jock: jock; a man with a muscular/athletic body who is typically into fitness
fdatasync instead of fsync. Data-only sync wihtout metadata journaling saves measurable time per commit. The reimplementation uses sync_all() because it is the safe default.
，这一点在新收录的资料中也有详细论述
效率的提升，并不是少写了代码，而是减少了反复试错和信息查找的时间。。新收录的资料对此有专业解读
So, let’s assume you want to have all possible RGB colors. Now we have to get a bit fancy; technically, you can edit any byte of memory at any time, but let’s say you want to keep your edits to the vertical blanking interval, avoiding any risk of screen tearing.