• Registered: 2009-07-16
  • Posts: 8

Topic: Flash and persistence

well,
first of all I would like to thank the developer and mantainers of this wonderful marvel; this forum/comunity is amazing as wel.
I am just a linux enthusiast, I have all my machines working on linux.
Since I am quite new I found mini distros to be very useful when it comes to learning.
I have been surfing the net looking for mini distros, I must say that ttylinux is a winner.
I have succesfully installed it on a HD partition of my old (but trusty) Toshiba PI 133 notebook.
It works perfecly.

The reason for my post, besides congratulating everyone involved with this project, is a new challenge (for my modest linux knowledge). I used ttylinux-flash to install ttylinux on a spare 64mb SD card following the provided document. As a result, my eee PC boots smoothly from that card. According to my level of ignorance I have many doubts (a minimal distro like ttylinux facilitates the learning process, as I mentoned before). My main concern now is how possible is to store documents and modified settings in that SD (what I came to understand that is called persistency).

I have read every post on this subject in this forum and even though I do not understand many  of the issues covered I think I understood that it will not be an easy task for me. (the conversation between karol and maurice has been very helpful)

Any suggestions?

Thanks!
chop wood, carry water
ps.: sorry for my english (I am learning that as well)

  • From: the ether
  • Registered: 2008-11-14
  • Posts: 350

Re: Flash and persistence

We need Maurice, and he will reply soon.

Maurice: I'm not familiar with using flash disks other than USB  flash drives. If vincenzo used my ttylinux-flash script to install, then there must be a standard block device, like /dev/sda, that he installed into; so his SD card must be recognized that way. This is the problem that there is no way to know what that device is once ttylinux is booted. I need to figure how to support UUID for block devices and use that in some ttylinux-resident script to reliably mount the correct flash device, preferably upon boot. Right now, for vincenzo, it is just a matter of knowing what /dev/sdX to mount and save his data there, no?

douglas's Website

  • Registered: 2006-06-12
  • Posts: 469

Re: Flash and persistence

Hey vincenzo (and douglas)!

The 'problem' with the sd interface on an eeepc is that it is connected to usb.  On the plus side that means it can be handled the same way as regular usb flash disks so any input Douglas has about it should be directly applicable.  On the minus side, if Asus would have wired it into the same controller as the onboard flash thingy (mini-pcie on newer ones, mini-pci on the first ones they released) then a sd card could have been handled exactly the same as a regular drive.  The reason I know that it won't work the same as a regular drive is that I tried it despite guessing correctly that it wouldn't work.  Had to be tried though.

Will it work?  For sure but it'll have to be done the way I've been posting about usb flash disks all along.  If that is suitable to your requirements for the sd interface on your eeepc then I am more than willing to attempt it here and perhaps between us we can come up with a rootfs that will meet your needs for such a thing.  The current ttylinux kernel isn't quite compatible with the eeepc but it can work.  I'd advise we try a more recent kernel though and have had excellent results with kv-2.26.30.1 and usb flash boot/root which should be perfect for the sd interface on eeepc's and the like.  Should even work on usb card readers on regular pc's.

Life is good,
Maurice

  • From: the ether
  • Registered: 2008-11-14
  • Posts: 350

Re: Flash and persistence

The latest ttylinux release makes use of updated e2fsprogs capability. If you use the ttylinux-flash script in the latest ttylinux to put ttylinux onto a flash disk, then ttylinux will automatically look for the flash disk it booted from and run a user-maintained script if it finds it on the flash disk. This script is on the flash disk and is expected to be maintained by you. It has the option of leaving the flash disk mounted or not, and the device node, such as "/dev/sdb1", is an argument to the script so you can store or display it. The flash disk will be mounted at /mnt/flash.

douglas's Website