But of course, like any immutable system, there are mutable parts (otherwise, we couldn’t create any configuration files). OSTree handles this with “overlays” (actually, we use OverlayFS) that allow a read-write filesystem to be layered on top of the immutable system. For example, the /etc and /var directories are writable, while the rest of the system is read-only.
它的本质，是“社区主导+专业管理”的结合——既有居民的参与和认同，又有专业医疗体系的支撑，最终实现了“老人在社区，就能享受到优质医疗服务”的目标。
，这一点在新收录的资料中也有详细论述
Why does this approach work?
以前还能一边说自己代表客户，一边又偷偷做自己的库存生意；一边拿服务费，一边再赚交易差价。这样的双重身份，往后只会越来越难混过去。