The different standards arose because there are "issues" for pro audio use with the type of soundcard most machines are provided with. Apart from actual audio quality, we need to get digital audio in and out without it being altered in any way and we want it to happen quickly to hear a soft synth when we play a note on our midi keyboard.
The first thing that alters sound quality is sample-rate conversion (SRC). Consider a modern Windows pc - it can do many things at once. So the sound system can expect, at any time; Windows alerts, playback from CDs, Streaming audio off the web, Voice modems etc, all of which will have different sample rates (and bits too). You cannot mix different sample rates without converting them to a common rate. That common rate is usually 48Khz. So there has to be a digital "mixer" in the audio path. It's either in software, or implemented by the soundchip when its called a "Hardware accelerator". If a manufacturer like Creative want to claim "full hardware acceleration" for their cards, it will have to use SRC. ALL THE TIME!
A "pro" soundcard won't have SRC abilities, though many can "mix" audio with the same sample-rate (multiclient support). Windows provides a software SRC that works with WDM drivers however, and the last thing you want is that to occur which it will if you attempt to play more than one sound with different rates. The WDM driver supports two Microsoft audio protocols. MME was the first and dates back to Windows3.1, Microsoft now call MME audio "Wave". DirectX came more recently and includes DirectSound (audio) and DirectMusic (midi and audio). The WDM driver is quite recent though (Windows98SE), it was predated by a driver type called VxD.
As for timing (latency) Microsoft were slow to wake up to the problem. MME originally was a whopping 450ms. DirectSound reduced this to some 30 to 40ms. This is still enough to cause problem with games for instance, where a sound really ought to coincide with its cause.
To get around all this Steinberg proposed the ASIO driver to give audio software exclusive access to a dedicated soundcard free of any of the above issues. There was also E-magics' EASI driver, now pretty much defunct since their Logic Audio became Apple Mac only.
Enter Cakewalk. When the WDM driver was being developed, Cakewalk with others, successfully lobbied for it to allow "pro" audio support.
The driver would have low-level "kernal streaming" access points so an Audio program can bypass the software mixer with low latency (known as WDM/KS). Additionally, access was available to add on support for ASIO and others.
Many Windows PC soundcard drivers are now WDM, with ASIO etc also being included. Thanks to the WDM/KS access, any WDM driver can have ASIO added using asio4all.
There are still some that are not WDM. Digidesign have there own standard for interfaces sold with Pro Tools LE.
GigaStudio uses a "direct disk streaming" playback method. I don't know why, but they obviously felt it required yet another driver protocol. GSIF is added to WDM drivers in the same way ASIO is.
Apple are leading the way to give one driver standard that suits everyone - CoreAudio. Microsoft are going to have to do something similar eventually.
