https://www.siliconvalley.com/2022/02/17/larry-magid-a-toolbox-full-of-handy-windows-and-mac-utilities/ > Around 1983, I started using a program called Sidekick, which was a bundle of handy utilities that popped up as a “TSR” (terminate and stay resident) program within MS-DOS. What was cool about it is that it worked at the same time and alongside whatever other software you were running back in the day when operating systems could run only one program at a time. > The days of TSRs are long gone, but a handy utility called Parallels Toolbox, reminds me of them in the way it provides useful functionality that you can use alongside whatever other programs you use.