Hardware Requrements for Linux on 405GPr

Hardware Requrements for Linux on 405GPr

[Stephen Williams]

We are in the process of designing a PCI board that will have
a 405GPr, some SDRAM and a Compact Flash. (Not to mention
the functionality of our device.) Outside the 405GPr itself,
are there any minimum device requirements for a Linux that
can for example run some simple servers?

For example, the matter of whether or not a RTC is required
came up amongst the designers.
--
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."


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Re: Hardware Requrements for Linux on 405GPr

[Mark Hatle]

An RTC is not required for Linux.  Many designs I have seen do not have
one.  However, an RTC is an excellent device to have available!  Various
applications and services may require a consistant, ever increasing
time.  NFS is the one that comes to mind immediatly.  If the device is
rebooted and the time goes back to default, NFS may have problems.

RAM is something else thats nice to have.. :)  While 16 MB is usable, 32
MB or more is preferred in the applications that I am used to.  (You can
get away with 8 MB, but thats very tight usually.)

--Mark

Stephen Williams wrote:
>
> We are in the process of designing a PCI board that will have
> a 405GPr, some SDRAM and a Compact Flash. (Not to mention
> the functionality of our device.) Outside the 405GPr itself,
> are there any minimum device requirements for a Linux that
> can for example run some simple servers?
>
> For example, the matter of whether or not a RTC is required
> came up amongst the designers.
> --
> Steve Williams                "The woods are lovely, dark and deep.
> steve at icarus.com           But I have promises to keep,
> http://www.icarus.com         and lines to code before I sleep,
> http://www.picturel.com       And lines to code before I sleep."
>
>
>
>
>


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Re: Hardware Requrements for Linux on 405GPr

[Stephen Williams]

Mark Hatle fray-at-mvista.com |PPC Linux Embedded| wrote:
> An RTC is not required for Linux.  Many designs I have seen do not have
> one.  However, an RTC is an excellent device to have available!  Various
> applications and services may require a consistant, ever increasing
> time.  NFS is the one that comes to mind immediatly.  If the device is
> rebooted and the time goes back to default, NFS may have problems.

The first iteration of this device will HAVE a PCI connector and
go into a PCI slot of a host computer, but it will have a network
interface as well, to provide some minimal services such as a web
server for configuration and so forth. I can't thinkof anything
right off that will need the correct time, but who knows.

Well, actually there is logging.

As for memory, 64M of SDRAM w/ option for 128meg, and flash enough
to write a bootstrap loader to get the O/S off CompactFlash card.

--
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: Hardware Requrements for Linux on 405GPr

[Michael J. Accetta]

Mark Hatle wrote:

> An RTC is not required for Linux. Many designs I have seen do not have
> one. However, an RTC is an excellent device to have available! Various
> applications and services may require a consistant, ever increasing
> time. NFS is the one that comes to mind immediatly. If the device is
> rebooted and the time goes back to default, NFS may have problems.

You can defintely run into problems with NFS and no RTC. We have a setup
like this and without a RTC, NFS would end up allocating (I think)
request id's based on the time that might be cached on the server to
handle replay. With the time always starting at 0, different requests
with the same id could be issued from the card across boot sessions and
the server would have cached the old request, producing some confusing
results when it replied to the cached rather than new request. Our
solution was to add a TIME protocol probe in the ipv4 BOOTP path so the
card always got the right time before continuing the boot.

Mike Accetta


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Re: Hardware Requrements for Linux on 405GPr

[Wolfgang Denk]

Dear Steve,

in message <21518-79162@sneakemail.com> you wrote:
>
> We are in the process of designing a PCI board that will have
> a 405GPr, some SDRAM and a Compact Flash. (Not to mention
> the functionality of our device.) Outside the 405GPr itself,
> are there any minimum device requirements for a Linux that
> can for example run some simple servers?

You need some boot device (flash?); you  need  some  RAM  (>=  16  MB
recommended).

> For example, the matter of whether or not a RTC is required
> came up amongst the designers.

If you don't need a current time of day then no RTC is needed.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Ever try. Ever fail. No matter. Try again. Fail again.  Fail  better.
                                                        -- S. Beckett

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