Subject: Re: MTD devices in NetBSD
To: Garrett D'Amore <>
From: Jachym Holecek <>
List: tech-kern
Date: 03/23/2006 23:52:18
> >> On NAND, you can't have a bootloader like that.  As a minimum, the
> >> bootloader needs to be able to deal with bad block management.
> >
> > Not true.  (See my earlier reply about this.)
> But if you've hidden away the mapping with some kind of block remapper,
> you don't have a good way to write those blocks.

[Assuming you choose to go the "wear levelling layer" way, which I have
 no qualified opinion on.]

Is there a good reason why the block remapper should be prevented from
only operating over a couple of flash device extents and leaving the
rest mapped 1:1 (in other words, have the bootloader partition 1:1 and
only block-remap the "/" partition)?

You'll have the very same issue for NOR devices, AFAICS.

> The systems that use NAND are likely to have the NAND part
> locked away behind a USB or CompactFlash adapter.

They definitely are NOT, but that doesn't invalidate your point of
focusing on NOR right now and leaving NAND for later/someone else ;-)

	-- Jachym