I've just set up booting from an MMC card on my N800 and just wondered what other people are finding the biggest benefits are, and how they are using it.

Is it for faster booting and faster operation? I can't say I notice much difference either way.

Or is it to bulletproof the device, so if it fails to boot from flash you can boot it off the card? Or the other way round so if it fails to boot from the card you can boot from flash.

Is there a need to keep the two in sync, so if you install loads of apps in the card and boot off the card, they will still be available if you boot from flash?

Or do you keep a card with the OS cloned on to it tucked away in a drawer as an emergency boot disk?

I'd be really interested in hearing how people are making the most of booting from MMC - any other useful tips or hints or tricks that provide useful benefits that you can only do if you have the option to boot from a card much appreciated!

I'm also interested in how it would benefit user to boot from mmc. I haven't found direct answer yet and I think somebody have to "sell" the idea and all benefits it brings to me. I'm willing to "buy" the idea if someone will "sell" it to me. So how about, people are ready to try new things if they just want to do that.

well, just a few things that come to mind immediately...

- much more space for installed apps
- much more space for app data files, with no effort to set links or whatever to get them to store data on the external mmc card
- fallback to standard flash install if/when you do something to mess up the mmc install, and then hopefully be able to fix the mmc install (you'll need modules to mount ext2fs or whatever you use for filesystem on the mmc)
- remove the external mem card, boot to flash, and back up the complete mmc filesystem over usb (again you need to be able to mount ext2fs or whatever from pc, not a problem if you run linux), or backup using an external card reader
- variation on above, be able to get your app data off the mmc card if/when you screw up the install and it no longer boots and you didn't bother to backup
- (bootmenu, not mmc boot advantage) can now access the standard flash install filesystem over usb networking through new bootmenu, giving many of the same backup/recover advantages to the flash install as for mmc install above - and installing bootmenu is a prerequisite to booting off mmc

'much more space' above defined as your mmc card size minus whatever the standard flash mem is - 64mb on n770, 256mb on n800? I have an 8g sdhc card in the internal slot as my normal boot option, with the internal flash as the only alternative.

and yes it is a little bit faster booting, but as far as I can tell the normal IT use case is not supposed to involve regular rebooting.

rob.

As for the speed, it is significantly faster than internal flash only with N770 and kernel with faster MMC speed http://fanoush.wz.cz/maemo/#mmcplus if you have card that support such speed and works reliably (my Kingston 2gb mmcmobile). Also it is faster with N800 and kernel from Philip http://intr.overt.org/blog/

With unmodified kernel the speed advantage is not significant. Pure read/write speed may be even similar, same or slower but what also counts is CPU usage. Internal flash is compressed so every access needs CPU power to compress/decompress data. In some situations this performance hit can be visible (more with N770). With system on MMC the CPU is free to do other tasks while reading/writing.

Thread revival since I've only just done this myself and installing the faster kernel.

Everything robmiller said, especially the extra space for apps/data/et. al.


As for speed advantages - I can't notice any difference booting. But some difference during usage, refreshing large forum web pages/gmail/etc (you'll see it in the Load Monitor applet - CPU usage is down considerably!) You'll also see it where you have a large number of repos and refresh the application manager.

Everything feels a little more responsive.

when booting from mmc/sd can you turn the internal flash into swap space? I don't see myself using the internal for anything if I am booting off a >2GB SD card... so wouldn't it be to my advantage to turn the internal flash into swap, thereby increasing my "ram"

also, (might as well ask this too) if booting off a >2GB SD card, can I actually partition the space so I can use part of the SD card as swap? Just trying to get a feel for my options on this one...

Will this benefit Diablo users as well or is Diablo's card access already optimized?