access memory ram 414 among other things rom 416 supports the basic input output system bios ram 414 includes dram dynamic random access memory system memory and sram static random access memory external cache i o adapter 418 allows for an interconnection between the devices on system bus 412 and external peripherals such as mass storage devices e g a hard drive floppy drive or cd rom drive or a printer 440 a peripheral device 420 is for example coupled to a peripheral control interface pci bus and i o adapter 418 therefore may be a pci bus bridge user interface adapter 422 couples various user input devices such as a keyboard 424 mouse 426 touch pad 432 or speaker 428 to the processing devices on bus 412 display adapter 436 supports a touch screen display 438 for acquiring touch data according to embodiments of the present invention display 439 which may be for example a cathode ray tube crt liquid crystal display lcd or similar conventional display units display adapter 436 may include among other things a conventional display controller and frame buffer memory data processing system 400 may be selectively coupled to a computer or telecommunications network 441 through communications adapter 434 communications adapter 434 may include for example a modem for connection to a telecom network and or hardware and software for connecting to a computer network such as a local area network lan or a wide area network wan cpu 410 may comprise a vlsi chip that has a trace array and associated circuits according to embodiments of the present invention logic signals of circuits being debugged are directed to a buss coupled to the input of trace array 307 and states of the input logic signals 305 may.