It worked well enough and ensured the example 'grandma' problem above could not occur. The Finder maintained a 'desktop database' which, I believe, was used by

It worked well enough and ensured the example 'grandma' problem above could not occur. The Finder maintained a 'desktop database' which, I believe, was used by the operating system to determine which Applications were able to open files given their type. This was updated automagically, so given a floppy disk with an application on it, and a file that could be opened by that application, the user could insert the disk, double-click the file and the application would be launched to open the file--even if the application was previously unknown to the machine in question. Power users could use ResEdit or some other tool to change such attributes of a file. http://vintagemacmuseum.com/macintosh-type-and-creator-codes/ http://vintagemacmuseum.com/macintosh-type-and-creator-codes... has some more info about the system. Also https://tidbits.com/2009/09/06/snow-leopard-snubs-document-creator-codes/ https://tidbits.com/2009/09/06/snow-leopard-snubs-document-c... which remarks on the system's retirement in OS X 10.6. Reminiscing about all this makes me remember fondly how much better the experience of using a Mac back in the 90s was compared to computing nowadays!