The whole boot process of computer can be summarized in 4 phases.1. BIOSIn the 70's  read-only memory(ROM) was invented. The boot program is written into ROM, the first thing the computer does is to read and execute this program when it's powered on.The program in this chip is called "Basic Input/Output System" (BIOS).1.1 Power-On Self-TestThe BIOS will first check whether the computer hardware can fulfill the basic conditions for booting up, this process is called Power-On Self-Test, simplified as POST.If the hardware has problems, the mother board will produce different beeps and the bo...

Problem description:We need to access a very big table which has 40 million records. In the table, id is the primary key and program_id is indexed.When executing a select query:select * from program_access_log where program_id between 1 and 4000The above query executes very slowly, we thought it was because there were too many records in the table. So we added id in the where condition to limit the search so that each time only half a million records would be read.select * from program_access_log where id between 1 and 500000 and program_id between 1 and 4000But this query is st...