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Leo-N
December 2nd, 2009, 07:19 PM
Hi! I've got a problem when I update my Ubuntu 9.10 in my LiveUSB (not temporally) with all the updates. When I update, it goes ok but when I restart, the USB don't load the OS. I think that it will be one update, but I don't know what will be. Anyone knows what update is?

efflandt
December 2nd, 2009, 10:59 PM
If you have enough persistent data (ext3 file system in casper-rw file) you can add users, make certain settings, add packages, etc. That is rather insecure anyway, since it boots as the default user who can do anything they want to (if they know how). Some things from the iso image cannot be changed (or changes may not stick). So you should not really try to upgrade existing packages built into the iso.

If you want to do that, install an actual system on USB instead of the live iso. You would need a minimum 4 GB flash, but 8 GB or larger is recommended. Use tmpfs for /tmp in /etc/fstab (see fstab of live CD or USB for example).

Or more practical if you do not always need it in your pocket is a portable USB hard drive (shrink the vfat partition and make whatever swap and partitions for Linux). Just pay attention to Advanced button near end of install to put grub on USB mbr, instead of default main drive mbr.

Leo-N
December 3rd, 2009, 09:39 PM
I've got Ubuntu 9.10 in the USB, but the problem is that the version installed have updates (obvious, the version was released 2 months ago) but, if I install all of them, later the OS don't load. I will know what updates are problematic with this combination.

zebtonson
January 26th, 2010, 04:29 PM
I think the problems with updating a live usb install w/persistence for ubuntu 9.10 come about when updating the kernel. Usually when i want to update i just de-select anything that has *-kernel-* or starts with linux*.

I don't know the exact details, but i think it has something to do with the live usb doing something like a diff with the installed packages on top of the "livecd image", and trying to do something as low level as updating the kernel, confuses it during the startup process.

Herman
January 26th, 2010, 08:14 PM
The 'Persistance' type of USB Ubuntu installation is more like running Ubuntu as a Live CD and not quite the same as the real hard disc installed operating system.

Persistence installs are useful because we can use the LiveCD installer for installing Ubuntu in other computers.
It's also possible to get Ubuntu running in a very small USB disk since the live CD part of it only needs around 700 mb of disc space.
The Live CD has always had the ability to detect video hardware and set itself up automatically at boot-up in almost any computer.
In the days before Ubuntu Hardy Heron was released, flash memory was expensive, 2 and 4 GB sticks were about all that were available because that's about all most people were willing to pay for.
Flash memory quality was poor and flash memory had a bad reputation for wearing out, so even if we could fit a regular operating system in a flash memory stick, it wasn't regarded as a wise idea.


Since Ubuntu Hardy Heron came out back in 2008 featuring the Xorg 7.3 (http://www.ubuntu.com/getubuntu/releasenotes/804overview#head-34da8c8d2432823a293ea6a0639fe8b9a24c0f77) Xwindow system from X.Org Foundation (http://www.x.org/wiki/), regular Ubuntu installations also have the ability to set themselves up automatically for different video hardware at boot time.
It's a lot simpler to just install Ubuntu in a USB in the same way as we install Ubuntu to any other kind of drive.
The prices for USB flash memory drives have come down since Hardy Heron came out and the sizes most people are buying have increased.
Now 8 GB and 16 GB flash memory sticks are quite common and not too expensive, so a regular Ubuntu installation can easily fit in most flash memory sticks now.
Flash technology has improved and flash memory wear is not such a big problem anymore.
Some computers are being made with flash memory instead of hard disk drives and SSD drives are starting to become popular.
The maximum speed through the USB2 interface is not as fast as when the drive is plugged into the motherboard by an IDE or SATA cable, but it will still give you quite a usable system.
We now have the ext4 file system as our default file system for Ubuntu and the ext4 file system is particularly friendly to flash memory discs.
With a regular Ubuntu install in a USB device it's possible to get kernel updates and to follow how-tos in Ubuntu Web Forums and install software like everybody else.

A plain regular Ubuntu installation in a USB flash memory stick is better unless the persistence install is needed to install Ubuntu in a computer without a CD/DVD drive.