I'm new to this, so I did a little research. Referring to Novell's CNE Study Guide (ISBN 0-7821-1502-0), p.815-817: "Bus Mastering allows cards within the server to communicate directly with each other without interrupting the CPU." I gather that this is NOT available on 8/16-bit ISA bus, but IS possible on 32-bit EISA, MCA, PCMCIA, VESA local bus, and apparently PCI bus. BIOS settings may determine whether a given system permits it. Boyd Ramsay [log in to unmask] PCBUILD mailing list is brought to you by: The NOSPIN Group http://nospin.com