I used not to care about parallelizing small programs because I thought parallelizing them would cost me more time than writing the programs themselves, and also because there are only four cores on my laptop. Unless the task were IO intensive, I would leave it running with a single thread. Everything has changed since I have access to a machine with 32 cores and 128GB memory. Looking at all those idle cores from
htop, I felt the urge to utilize them. And I found it’s super easy to parallel a Python program.
When a program crashes, you’ll see error messages like
Segmentation Fault. You might also see
(core dumped)as well. I used to feel annoyed when I saw those words because the program crashed. When I was an intern at Tianrang Networking Inc. this summer, I watched my colleague Wengong Jin work on C++ programs. Then realized that I should be glad to see
(core dumped)because the core dump file keeps all runtime information at the moment the program crashes, including data in memory, threads, stack traces, registers, and so on. It should be helpful for locating the bug.
Yesterday I saw a post on Zhihu, the Chinese Quora, asking why some popular websites adopted QR code as the default login method and also the security concerns behind it. I didn’t see an answer that truly answers the question, so I decided to speak out my thoughts.
If the following reasoning doesn’t interest you, you might also jump to the “Conclusion” section.