Using a virtual dispatch might get relatively expensive in terms of clock cycles due to multiple levels of indirections including indirect branching as well as this pointer adjustment. Wise programmers do not use virtual dispatch without a good reason but oftentimes it is required either by design or when creating non-template reusable components/libraries and the final implementation of some parts of the program is not known.

Back in the day, I was reading a book about UNIX® programming and have learned how to write a signal handler. It was a long time ago and I don’t remember the book, but to this day the way described in that book is something that shows up in Google’s top results when you search for “How to write a signal handler”. Here it is — a simple, elegant solution to the world’s toughest problem:

Hard disks: if you read this, it's pretty much certain you use one or more of the things. They're pretty simple: they basically present a bunch of 512-byte sectors, numbered by an increasing address, also known as the LBA or Logical Block Address. The PC the HD is connected to can read or write data to and from these sectors. Usually, a file system is used that abstracts all those sectors to files and folders.

If you look at an HD from that naive standpoint, you would think the hardware should be pretty simple: all you need is something that connects to a SATA-port which can then position the read/write-head and read or write data from or to the platters. But maybe more is involved: don't hard disks also handle bad block management and SMART attributes, and don't they usually have some cache they must somehow manage?

All that implies there's some intelligence in an hard disk, and intelligence usually implies hackability.