Build system

Description

The OLPC XO software build system has the requirement of combining software from various sources:

• A specific set of packages from Fedora Linux
• Some OLPC-specific packages which are not available in Fedora
• Some OLPC-forked packages where the versions in Fedora do not suit our needs exactly
• Sugar activities
• OLPC-specific configuration

The build system outputs software images which can be flashed to XOs for testing and deployment.

While OLPC produces generic software images, almost all deployments will want to add some level of customization (specific Sugar activities and software applications, default settings, etc). To allow for this, the build system can be easily installed and used by deployments and developers, allowing for easy local customisation.

Current build system

OS Builder is used for current and upcoming OLPC software releases. Compared to its predecessors, it makes extensive use of Fedora's build tools under a higher layer which allows for organisation of components and easy customization. It is also easier to install and use.

Files produced by the build system

The build system produces sets of files for each targeted OLPC model, some starting with the build's number such as os883. The filename extensions include:

activities.txt, libraries.txt

the default Activities and Collections incorporated into the build.

.files.txt.gz

a directory listing of the filesystem image, compressed. You can enter a command like `gunzip xxx.files.txt.gz` in a terminal to uncompress this to xxx.files.txt.

.img

JFFS2 file system image for the XO-1. The XO-1's firmware knows how to copy this to its NAND flash memory.

xxx.yy.md5

cryptographic hash of the contents of the file xxx.y. You can enter a command like `md5sum xxx.yyy'` in a terminal to verify that the file you downloaded is identical to the one created by the build.

.onu

UBIFS file system images for the XO-1?

packages.txt

the existing GNU/Linux packages assembled by the build system to produce the build. Many come from Fedora unchanged.

.toc

Information for performing a system update using olpc-update without requiring network access, see also .usb

.tree.tar.lzma

The contents of the filesystem image. If you carefully unpack this onto a Linux partition on a USB drive or SD card and make some changes, you may be able to boot an XO from it.

.uim

UBIFS file system images for the XO-1 ?

.usb

Information for performing a system update using olpc-update without requiring network access, see also .toc

.zd2 , .zd4, .zd8

special compressed images (??) of the XO-1.5's file system. The XO 1.5's firmware knows how to copy this to its onboard microSD. The number indicates the size of the microSD flash memory image in GB.

Earlier files

.ext3.img

raw disk image including partition table, suitable for copying onto a USB drive, see OS images for USB disks.

Historical build systems and their evolution

Pilgrim was the first build system, developed by OLPC and Red Hat, and used for OLPC's early software releases.

Puritan was developed after pilgrim started to show signs of outgrowing its design, calling for a cleaner and leaner system. However, it was never adopted officially by OLPC.

Image builder was developed as a post-processing tool to complement Pilgrim when OLPC decided to hand off part of the image customization process to deployments; it takes Pilgrim images and applies various customizations to them to produce a new output image. This started to outgrow its design when various parts of pilgrim needed to be copied into Image builder in order to be able to make more invasive customizations.

For initial software development for the XO-1.5 laptop, a desire to move to standard Fedora build tools emerged. fedora-xo was used to produce the first XO-1.5 software release, but the resultant build system was messy and left no systematic process for customizations by deployments. This lead to design goals for future build systems to balance use of Fedora build tools, organisation of OLPC's special requirements, and the ability for deployments to easily obtain and use the tool while making customizations to the image.

School Server Build Tools

See XS Building Software for details.