IBM A40P TYPE 6841, A40I TYPE 2271, A40 TYPE 6840 manual ROM and RAM Addresses

ROM and RAM Addresses

Adapter cards with processors can contain RAM and ROM. If the adapter cards have onboard memory, then the following are true.

vROM contains operating instructions for the adapter I/O.

vRAM is used for buffering.

Two adapters using the same memory area will cause a failure. This failure might appear as a hardware failure.

The IRQ levels, DMA channels, I/O address, and ROM and RAM addresses all become potential conflicts and system problems. When conflicts arise, they might show up as system hangs, lost or missing devices, incorrect or bad data, or failing diagnostics. Always eliminate conflicts in these areas before replacing any hardware components.

Chapter 10. Related Service Information 133