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pterjan's diary


2009-04-10

  Mandriva Live USB

I was reading various tutorials on how to use LiveCD on USB stick with Fedora or Ubuntu.

They all use complicated methods even if sometimes scripts or graphical interface are provided to hide.

There is however a very fast and simple way to make a .iso bootable on USB, isohybrid script provided in recent syslinux. It works quite fine except that some BIOS and some partitioning tools don't like that the first partition says it starts at 0. We have a very simple patch on Mandriva to make it work on such machines. We used it on Mandriva 2009 Spring RC1 GNOME Live iso and got no negative report, so it is now used on all Live CD since RC2.

Actually we got several negative reports, but it was always because people copied the iso into the first partition and not at the beginning of the key (i.e. onto /dev/sdb1 instead of /dev/sdb) despite it was stated quite clearly on the wiki: where /dev/sdX is the path for the device of your USB stick and X is a only one letter (not one letter and one number). For instance /dev/sdc or /dev/sdd are correct, /dev/sdc1 or /dev/sdd2 are not correct and won't work..

Because of that, we now have a graphical interface (based on Fedora LiveUSBCreator for the UI) which allows you to select the iso image, the usb device and perform the copy. Windows version will arrive soon.

Today's TSUKKOMI(Total: 17) [Add a TSUKKOMI]
  H. Peter Anvin (2009-04-10 21:05)

This is an interesting thought. It might be possible to make the ISO-as-partition work with isohybrid without too much work.

  Benny (2009-04-10 21:46)

Isn't that what you want: https://launchpad.net/usb-creator <br>Just used it yesterday, worked like a charm.

  Erwan (2009-04-10 22:24)

The proper url is : <br>ftp://ftp.free.fr/pub/Distributions_Linux/MandrivaLinux/devel/tools/mandriva_seed.sh

  foo (2009-04-11 04:02)

Please send that patch upstream!

  jef spaleta (2009-04-11 04:45)

question, is the usb image creation you are talking about here non-destructive, in that can you do the install while leaving the existing data files in tact on the usb drive? Or are you effectively wiping the usb stick and dedicating it as a bootable linux image?<br><br>Does your method also provide data persistence across usb boots? Or is it more like a livecd in operation returning to the same original state on each boot?<br><br>-jef

  glyj (2009-04-11 09:25)

1. the partition table on the key is overwritten, so : almost everythink is lost (unless you restore the partition table and use some tools to restore the filesystem...and may save some files)<br><br>2. the system on the usb key behaves exactly as a ONE live CD (it's readonly). If you want persistence across usb boots, you'll have to work a little (or to by a mandriva flash ;-) )<br><br>regards,<br>glyj<br><br>PS: pterjan, correct me if I'm wrong ;-)

  Pascal (2009-04-11 09:54)

foo: I had sent the link on IRC but upstream does not really like it<br><br>jedf: It destroys the content of the key, and just transforms the normal livecd into a liveusb without changing anything to its behaviour.<br>You can add partition on the free space and it will be mounted, but you have to put yourself useful info there. We have Mandriva flash which provides persistance (using unionfs) but what I'm talking about here is just transforming very simply any LiveCD into LiveUSB.<br><br>glyj: yes

  Adam Williamson (2009-04-11 18:36)

pascal: the things Jef talks about are what Fedora's tool does. It's a very simple tool (you run it with just a couple of arguments - the ISO and the destination). Competition is great but please don't go over the top, the Fedora tool is not needlessly complicated.<br><br>There's a graphical interface for Windows because no Windows user ever wants to run anything at a DOS prompt.

  jef spaleta (2009-04-11 20:47)

