Wow...I just keep thinking how simple EVERYTHING was back in '04
Yes, it sure was but then so were so many things everywhere.
While that simple flat file management worked for a small number of assets, it made content management difficult and didn't have the capability of multiaccess among other things. There are penalties for loading up files sequentially and to get around that, then Auran implemented a MySQL database in TRS2006 which allowed for quicker, by those days standards, access to the ever-growing DLS and local downloads. Thinking about it, the sequential loading of content became a longer and longer process because the whole load of content was read from one file to another until the new content was added to the cache. A big download day from the DLS meant it took longer and longer to load in the content.
The other issue was content couldn't be installed on the fly easily and cache-files had to be deleted manually if working outside the content management system. There is a rudimentary content management system in TRS2004, but it's not exactly easy to use compared to what came later.
With TRS2006, this changed and that set the groundwork for what we have today, but it took another 5-years before we finally got multi-file access and the capability to open, read, write, and access the database at the same time. The maligned TAD Daemon was the beginning of what was to come for that, and that process has been improved. This also allows for reading content out of order which allows for quicker loading of content because instead of the content being read off the disk directly, it's referenced in a database instead. This is the feature of a relational database with records are kept in multiple smaller files and tables rather than all in a single flat file.