Technical items: How does OS installation work?
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The OS installation process proceeds in the following steps:
- If the PC has a PXE bootprom on booting it sends a DHCP request. If everything works well the booting PC gets a response containing the requested network configuration. Equipped with this information the bootprom tries to retrieve the information if the PC shall do a local boot or shall load the opsi boot image. In the second case the PC will load the boot image - an image of a small operating system - into its RAM and boot it (by treating a part of the RAM as boot disk).
If the PC does not have a PXE bootprom the opsi boot image can be supplied by the opsi client boot cd. - The boot image connects to the depotserver to retrieve required data and does everything on the PC to prepare an ordinary "unattended" setup process on the PC:
- executing the required formatting and partitioning of hard disks,
- patching the "unattended" configuration file so that it contains the specifically necessary data on network configurations, drivers, users, shares, and so on,
- copying all required files (e.g. the i386 folder) to the hard disk,
- preparing everything for the next boot,
- and triggering the reboot.
- Finally the prepared PC reboots, a bootstrap system starts, and the target system installation process starts (e.g. the Windows setup.exe is called).
