Technical Knowledge Base

lspci - devices on the pci bus. switches like -v can help
lsusb - devices on the usb bus, switches -s , -v show more info
/proc/cpuinfo - cpu infor
/proc/interrupts - list of number of interrupts per io device
/proc/ioports - io port regions in use
/proc/dma - direct memory access - lists registered DMA channels
/dev - every file inside /dev is associated with a system device, especially storage devices.