Hardware Requrements for Linux on 405GPr
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.
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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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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
Quoted 7 lines · 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?
Quoted 12 lines
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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Quoted 5 lines · Mark Hatle fray-at-mvista.com |PPC Linux Embedded|
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/
Quoted 5 lines · 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.
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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Dear Steve,
Quoted 6 lines · in message <[email protected]> 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).
Quoted 2 lines
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
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Software Engineering: Embedded and Realtime Systems, Embedded Linux
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