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Hierarchy Memory 1. Why use Hierarchy Memory Because the register memory is much faster than main memory, in fact the difference is about two magnitude. And the performance gap will be larger because the CPU’s speed increase faster than main memory. In this situation, if we fetch data from the main memory too many times, the expense will be very expensive. But if we create some memory which is faster than main memory but a little bit slower than register memory. We call it cache. ...

Several issues I meet when plug in new RTX 4090 GPU for my workstation Background hardware s AMD 7950X3D 128GB(4x32GB) DDR5 6000MHz Gigabytes X670 ATX 2TB samsung storage [Nvidia RTX 4090] Install 4090 hardware to the workstation At first, the installation is smooth, just plug the PCIE slot into the upper one is fine. However, I found I forgot to install the support for the RTX(it’s too big and heavy, definitely need the support.) ...

Problem Statement Recently When I was trying to set up an API server in a perl script to do some unit tests, I met lots of trouble. In conclusion, the trouble can be classfied as 3 parts: The residual server processes can’t be killed properly. Program stucked after launch the API server. stdin, stdout, stderr on windows. Error examples The residual server processes can’t be killed. 1 system(perl server.pl daemon -l http://*:0); Use the command above in main test script will launch an API server in a child process. The residual server processes should be killed without any left after the tests. At first I use “system” to run the command, and then kill it in a different system command via: ...

Feynman has told us the best way to learn something is that you use concise and understandable words introduce what you learned to others, if they can understand well, then you master the knowledge. I have a habit which writing some notes/docs for myself, which is hard to undetstand for others(Even myself would lost after several weeks). Then I decide to make my work/study log perfect and share what I think is valueable to others. ...