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A Method to Allow an Infinite Number of PCI ROMs to Execute in a Constrained Memory Environment

IP.com Disclosure Number: IPCOM000033490D
Original Publication Date: 2004-Dec-13
Included in the Prior Art Database: 2004-Dec-13

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On current xSeries servers, current PCI specification and chipset technology requires that all PCI/PCI-X/PCI express ROMs reside and execute in the 0xC000-0xD000 memory segments. When this limit is exceeded, the system POST/BIOS firmware will generate a "1801 PCI Error" indicating that all ROM space has been exhausted, and subsequent devices in the boot sequence may or may not function. As seen on scalable systems such as the x445, a system may have as many as 48 slots (8 way partition with two RXE expansion units), which will easily exceed the 128 KB available memory in most configurations. This problem is forcing the customer to tailor the system to their configuration, disabling unused devices and/or defining a strict boot order based on installed adapters. What is needed is a method to allow an unlimited amount of PCI device ROMs to execute while not forcing the end user to modify the system configuration.