Hello,
On Tue, 24 Nov 2015 15:53:10 +0000 Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
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RAM is (or will soon be) the inhibiting factor around the adoption of single-board computers.
I haven't paid enough attention to 32-bit ARM recently to say whether similar limits apply there,
absolutely they are - because the peripherals are all memory-addressed, and the boot ROM also has to be addressed somehow.
Just as x86-32, ARMv7 has physical address extension http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0438i/CHDCGIB... , so it can address more than 4Gb of physical memory. That still leaves 4Gb of virtual memory per process, and thanks god - bloating memory size doesn't mean growing its speed, so the more memory, the slower it all works.
Generally, it's pretty depressing to read this memory FUD on mailing list of "sustainable computing" project. What mere people would need more memory for? Watching movies? Almost nobody puts more than 1Gb because *it's not really needed*. And for sh%tty software, no matter if you have 1, 2, or 8GB - it will devour it and sh%t it all around, making the system overall work slower and slower with more memory. (I'm currently sitting on 16Gb box with constant 100% cpu load - it's Firefox collecting garbage in its 6Gb javascript heap - forever and ever).
For comparison, my latest discovery is relation database engines which can execute queries in few *kilobytes* of RAM - https://github.com/graemedouglas/LittleD and Contiki Antelope http://dunkels.com/adam/tsiftes11database.pdf