You're going to have a tough time with the ISAPI DLL's, in a shared environment, depending on what they are I guess.
If you email a company, you'll probably get told " yes that would be fine", without asking what exactly you are wishing to do. If you find yourself in that scenario, do yourself a favour and explore other avenues, as security it probably at a minimum.
Simply explain to a prospective hosting company exactly what your scripts and DLL's entail, and move from there.
Most Windows hosts will support cgi EXEs no problem. ISAPI support is less common, for two reasons.
First is that you need a mechanism for unloading the ISAPI DLL when you need to change it, without needing to restart IIS, which a host is not going to want to do, as that disturbs all the other customers on the server! ISAPI Manager is a good solution (free from http://www.turbodb.de/en/support/isapi.html).
Second is the issue that if your ISAPI has problems it can affect other sites on the server, so a good host will require that you properly test and debug an ISAPI before uploading it.
A good quality Windows host should be able to accommodate you; there are plenty around -- but maybe expect to pay a little more than bottom price! I'd steer clear of resellers, simply because a reseller will not usually have total (desktop) access to the server to sort out any ISAPI issues you might have, only control panel access.
In many cases, CGI exes are fine -- sure, they load and unload for each call made, but unless the site is very busy it's not an issue. ISAPIs are ideal for really busy sites. In the Delphi world ISAPIs have become more popular because of IntraWeb, which produces ISAPI DLLs.
Chris at TDMWeb.com
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