<br>Pascal, <br><br>ah yes that's right Mandriva flash..which is a separate image target, so it make more sense now why you didn't see the additional features available in Fedora's tool as valuable. <br><br>Fedora's approach to "flash" targets is different than Mandriva, the livecd iso is the basis of a persistent usb (or sd card) target and the Fedora tool allows one to create such installs on demand locally...without destroying existing data on the device..assuming you have the room for it. What's more since Fedora has a number of livecd image spins maintained by the community, the tool works equally well to turn those spins into persistent usb images too. It makes for efficient use of resources. Instead of making livecd and "flash" targets available as primary image targets..livecd images are converted to "flash" targets on demand. Because of that we can have Fedora Electronics Lab as a persistent usb image on demand and individuals can take their work and their open design tools to another computer. without having to hold a separate "flash" image for download.<br><br>The Fedora ambassadors have even come up with a clever filling station graphic for events to make use of the feature to hand out data persistent usb images.<br><br>-jef

  Pascal (2009-04-11 23:49)

Well I think we don't understand each other.<br>isohybrid (that we did not write) converts in a few seconds a live cd iso into an image which is suitable both to be burnt onto a CD or a USB key. <br>It just adds the appropriate info at the beginning of the iso, without caring of the content. That's why I say it's fast and simple compared to other tools.<br>We run it on all livecd that we produce, this way all what people need to put the iso onto the key is dd.<br>That's why I don't see the tools valuable, all what we need is a graphical dd for people who don't know how to use dd right. We need no intelligence.

  neo (2009-04-12 17:13)

The Fedora method which preserves data on the USB disk and allows you to store information persistently on the USB definitely has its advantages. isohybrid can easily be used in Fedora as well. No big deal.

  Pascal (2009-04-12 21:56)

"No big deal" but have you seen any tutorial speaking about it ?<br>That was the point of this post

  jef spaleta (2009-04-12 23:37)

Pascal,<br>the question becomes...how valuable is a liveusb without data persistence? Perhaps the real value in the flash media format is the fact that its rewritable. Perhaps building strict duplicates of "live" images designed for cd-r media that don't inherently taking advantage of the rewritability of the flash memory aren't a compelling use of the flash medium compared to image creation processes which give you data-persistence and non-destructive installation features. <br><br>There's a reason why Mandriva Flash exists as a target...and its probably the exact same reason that Fedora's community hasn't so far thought to write a howto for the rather simple hybridiso change. Strictly "live" usb images are just not that interesting a use case compared to the value of producing data-persistent usb images. <br><br>Just because its easy to do, doesn't make it worth doing. Yes data-persistence and non-destructive installation are more complicated things to do..but the end result is far more valuable by making better use of the capabilities of the flash media. <br><br>I think both Mandriva and Fedora realize teh value in data persistence, its just a difference of approach. Fedora's found a way to build things in such a way that the value of data persistence can be shared with the community so the community can extend that value by making all sorts of data persistent Fedora remix images. Mandriva's approach has been to take the value of data-persistent and turn it into a product offering.<br><br>-jef

  Pascal (2009-04-12 23:42)

Well I agree this is useful, but the usage is not the same.<br>A lot of people have been asking for a way to run the livecd and install from it on their netbook without cdrom drive.

  Charles (2009-04-13 15:57)

Is it possible to use it on the Free images also? I would love to get rid of all this dvd burning... DVD's cost lots of money.

  Adam Williamson (2009-04-13 19:29)

"the question becomes...how valuable is a liveusb without data persistence? Perhaps the real value in the flash media format is the fact that its rewritable."<br><br>Well, for a lot of situations the value is just that the system you're trying to install on has a bootable USB port but no optical drive. E.g. every netbook ever.<br><br>For Mandriva it was a bit ironic that, up till 2009.1, Mandriva was probably the distro with the best support for netbook hardware...but didn't distribute any installation image you could easily boot on a netbook. This fixes that problem. It's a good thing, I just wish the post hadn't taken such a needlessly oppositional tone.

  Pascal (2009-04-13 23:16)

Well sorry if you felt it like that. I started with that because I saw that day on LXER the Ubuntu tutorial and felt sorry that still nobody knows about isohybrid which is great for this simple use case.<br>I did not mean to say anything negative about the available tools, just that there is this very simple (and fast, it needs a few seconds to make the .iso bootable on usb) tool which is nice when you just want to use your livecd as liveusb and that surprisingly nobody ever mentions it.<br>Maybe I should not have linked to Fedora :)


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