> For the complete documentation index, see [llms.txt](https://yenkang-2.gitbook.io/daily-discussion/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yenkang-2.gitbook.io/daily-discussion/078ch5-control-flow-checking.md).

# \[078]Ch5-Control Flow Checking

## \[078]Ch5-Control Flow Checking

* 本章最重要的兩個concept是，“heart beats”與 **“watchdog timer”**的機制，使得system能夠定時地去monitor相關指令的執行。
* 期末考題是，描述adaptive heartbeats, smart heartbeat, watchdog timer的mechanism

### Heart Beats

* adaptive與原始的差別是在於，前者的time-out period是變動的，可因network有所調整，而smart heartbeats是需要做**verify a pre-defined check** 

### Watchdog Timer

* 能夠branch verification/ Path signature的techniques做對系統的偵測，有意思的是如何對眾多的**instructions**做**"分群"**，化作graph representation, 目的是用更高level去看整個control flow的架構
* 順帶一提的是，我找到***CERBERUS-16/ An architecture for a general purpose watchdog processor*** 這篇論文，網路上都找不到數位版，最後透過學校***RapidILL館合申請***來找到紙質版，儘管找的過程花費我很多心力，但完成後卻很有成就感。