Re: Minimum RAM size requirement of the MIPS port

[Simon Burge <simonb%NetBSD.org@localhost>]

Hi Hakurei,

Hakurei Reimu wrote:

> Hello everyone. I want to know the minimum RAM size requirement of
> running latest NetBSD on a MIPS machine.
>
> I want to port latest NetBSD to Microchip PIC32MZ, which is a powerful
> MIPS32r5 microcontroller with FPU, MMU, L1 Cache and 512KB of RAM.
> Since it's capable of running the original 4.4BSD (See
> https://hackaday.com/2016/01/04/litebsd-brings-4-4bsd-to-pic32/), and
> NetBSD is 4.4BSD's closest relative, I want to know if it's possible
> to run NetBSD on it.

The smallest MIPS kernel I have laying around is for MIPSSIM which
has only two or three device drivers and is far larger than your total
RAM size:

	   text    data     bss     dec     hex filename
	3771444  719632  103872 4594948  461d04 MIPSSIM/netbsd

If I trim out most optional things, this only gets down to:

	   text    data     bss     dec     hex filename
	1995244  101392   58864 2155500  20e3ec MIPSSIM-small/netbsd

which is still far too large.

I would think 16MB of RAM would be an absolute minimum to do much more
than boot with NetBSD.  32MB should be reasonably usable for a minimal
system.

Looks like the compiled kernel for LiteBSD is around 500kB.  Impressive!

Cheers,
Simon.