The new ROM is a 1MB file that includes a micro 2.6 kernel incorporated.
This kernel is patched to keep it small and has the bare minimum of required features and drivers.
The kernel source has been modified to include the Cobalt hardware drivers and to provide the new booting method.
How Cobalt RaQs boot
In previous versions of the Cobalt ROM, the boot had a 2 stage process that basically involved booting a first stage kernel (the ROM kernel), then booting another kernel on the first partition of the boot drive. The first kernel started, looked for the second kernel, then handed over the rest of the boot rocess to the new one.
Our new ROM works in a slightly different way. The boot kernel starts up and looks for the sbinit boot scripts.
The scripts run a executable called kexec. This loads a second stage kernel into memory, and an initial Linux image.
Our second stage kernel is a modified "Enterprise Kernel" the same as a CentOS kernel, but with the Cobalt drivers built in.
Why would we want to boot from USB?
The traditional installation method for Cobalt RaQ servers has proven to work very well.
The network install method is ideal for a datacentre where you may have a "re-install" server hat is always on. The majority of RaQ users now do not have facilities like this. Re-installing requires hunting for a compatible network card, then setting up a network, burning a CD and finally trying to install.
Booting from a USB key is much easier. Place the USB key in the back of the server and set the LCD to boot from sda1. This also introduces the possibilites for remote re-installatiion. A problem server could be rebooted to sda1.
We have tried to make the ROM update process as painless as possible. the update itself is a PKG file that s installed through the BlueQuartz software update interface.
Upon sucessful installation, the operating system will stay the same, but the kernel and ROM have been updated. This makes it very easy for users that simply want to "update" to Strongbolt2.