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Revision as of 06:43, 22 February 2011 by Jankratochvil (talk | contribs) (+livecd-iso-to-disk fix)

Biarch Spin


Provide both 64bit (preferred) and 32bit distribution for PCs on a single flash disk >=2GB.


Detailed Description

Automatically prefer x86_64 (AKA amd64, Intel 64, EM64T) live boot and installation but still provide i686 (AKA Intel 32) live boot and installation for 32bit only PCs and/or recovery of 32bit installations.

Most installations can benefit from x86_64 increased performance thanks to twice the more available registers together with better new ABI resulting in less memory swapping, also thanks to 64bit calculations without registers pairing, more efficient addressing modes used for example in shared libraies and wider data management capabilities thanks to the unlimited addressing space. Still many installations are present in 32bit mode as people are not sure whether they have 64bit capable hardware. This installation can autodetect the best installation mode for their system.

Software developers can benefit from easier code thanks to the new addressing modes. Users can also benefit from the simplicity of a single kernel variant (no longer need for PAE and/or regular kernel variants).

Benefit to Fedora

Fedora can automatically provide the best suitable variant of the distribution for each user. User experience gets greatly improved.

Builder + Kickstart File

  * requires livecd-iso-to-disk fix in Bug 679023

ISO Name / FS Label

The shell script creates files in this order:

* f15-live-x86_64.iso
* f15-live-i686.iso
* f15-live.bin

If both .iso files already exist the f15-live.ks file is not used at all. f15-live.bin is a 2GB image suitable for flash disk (like /dev/sdX where X is for example d, CHECK THE MEDIA NAME IN YOUR CASE). You should never use the partition names (like /dev/sdX1). Example command is:

cat f15-live.bin >/dev/sdX

As the biarch image is provided as a flash disk image including partition table for one 2GB FAT partition the ISO label is not applicable. FAT image has label LIVE, both ext3fs.img files have label _f14-live. The images get found by UUID such as: root=live:UUID=7404-2829


No special dependencies are known.

Scope / Testing

The provided .ks file is not essential for this Spin, the .ks' file can be dropped. Just the default CD size times 2 is not much useful as the nearest higher available flash disks are 2GB. Therefore I have provided some additional packages in the supplied .ks file. I changed there some personal boot defaults but those can be either also dropped or imported to the system .ks files.

One should test it both with x86_64 hardware CPU (equivalent to qemu-kvm -cpu qemu64) and also with i686 hardware CPU (qemu-kvm -cpu qemu32) to verify ifcpu64.c32 boots the right distro variant. Real iron can be also used.

Spins Page



Automatic 64bit/32bit installation and recovery.

Spin description

Provide both 64bit (preferred) and 32bit distribution for PCs on a single flash disk >=2GB.



Download tab

Support tab

Users can contact although there is no specific code besides ifcpu64.c32 from the project syslinux.

Custom branding

None used.

Comments and Discussion