Recently, I found myself reminiscing about games that really stuck with me. One of those titles is Theme Hospital. Luckily, there are people with enough love for these good old games, as to make them available to be run on modern operating systems. Although GOG usually has most bases covered, Theme Hospital appears to be an exception. A GNU/Linux version is unfortunately not available, which prompted me to investigate the available ports and see if there may be a way to get them running on my machine anyhow. It turns out the MacOS package has everything we would need for just such an endeavor. After downloading the most recent PAK file (at the time of this writing theme_hospital_enUS_1_0_3_33062.pkg), we need a way to extract its contents. The container is compressed using XAR, so options are limited. Luckily, 7z does support this format.

Let's setup a temporary place for the archive contents and change the directory via
mkdir -p /tmp/theme-hospital-pak && cd /tmp/theme-hospital-pak. Now we can extract the contents via 7z x ${HOME}/theme_hospital_enUS_1_0_3_33062.pkg, which tells 7 zip to place the contents into the directory we are currently executing this command from. The result should look something like:

-rw-rw-r-- 1 goggy  780 Oct 21 13:26  Distribution
drwx------ 1 goggy    0 Jan  1  1970  package.pkg/
drwx------ 1 goggy    0 Jan  1  1970  Resources/
-rw-rw-r-- 1 goggy  14K Oct 21 13:26 '[TOC].xml'

Now if we look into package.pkg/ we find two files:

package.pkg
├── PackageInfo
└── Scripts

The file Scripts is another archive compressed via gzip. So let's decompress via cat package.pkg/Scripts | gzip -dc > unzipped. The newly created file unzipped is another archive. It can be processed by cpio. Let's prepare a directory mkdir /tmp/theme-hospital-pak/raw and extract the raw contents into it via cat unzipped | cpio -i -D raw, after which it will tell us how many blocks it restored. Something like: 399282 blocks

Looking into raw, we find a directory called payload. In it, we can spot the actual game data, an embedded DOSBox version, as well as scripts to start the game. Since this is a MacOS package, we cannot use this version of DOSBox and need a local installation for whichever GNU/Linux flavor you are running. If we wish to start a single-player session, we'd need to make use of the core DOSBox config file, and the single player specific config file.

First, we need to change the execution environment to be the same directory as the game directory. In this case, cd /tmp/theme-hospital-pak/raw/payload/Contents/Resources. Assuming the local DOSBox installation is available in $PATH, we may now call dosbox -conf game/dosboxTH.conf -conf game/dosboxTH_single.conf.

Since I thought this process might as well be documented in code, I came up with a tool called goggy. It allows you to do this process with the aforementioned classic Theme Hospital and any other game packaged in a similar way. Check out the source code at https://github.com/BlurryRoots/ws-goggy and have a great time looking after those patients in need of assistance.