In the exemplary embodiment, data processing system 100 includes a graphics adapter 104 also connected to system bus 108, for providing user interface information to a display 106.Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.).
![]() Rom Expander Code Is StoredThe executable boot code is stored on a Read Only Memory (ROM) on each peripheral device.When a new PCI peripheral device begins to boot up, a check for available memory space in a ROM scan memory address space is performed. If there is not enough available room in the ROM scan memory address space for the new devices executable boot code, then a ROM scan detection logic pages an image of another peripheral devices executable boot code out of the ROM scan memory address space before storing the new devices executable boot code into the ROM scan memory address space. Still more particularly, the present invention relates to a method and system for initializing an add-in peripheral device without being limited to available memory in a dedicated boot memory address space. One method known to add on such a peripheral device is to plug the peripheral device into a physical socket on a motherboard in the computer. Once the peripheral device is plugged in, the computer learns about the existence of a Read Only Memory (ROM) that is on the peripheral device. The information stored on the option ROM includes code which can initialize the peripheral device during a Power On Self TestBasic Input Output System (POSTBIOS) initialization performed by the computer during power on or a soft start. The option ROM described above on the peripheral device that connects to the PCI bus is called a PCI ROM. This address space is traditionally between C0000 hex (C0000h) and DFFFF hex (DFFFFh), and is accessible only for booting peripheral devices. The total memory space between C0000h and DFFFFh is 131,072 dec bytes (128 KB). However, modern computers, and particularly servers such as the xSeries manufactured by IBM, provide 4 to 6 expansion slots on a PCI bus. All of the expansion slots may be fully populated with adapter cards for multiple purposes, such as Management Processsors, Network Cards, or InputOutput (IO) cards, including cards for devices such as a Redundant Array of Inexpensive Drives (RAID) mass storage device. Each of these adapter cards can contain up to 64 KB of BIOS or embedded code that must run in the memory address space between C0000h and DFFFFh. Therefore, some of the PCI devices must either be disabled, or even physically unplugged from the PCI bus, in order to avoid an 1801 PCI Error, which indicates that all of the space between C0000h and DFFFFh has been taken up by other PCI ROMs. If additional PCI devices attempt to boot with the C0000h and DFFFFh space full, the boot sequence for those PCI devices will likely not execute, and those new devices will not function. Preferably, such a method and system would not require an end user to modify the computers hardware configuration, such as physically removing PCI devices according to their memory requirements and the limited address space available for add-in devices in the computers system memory. The computer system memory that is dedicated to storing the executable boot code is called the ROM scan memory address space. When a new PCI peripheral device begins to boot up, a check for available memory space in the ROM scan memory address space is performed. Data processing system 100 may be, for example, one of the models of personal or server computers available from International Business Machines Corporation of Armonk, N.Y. Data processing system 100 includes a central processing unit (CPU) 102, which is connected to a system bus 108.
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