Background. We have an espresso machine in the lab and it’s perfect to start a productive day with a cup of coffee! In order to make this sustainable, we have to maintain a fund for purchasing coffee beans. Since I rarely use cash for years, I feel inconvenient to put cash in a jar for every espresso. So why not write an app to keep everyone’s account balance so that we can just click and enjoy the coffee!

Background. My backup hard drive broke last week and I lost some pretty good memories of my early software & hardware projects. I suddenly realized the importance of backup data safety. Considering several factors of the files or folders, I can determine the proper configurations of the backup: Update Frequency. Is it updated in a weekly, monthly, or yearly manner? Some ongoing git project can have daily update. Importance.