The Linux kernel is the primary virtual machine; it is invoked by the service console. At normal run-time, the vmkernel is running on the bare computer, and the Linux-based service console runs as the first virtual machine. VMware dropped development of ESX at version 4.1, and now uses ESXi, which does not include a Linux kernel.
The definition of zen is slang for feeling peaceful and relaxed. An example of zen as an adjective is to have a zen experience, how you feel during a day at the spa. Zen is a type of Buddhism that focuses on awareness through the practice of meditation. An example of Zen is a rock garden that is tended to meditate.
Psycho is a slang term for someone who is mentally unstable or afflicted with a psychosis. Your best friend risks looking like a psycho if she keeps stalking her ex-boyfriend months after their breakup. Psycho comes from the Greek word psykho, which means mental. Although the word has long been used as a prefix in words like psychologist, the pejorative term for a psychopath has only existed since the twentieth century.