This is the mail archive of the ecos-discuss@sources.redhat.com mailing list for the eCos project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: why scrub memory?


This seems reasonable enough... however, isnt all memory that is going to be 
used written to before it is used?  Does Ecos/Redboot assume that the memory 
has been written with zeros when it uses memory?

thanks,
Aaron


On Friday 20 June 2003 02:38 pm, Mark Salter wrote:
> >>>>> Aaron Richardson writes:
> >
> > I see on several platforms (including the one that I am working on) that
> > memory scrubbing is occuring.  Why is this done and can I remove it?  I
> > am tired of waiting the time for this occur.  I have 256 MB of memory
> > right now, but plan on having much more in the future.
>
> When the ECC memory is first powered on, it must be written to
> before it is read. This syncs the ECC code bits with the data
> bits. The simplest approach is taken and all of memory is
> scrubbed before any is used. If the application that RedBoot
> boots (or the standalone eCos app) is not going to muck with
> the MMU, then the HAL could be enhanced to defer scrubbing a
> given memory page until that page is first touched. But only
> if that's not a performance problem for the app.
>
> --Mark

-- 


Aaron Richardson
aarichar@cisco.com
512-378-1286


-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]