4. How Does It Work?
- Bootloader - The bootloader, ARLO, does for EPOC what Loadlin does for
Dos. It releases the memory from EPOC, places the kernel and initrd in the
appropriate places in memory, and then boots the Linux kernel. The initrd
is not necessary if you have a linux system installed on compactflash. All
EPOC information is lost from memory as linux takes over. Thus, if you don't have
a compactflash disk, then you have to reinstall linux (ARLO, kernel, initrd) to
EPOC the next time you reboot - and you will have lost any information
you created in EPOC or linux if you did not backup.
- Kernel - The kernel has patches applied to it, which makes it compile for
ARM based systems, and also has a few more patches for the Psion hardware.
The kernel port to the Series 5MX is quite functional now, with development
continuing (power control, screen support, ethernet, sound, etc. are
- Initrd - This is a virtual file system image, which contains a miniature
installation of Linux. These can range in size, but the more RAM used for the
ramdisk will leave less memory available for the operating system. The kernel
loads the initrd image as the root partition. For fully functional installations,
installing a system on compactflash disk is preferred.
- Compactflash Disk - The linux installation can be set up on a compactflash
disk, which behave exactly as IDE disks. The kernel will boot up, find the
root partition on the disk and proceed as in any other linux system. The use
of compactflash disk also means that all information is saved on disk, so that
the system (including ARLO and kernel) is stored to disk for any reboots.
- Because the EPOC system is stored in ROM, it is always available. Dual
boot systems, so you can go between EPOC or linux as you like, work very well.