Why I hate software patents: IBM patents trim()(patft.uspto.gov)

  With reference now to FIG. 3, a block diagram illustrating a data
  processing system is depicted in which the present invention may be
  implemented. Data processing system 300 is an example of a client
  computer. Data processing system 300 employs a peripheral component
  interconnect (PCI) local bus architecture. Although the depicted
  example employs a PCI bus, other bus architectures such as Accelerated
  Graphics Port (AGP) and Industry Standard Architecture (ISA) may be
  used. Processor 302 and main memory 304 are connected to PCI local bus
  306 through PCI bridge 308. PCI bridge 308 also may include an
  integrated memory controller and cache memory for processor
  302. Additional connections to PCI local bus 306 may be made through
  direct component interconnection or through add-in boards. In the
  depicted example, local area network (LAN) adapter 310, Small computer
  system interface (SCSI) host bus adapter 312, and expansion bus
  interface 314 are connected to PCI local bus 306 by direct component
  connection. In contrast, audio adapter 316, graphics adapter 318, and
  audio/video adapter 319 are connected to PCI local bus 306 by add-in
  boards inserted into expansion slots. Expansion bus interface 314
  provides a connection for a keyboard and mouse adapter 320, modem 322,
  and additional memory 324. SCSI host bus adapter 312 provides a
  connection for hard disk drive 326, tape drive 328, and CD-ROM drive
  330. Typical PCI local bus implementations will support three or four
  PCI expansion slots or add-in connectors.