What's difference between UDMA and ATA hard disk?

I plan to use computer to edit video from my camcorder. But with my current PC, the video looks flicking. The software says that UDMA hard disk is recommended. What's different between UDMA and U-ATA hard disk? It is a special one? do you have any suggestion for this purpose?

Thanks,

Frank

They are basically the same. UDMA was introduced with the 33 Mhz interface, but then people started calling it ATA66 and ATA100 again.

If your video flickers, the reason could be the hard-disk or the cpu or the memory bandwidth. For video-editing people used to recommend using SCSI discs (incompatible with ATA), but nowadays ATA discs (also called IDE) are fine for that task. To get maximum performance, get two identical fast harddrives, buy a RAID card (if your motherboard doesn't have on-board RAID) and put the two discs into RAID0.