[Arm-netbook] ingenic jz4760 eoma-68 card

[Joe Michael]

On Fri, 2013-03-15 at 11:26 +0000, luke.leighton wrote:
> On Fri, Mar 15, 2013 at 10:08 AM, Joe Michael
> <joem at martindale-electric.co.uk> wrote:
> > On Thu, 2013-03-14 at 22:07 +0000, luke.leighton wrote:
> >> ok, bit of progress.  i've tracked down an app note for a USB-to-SATA
> >> converter from JMicron [*1], worked out that the maximum limit of the
> >> jz4760 is 512mbytes of RAM and found a suitable RAM chip that looks to
> >> be around 45RMB (2 are needed).  that's about $16 for a pair of RAM
> >> ICs (!)  mad.  absolutely mad.  considering that 4 hynix chips
> >> totalling 1gbyte of 800mhz DDR3 RAM is under $5.
> >
> > You should be able to use the 1GB DDR3 and either not use half the chip,
> > or set a GPIO port pin to toggle from one set of RAM addresses to the
> > next and have say two independent Linux distros running at the same
> > time! :-)
> 
>  euuw, euuw, that's either very very sick, or very very sensible, i'm
> not sure which.
> 
>  actually thinking about it, if you used 2 GPIOs you could split into
> 4, address 2 of them at any one time, and use 2 as a large swap cache.
> 
>  or something dreadful.

Or something wonderful - put 2 CPUs and let them haggle with each other
for RAM access. With some hardware handshaking between the CPUs.
(Rapid address switching will cause the device to slow down to
average speeds of about 10MHz instead of 800MHz.)
Then you got proper dual core. With a little bit of glue logic,
some parts of the RAM could also be set up as shared RAM to get you
fastest communication between CPUs. One CPU could do a web server
or a database server. ARM microservers are becoming a big thing these
days. More sales and money for the first person(s) to be doing it
properly within power budgets.

>  ... anyone remember the Z80?  able to address *gasp* 1Mbyte of RAM!