Adaptec 1744, AHA-1740A Multiple Host Adapter Support, Chapter Four, Standard Mode, Enhanced Mode

Chapter Four

Multiple Host Adapter Support

The AHA-1740A/1742A/1744 supports more than one host adapter in the system. The maximum number of host adapters supported depends on the operating mode of the host adapter.

Standard Mode

An EISA system can support up to a maximum of four AHA- 1740A/1742A/1744 adapters in standard mode; limited by the four available DMA channels: 0, 5, 6 and 7. The host adapters must be set to unique Interrupt channels (IRQ), DMA channels, I/O port addresses, and BIOS addresses.

Enhanced Mode

An EISA system supports up to a maximum of twelve AHA-1740A/1742A/1744 adapters in enhanced mode; limited by the number of available EISA bus master supporting slots. Each AHA-1740A/1742A/1744 installed in enhanced mode by default shares IRQ 11. This value can be changed with the MCS EISA Configuration utility by selecting the Host Adapter Interface Mode and pressing Cntrl + R key combination to view system resources (see Figure 3-3). Each AHA-1740A/1742A/1744 can be set to a unique IRQ to maximize system performance. The IRQ cannot be changed with the AMI EISA Configuration utility (cfg.exe) or the Phoenix EISA Configuration utility (ptlecu.exe).

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