think of a good way that didn't place a significant burden on the
electronics (cards, server chassis or appliance chassis).   so i
decided to focus on appliances first, and leave servers until later,
maybe find a different connector or something.

>>   yes.  but in doing so, you now force *all* devices to have *exactly*
>> those features.  they can NOT be optional.  so if the standard
>> requires 2x 10/100/1000 Ethernet, then any SoCs which do not have 2x
>> 10/100/1000 Ethernet are automatically excluded.  likewise for any
>> other features.
>
> Why can the features not be optional? Why is it necessary for the card
> to support 2 ethernet ports just because the chassis can handle it? Why
> not simply leave those pins disconnected?

 i've been over this a number of times, but let's go over it again,
can you please double-check and see if i missed anything?

 ok, let's say that you have a chassis with 2 ethernet ports and 2
SATA drives.  one is the boot drive, the other the data drive, and
it's for a router system.

 card blows up: you rush out, buy another one, put it in and FUCK the
FUCKING thing doesn't boot, what the hell's wrong with this thing??

 turns out you bought a card that only has *one* SATA and *one*
ethernet: it won't boot, and not only that, but when you swap the
drives over in the chassis to find this out, fuck me if it doesn't
route the damn traffic because there's no 2nd ethernet on the card.

 i'm using swear-words because if i was in a data centre and i bought
a replacement card and it didn't work as advertised and my job was on
the line, i would *definitely* be swearing :)

 and i would be blaming that stupid, stupid "EOMA server" standard for
having done something as damn stupid as to make it possible for me to
get confused over not reading the words on the box at the store, "only
has 1 ethernet and 1 SATA".

 so rather than let that happen, the rule is: there *are* no optional
ports.  you can have "upgradeable functionality" e.g. offering 8 wires
for up to 1000 ethernet with the option either side to
down-level-negotiate to only 4, but definitely *not* "1 port is
entirely optional".

 this is something that was drummed in to me at university, from the
lesson our lecturer taught us about the X-25 standard.

l.