Subject: Re: NAND flash support
To: Toru Nishimura <>
From: Jukka Marin <>
List: tech-embed
Date: 03/13/2007 08:40:45
On Tue, Mar 13, 2007 at 10:07:53AM +0900, Toru Nishimura wrote:
> I think it's one of mistakes Linux MTD has ever made.  NOR and NAND
> are distinct mammals not to able to feed the same meal.  In addition to
> structural differences of their substance, operational difference poses
> issues on computer HW design.  NOR erase is slow.  So slow to complete.
> It will takes _tens_ of ticks for 100Hz timeslice.  One tech doc prepared
> by Toshiba in 2003 emphasises NOR takes 700msec for block erase.

Not to mention ST's M29W640: Block erase time 6 seconds (max), chip erase
time 400 seconds (maximum).  Yes, _seconds_.

> My opinion about NOR is that it will loose the popularity as general purpose
> storage soon (if not ever).  NOR will scale back to the age when it was used
> for small capacity "program store."

That's what we use it for.