It is hardware access.
Mostly, it has to do with graphics.
However, sound cards are also added to the list of hardware.
OpenGL is other standard for graphic Hardware access, DirectX is Micrsoft's version of it. Just like Virtual Java Machine is Microsoft's verison Java by SUN. Microsoft has to get their hands into everything.
Soyo Dragon Ultra Platinum Edition powered by a P4 3.06GHz w/HT @ 533FSB
ATI Radeon X800Pro 256DDR <---Yeah!!! I finally got it!!!
1024MB PC3200, Creative Audigy LS, 2 x 40GB = 80GB RAID 0
Windows XP Pro, DOOM 3, CS, UT2004, BF1942 RtoR, CNC Generals
Finished Half-Life 2!!!!!!!!!!