有人说UDMA是DMA磁盘驱动, 可文档上说是缓存程序
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UDMA is a DOS hard-disk caching driver.
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All possible I-O for SATA and UltraDMA disks goes through its XMS cache buffers, for
faster speed. UDMA calls the BIOS for diskettes and other type disks,
so it will cache ALL disks on a DOS system!