RHEL133: 3.Kernel Services and Configuration

    3.1 Kernel Modules
        Modular kernel components
            Components that need not be resident in the kernel for all configurations and hardware
                peripheral device drivers
                supplementary filesystems
            Modules configurable at load time
        /lib/modules
        Controlling modules
            lsmod查看已经装入的module,modprobe加载module
        Kernel Tainting If a module with a proprietary license is inserted into kernel,it becomes tainted
            Red Hat will not support tainted kernels
    3.2 Kernel Module Configuration
        Module examination:/sbin/modinfo 查看已装入module信息 例：modinfo ipv6会列出ipv6 module详细信息
            parameters,license
        Module Configuration:/etc/modprobe.conf 设定module载入和动作
            aliases,parameters,actions
        Module Dependencies:modules.dep,depmod   module相依性
        Manual Control:insmod,rmmod 载入/移除 module
    3.3 The /proc filesystem
        /proc is a virtual filesystem containing information about the running kernel
        Contents of "files" under /proc may be viewed using cat
        Example :cat /proc/cpuinfo 查看cpu状态
        Provides information on system hardware,netwrking settings and activity,memory usage,and more
        /proc subdirectories
            /proc/scsi/ scsi设备资料
            /proc/sys   kernel参数
            /proc/<PID> 执行中程序的资料
        The /proc/sys subdirectory allows administrators to modify certain parameters of a running kernel
    3.4 /proc/sys configuration with sysctl
        /proc/sys modifications are temporary and not saved at system shutdown
        The sysctl command manages such settings in a static and centralized fashion: /etc/sysctl.conf
            use sysctl -p views /etc/sysctl.conf
        sysctl is called at boot time by rc.sysinit and uses settings in /etc/sysctl.conf
    3.5 General hardware Resources
        dmesg and /var/log/dmesg
            kernel->klogd->ring buffer->/var/log/dmesg
            kudzu
               /etc/sysconfig/hwconf
               /usr/share/hwdata
            /proc filesystem
            hwbrowser 图形显示
    3.6 System Bus Support
        PCI Bus
            /sbin/lspci
            /proc/bus/pci/
        ISA Bus
            /proc/isapnp/
    3.7 HotsWappable Bus Support
        USB and IEEE 1394 Buses
            /sbin/hotplug,(/etc/hotplug/)
            Information in /proc/bus/ subdirectories
            /sbin/lsusb 列出usb设备
            USB devices in /dev/usb/
    3.8 System Monitoring and Process Control
        top,gnome-system-monitor display
        vmstat:reports virtual memory stats
        free: summary of system memory usage
        renice: change priority of a process renice <priority> <PID>
        kill : send system signal to a process