RPM(Redhat Linux Packet Manager)是Red Hat公司随Redhat Linux推出了一个软件包管理器，通过它能够更加轻松容易地实现软件的安装。
Like bochs, QEMU emulates an x86 CPU. But QEMU is much faster than bochs as it uses dynamic compilation. Bochs is closely tied to x86 PC emulation while QEMU can emulate several processors. Like Valgrind, QEMU does user space emulation and dynamic translation.
Accesses made using either access mechanism are equivalent. The PCI Express Extended Configuration Space can only be accessed by using the ECAM.
On x86 and x64 platforms, the address of each memory area is determined by the ACPI ‘MCFG’ table.
chroot，即 change root directory (更改 root 目录)。在 linux 系统中，系统默认的目录结构都是以 /，即以根 (root) 开始的。而在使用 chroot 之后，系统的目录结构将以指定的位置作为 / 位置。
The newest kernels have moved the video mode setting into the kernel. So all the programming of the hardware specific clock rates and registers on the video card happen in the kernel rather than in the X driver when the X server starts.. This makes it possible to have high resolution nice looking splash (boot) screens and flicker free transitions from boot splash to login screen. Unfortunately, on some cards this doesn’t work properly and you end up with a black screen. Adding the nomodeset parameter instructs the kernel to not load video drivers and use BIOS modes instead until X is loaded.
The splash (which eventually ends up in your /boot/grub/grub.cfg ) causes the splash screen to be shown.
At the same time you want the boot process to be quiet, as otherwise all kinds of messages would disrupt that splash screen.
- Options in
GRUB_CMDLINE_LINUXare always effective.
- Options in
GRUB_CMDLINE_LINUX_DEFAULTare effective ONLY during normal boot (NOT during recovery mode).
TCC makes sure each device executes its operations exactly when it supposed to.
Lockstep systems are fault-tolerant computer systems that run the same set of operations at the same time in parallel.
COLO (COarse-grained LOck-stepping)是一种虚拟机的高可用解决方案。当启用的COLO功能后, 主虚拟机(PVM)和备虚拟机(SVM)都会同时处于running 状态。PVM和SVM都可以接收到来自client的网络数据包, 并对数据包做出回应。当PVM和SVM回复的数据包的内容相同, 则PVM回复的数据包会返回给client, 否则会触发checkpoint对PVM和SVM进行同步，然后再将数据包返回给client。当PVM所在的物理机发生宕机时候, SVM可以立即接管, 为client提供服务。