Tiny Core Linux/Reversion

A procedure for reverting an XO with OLPC OS to pristine filesystem configuration, as if it had just been installed, using Tiny Core Linux.

Identity, registration, Journal, post-install activities, and all customisations are lost.

Requirements

• an XO to act as a server,
• any number of XO to act as client to undergo reversion,
• a Tiny Core Linux bootable USB drive (tested on microcore-3.4-xo-2011-01-18.tar),
• a wireless or wired network.

Setup for Server

• install the required operating system build but do not boot into it, (or, having booted into it, follow the extra steps to fix side-effects of cloning),
• boot into Tiny Core Linux,
• remove the USB drive,
• configure wireless:

iwconfig eth0 essid NETWORK

• start the server:

xo-server

• note the displayed IP address.

Setup for Clients

• boot into Tiny Core Linux,
• remove the USB drive,
• configure wireless:

iwconfig eth0 essid NETWORK

• restore the filesystem to pristine state:

xo-revert ${IP}

(where ${IP} is the IP address or host name of the server)

• reboot:

reboot

Timings

Reversion of three XO-1.5 that had been booted once into 10.1.3 os860 cost 1m 45s each as compared to 17m using fs-update and over half an hour using NANDblaster.

Optimisation

Using /versions/pristine

Since a local pristine copy of the build exists, it can be used first to reduce the data required:

rsync --archive --delete \
/mnt/mmcblk0p2/versions/pristine/860 \
/mnt/mmcblk0p2/versions/run/

However, since /home/olpc is not present in this pristine copy, the full rsync is still required. In the test case, the local copy cost 16s, followed by the full rsync at cost of 1m, a saving of about 15s.

Using a non-XO server

(placing the rsync daemon on a server system)