[Arm-netbook] 9nov11: progress on allwinner A10
Luke Kenneth Casson Leighton
luke.leighton at gmail.com
Wed Nov 9 20:44:03 GMT 2011
ok, just a quick thoughts / status update.
we've had it confirmed that the CPU is external 2gb addressing but
*internal* limited to 1gb (!)
little factory is still going over the BOM, but want to put in 512mb
DDR RAM ICs because they're cheaper.
they were planning to make room for up to 4gb NAND flash *but*...
something just occurred to me / my associates: thailand's under water.
the implications of that are that the factories which used to make
low-end IDE drives and pretty much every SATA drive under 80gb no
longer exist... and probably won't ever be rebuilt. everyone's moving
to SSDs for low-end, and the prices for larger HDDs are rapidly
now, for free software developers we don't give a rat's arse: there's
always room to cut down to emdebian, or use cramfs, or... whatever:
there's always creative ways to make a bit more room, but i've been
connecting the dots a bit from various peoples' input, talked it over
with my associates and we came up with an idea.
alain (williams) asked a very pertinent question, he said, "ok yep
count me in, but how do i make any money from this?" and it put me on
the spot and i went, "um, well... how about you do servers but use
these as low-power ones" and then i realised of course, he's a CentOS
maintainer, hosts some packages, so he's going to try CentOS for ARM
and then well if that works, he'll be the maintainer of the ARM port
of CentOS servers.
then we put two and two together and went, "hang on, these are
effectively blades, why not have a chassis like the ZT-Systems one,
with a gigabit backbone, space for SATA drives, and up to 8
EOMA-PCMCIA-compliant CPU cards, each with 1gb DDR3 RAM and these
Cortex A8s?" it'll all be low-cost, you can get 40gb to 80gb SATA
drives, turn it into a big software RAID or NAS box or a
high-performance (but higher-than-average latency of course)
load-balanced server aka cloud jobbie.
at which point i went "oh shit - low-end SATA drives don't bloody
*exist* any more!" :) [look on ebuyer's site for SATA drives below
£50 - there aren't any].
so _then_ i thought, hang on, NAND flash ICs in SSDs are like,
dropping like a stone as they pick up the slack from the fact that
low-end SATA and IDE drives don't exist, hmm, and the spec on the
allwinner CPU says that it has 8 NAND chip-select lines... why not ask
the little factory in shenzen if they can make room (on the other side
of the PCMCIA card) for another 7 4gb NAND flash ICs?
so if you wanted a "cheap" low-cost version, it'd be 512mb RAM with
maybe a single 1gb NAND flash IC; the next version up would be 1gb RAM
with a single 4gb NAND flash IC (again, single-sided so it's a cheaper
build cost); the insane version would be effectively its own SSD with
up to 32gb NAND flash, potentially 8x the speed of the 4gb version,
and people could do their own wear-levelling (i hope!), i remember how
everyone keeps bitching about how these bloody SSDs always get in the
way with the stupid, stupid assumption that there's going to be a FAT
or NTFS partition on it.
then, if you shoved 8 of those into a single rack you wouldn't _need_
SSDs or SATA drives unless you wanted a multi-terabyte server with 8gb
of RAM and 12ghz of raw Cortex A8 CPU horsepower (oh, and if f*****
ARM pulled their bloody finger out over the intransigent position
regarding MALI 400MP open source licensing, you'd get god knows how
much raw GPU power as well, all in well under what... 25 to 35 watts?)
i think i've got a 35 watt laptop PSU somewhere that might run that
lot, somewhere... oh yes, it's my (broken) dell laptop with its "Ultra
Low Voltage" 1.2ghz Dual-Core CPU, mmm....
ok. bit longer than i anticipated, but i do love a good story. sorry.
bottom line: anyone grok the above, would want to sell these
"promised" ARM-based servers we keep hearing about, but like, y'know,
actual real ones, please do speak up, and i'll see how to arrange it.
bear in mind that, thanks to the EOMA-PCMCIA specification, it will be
possible to swap out the CPU cards with anything else that comes along
in the future which also has 10/100 ethernet and SATA-II (possibly a
Cortex A9 which would then have virtualisation - A8s *don't* have
virtualisation), but no, you can't have 10/100/1000 or SATA-III this
really _is_ at the "low-cost" and "low-power" end, going a bit on the
odd side perhaps, pushing that "low-power equals a bit higher latency"
thing a bit further along than is usually expected, but i believe the
concept has merit.
but... what's more important than what _i_ think has merit is what
_you_ think has merit :)
p.s. if you're thinking that thailand's going to get its factories
back any time soon, you have to bear in mind that it's not the typhoid
or the trenchfoot that's going to kill the most people, it'll be the
deadly poisonous snakes that were flushed out and will now be living
where all the humans want to be, once the water subsides. whoops...
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