Commissioning RACHEL

One way to get RACHEL running on a server is to simply follow the intructions to use one of the existing image files, write that image to a memory card, and boot a Raspberry Pi using that image. This may be enough for some of us. However, that RACHEL server will be a clone of one created by developers the World Possible project team, and unlikely to be ideal for our environment and context. For instance the network settings might clash with other networks in your environment; the image may be too large, etc. We can customise RACHEL servers during and after commissioning the server.

Commissioning using image files created by World Possible

The project team provide documentation online on Google Docs on how to download, install and run RACHEL as a server on Windows computers, details are available at RACHEL-Pi Download Guide

Where to find RACHEL online

One of the most reliable locations for RACHEL images is http://rachelfriends.org/

RACHEL is also available from the same site using FTP.

What’s involved to download and get RACHEL running

Here we’ll summarise the steps needed from starting the download to running RACHEL

  • Download (which can take days, and often fails part way through, so we need ways to cope with the unreliable network and Internet connections
  • Check we’ve received what was intended (by checking a calculated code called MD5 sum).
  • [Optionally] copy the downloaded file. We need plenty of space on the local drive or partition, ideally at least 3x the size of the download.
    • When dealing with image files for Raspberry Pi’s they’re created to fit on a 64GB memory card. However, 64GB is more a marketing term than a commitment the drive actually holds 64GB of materials, they often hold slightly less. A few models of memory card are significantly smaller and the image may not fit.
    • Conversely the image is smaller than many drives so there may be unused space of several GB on some memory cards. We can ‘expand’ the image once it’s been copied to the memory card so that it can use all the available space.
  • Unpack, or write the image. RACHEL contains lots of materials, which are made up of 100,000’s of files. There are so many files that some drive formats, and some unzip programs cannot cope.
  • Update, the sofftware and contents are snapshots created at some point in the past. Updating the software and contents can increase and protect the trustworthiness of the system.
  • Protect, viruses can infect most computers, and they can be stored on the memory and computers we’re using. We can use hardware and/or software to help protect the integrity of the materials and software.
  • Use, RACHEL includes software, particularly web server(s). When these are started they can unleash the full capabilities of the materials.

Writing the RACHEL Pi image to memory cards

On Microsoft Windows, there’s an excellent simple utility called Win32DiskImager which is available from http://sourceforge.net/projects/win32diskimager/files/latest/download Details of how to use this command are in the above online document.

On Linux we use the dd command to write the downloaded image to a memory card. A very clear guide is available online Installing Operating System Images on Linux

Here’s an example of writing the image where I’m using the time command to measure the duration of the write.

time sudo dd bs=1024k if=rachelpi_64EN_3.2.1.img of=/dev/mmcblk0

You probably need to revise the command line to match:

  • the input file (the if= parameter).
  • the output ‘file’ (the of= parameter) for where your computer has mapped the physical SD-card in it’s list of devices.

The write took 86 minutes! 

1 real	85m33.743s
2 user	0m0.383s
3 sys	2m2.943s
4 
5 62864228352 bytes (63 GB) copied, 5133.74 s, 12.2 MB/s

You may also need to stop your computer from using the SD-card by un mounting it, using the umount command in Linux.

For OSX there are diskutil commands. For now, please search online for instructions on how to write Raspberry Pi images when using OSX.

Configuring an existing RACHEL server

TBC for now please see the following links (from ka-lite) which cover many of the same topics

Here are the topics I want to cover in this chapter

  • network
  • server name
  • content packages
  • software packages
  • Configuring accounts in ka-lite

Up next

Introduction to the Technical User’s Guide to RACHEL