Thoughts & Question about converters.

Ok its been several years since I had converted my site to IPB

Since my site has been operating since 1997 i have gone thru several different forums

started out with a CGI Script then converted to forum with SQL.

Each upgrade or lateral change to another forum used the "IDs" that were already established

But when i converted to IPB the converter created a join table between the OLD of the

old forum and the NEW ID's of IPB. And in order to survive the transition i have to add some

scripts to my site root of a few php files that match the old forms.

The job of these are to map the old url to the new url.

Please forgive me if I don't totally grasp the concepts but here are a few lingering thoughts...

As a converted site I always will have to maintain the converter APP in my ACP if i were to remove it

it would delete the associated join table. Breaking all legacy links.

Why do i have to maintain the OLD forum php scripts - couldn't a mod rewrite capture any known formats

and then redirect to a IPS single php script buried somewhere else that would use the join table to ultimately

take the user to the intended link?

Aside from perhaps a very old cached link from an google search would still map to the OLD url

there are a lot of links inside the body content of the forums of other posts that others have made

but they themselves may contain the OLD forum format. - I would have thought the conversion script

would have been smart enough to loop thru all body content of threads and do some regular expression

to convert all OLD forum links to the NEW IPB links.

If my site was internally using all self referencing IPB links then eventually the JOIN file and conversion app could

be deleted?

why use a JOIN file - why wasn't there just a field or so in the tables that reference the OLD conversion path & id

then before it presents a 404 query the url string against the threads that were legacy?

Again forgive me if I am being overly simplistic but I wish to further understand this.