B.1 Ubuntu Installation

Using an Ubuntu package manager, you can add Birchwood Abbey to your list of package sources and install or update Scheme and its plugins just like other packages.

You would begin by installing the GPG key used to sign the packages. It is available at this URL:

https://birchwood-abbey.net/codemaster.txt

You should save the page, e.g. as codemaster.txt in your downloads folder, then install the key with the apt-key command.

sudo apt-key add ~/Downloads/codemaster.txt

Next add the repository to your list of package sources. On Ubuntu 18.04 you would use this command:

sudo add-apt-repository \
    "deb http://birchwood-abbey.net/ubuntu/18.04/ birchwood main"

or by editing files in /etc/apt/.

Finally, use your package manager to update its list of available packages and choose the Scheme plugins you would like to install. Scheme itself will be automatically selected because all of the plugins depend on it. You might choose the mit-scheme-pucked-x11-screen plugin because it depends on Scheme and Edwin and makes Scheme a graphical X11 application like the original MIT/GNU Scheme. You could do this with Apt by entering the following commands.

sudo apt update
sudo apt install mit-scheme-pucked-x11-screen

Note that the Ubuntu version number is part of the source URL. This allows new versions of Scheme and its plugins to be provided for old versions of Ubuntu. (Normally you would upgrade to new versions of Ubuntu to get new versions of Scheme.) However this means there may be four packages named mit-scheme-pucked with the same version, each compiled for Ubuntu 16.04, 18.04, 19.04 and 19.10.

When you upgrade to a new version of Ubuntu you should first remove the mit-scheme-pucked package (which will remove all of its plugins), then re-install them after changing the source URL (e.g. to http://birchwood-abbey.net/ubuntu/19.10/).

sudo apt remove mit-scheme-pucked
sudo add-apt-repository -r \
    "deb http://birchwood-abbey.net/ubuntu/19.04/ birchwood main"
sudo add-apt-repository \
    "deb http://birchwood-abbey.net/ubuntu/19.10/ birchwood main"
sudo apt update
sudo apt install mit-scheme-pucked-x11-screen

You can also download the package files and install them by hand. Links to the files can be found on the project home page.

https://birchwood-abbey.net/~puck/Scheme/

You will need to know your Ubuntu version (e.g. 19.10) and Debian machine architecture (e.g. amd64), then click on the corresponding link. You will need to do this for your chosen plugin, all of the plugins it requires, and Scheme itself (the mit-scheme-pucked package).

For example if you want Edwin to display in an X11 window you will want to install the x11-screen plugin which requires the edwin plugin which requires several more. Each entry on the project home page lists the package files available for a plugin and all of its required plugins.

If you would like to verify that the downloaded files are authentic you will need the corresponding .changes files. Each contains checksums for the package files and is signed. If you saved Puck’s GPG key in ~/Downloads/codemaster.txt, you can add it to your keyring like this:

gpg --import ~/Downloads/codemaster.txt

Then verify the signature on the .changes file like this:

gpg --verify ~/Downloads/mit-scheme-pucked_10.1.20-1_amd64.changes

And compare the checksum in the .changes file to one computed from your downloaded file.

grep mit-scheme-pucked_10.1.20-1_amd64.deb \
     mit-scheme-pucked_10.1.20-1_amd64.changes
sha256sum mit-scheme-pucked_10.1.20-1_amd64.deb

After you have downloaded and verified all of the required files, you can install them, required packages first, e.g. starting with mit-scheme-pucked and finishing with mit-scheme-pucked-x11-screen.

P=~/Downloads/mit-scheme-pucked
sudo dpkg --install ${P}_10.1.20-1_amd64.deb
sudo dpkg --install ${P}-gdbm_1.0.6-1_amd64.deb
sudo dpkg --install ${P}-blowfish_1.1.6-1_amd64.deb
sudo dpkg --install ${P}-edwin_3.117.7-1_amd64.deb
sudo dpkg --install ${P}-x11_1.3.4-1_amd64.deb
sudo dpkg --install ${P}-x11-screen_1.0.6-1_amd64.deb

As mentioned above, when you upgrade to a new version of Ubuntu you should first remove the mit-scheme-pucked package (which should remove all of its plugins), then install the packages built for your new Ubuntu.