• Software Layers to and from Hardware.
  • Applications call functions in libraries.
  • Some functions invoke Kernel System Calls. Screenshot_20240317_093409.png
  • Some system calls interact with hardware.
  • Can find out information about HW on the system with lshw and lspci.
  • lsub and lsbk
  • lscpu and lsdev
  • Can do disk benchmarking with hdparm.
  • Can configure the hardware in software with Write (echo) to proc, devor sys files.
  • Legacy devices such as keyboards are on a different bus. I/O bus.
    • Can read and write bytes to the buses. Those are inb and outb
    • Disable the keyboard by writing a value with the outb command for example.
    • Can read in items with the inb command (serial devices)
  • Can configure and change information with the setpci command.
  • Interestingly if you run lsusb, all Intel device start with 8087 in their ID. 
    Bus 002 Device 002: ID 8087:8000 Intel Corp. Integrated Rate Matching Hub
  • PCI devices, they have 8086 for Intel devices.
  • A lot of companies will use the same underlying chip in their mouse and keyboards for example.
  • lscpu, you a field called BogoMIPS. This isn’t real MIPS and is for Bogus MIPS.
    • When the Kernel boot, it has a loop and measures performance. Use the BogoMIPS to calculate how long it takes to run certain tasks.

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