2.3. Bus Mastering

The next step in server evolution was bus mastering technology, as illustrated in Figure 2-3.

Figure 2-3. Bus mastering.

With bus mastering, multiple bus master devices contended for access to system memory. Multiple processors could transfer data directly to main memory. I/O adapters could also transfer data directly to main memory.

Although enabling I/O devices to be bus masters freed up processor resources, it caused contention for memory.