[Arm-netbook] laptop main board, power board and ingenic jz4775 cpu card

[Paul Boddie]

On Tuesday 24. November 2015 14.42.44 Luke Kenneth Casson Leighton wrote:
> On Tue, Nov 24, 2015 at 9:06 AM, Paul Boddie <paul at boddie.org.uk> wrote:
> > This is great news! I also like the 2GB RAM support - with many ARM
> > single- board computers still only supporting 1GB, it makes sense to go
> > for the maximum here -
> 
>  those kinds of decisions i believe are usually made based on the
> faulty logical analysis which is summarised as "but... but.... the
> processor costs less than the memory!!!"

RAM is (or will soon be) the inhibiting factor around the adoption of single-
board computers. People forgave the first model of the Raspberry Pi for having 
256MB RAM because it was only supposed to be used for "lightweight" tasks, but 
people's expectations tend to increase when they realise that these devices 
could replace their primary computer.

I suppose that you could cluster several of them if they each only provided, 
say, 1GB RAM, but then you need the convenient infrastructure to make that 
easy. Indeed, a multi-slot cluster unit would be nice with EOMA-68, and I 
think someone mentioned something similar earlier in the year. The software 
architecture would also need reconsidering, however.

As I understand it, 32-bit MIPS divides the addressable memory space in two, 
meaning that 2GB of actual memory is the limit. I haven't paid enough 
attention to 32-bit ARM recently to say whether similar limits apply there, 
but a move to 64-bit architectures is necessary to address over 4GB, anyway, 
and that would be the motivation for doing it. (Which is why I was baffled by 
the Olimex "64-bit" device that was only going to provide 2GB RAM.)

> > and the USB boot mode support, which is great for experimenting
> > with new boot payloads and is one of the nice things about the Ben
> > NanoNote.
> 
>  same company.  nanonote is the jz4720.

Yes. The NanoNote deliberately exposed the USB Boot pins to facilitate 
experimentation, whereas the Letux/Trendtac Minibook/MiniPC (which uses the 
mystery jz4730) apparently requires more work to mess around at the booting 
stage. I also noticed that the MIPS Creator CI20 has USB Boot (using a jz4780) 
as well. And the (micro)SD Boot mode is also very handy, of course.

Paul