As of year 2004, Dr. Gary Kildall’s operating system called CP/M was approaching 30 years old. I decided then to describe that history on my Web site, before it was lost. I worked on that through 2008; and updated my notes since. See my DRI home page for links to Web pages about that event, and about about persons, companies and developments related to Digital Research and/or CP/M in the S-100 and microcomputer world of the 1970’s.
This Web page provides some ideas about how to get and “run” CP/M today, or past alternatives to CP/M, in the 21st century.
I should really set up a CP/M environment to experience what it’s like – when I first started using computers, it had already lost out to DOS.
CP/M running on an Amstrad PCW was my introduction to computers sometime in the mid-1980s. Great machines, really inexpensive, and for the price and surprisingly versatile and powerful.
https://en.wikipedia.org/wiki/Amstrad_PCW
The PCW was a bit like the early forerunner of the original iMac in that the CPU etc was all housed in the monitor case.
Z80, CP/M and 64K of usable application RAM. I can think of a few alternatives I would prefer at the time but you get what you get.
CP/M 9s quite close to DOS in it’s workings. However, it’s quite a bit different to RT-11, which was largely the inspiration for CP/M. If you truly want to experience the predecessors to DOS, RT-11 is probably the best place to start. There’s a lot that’s similar, but there’s quite a few differences too.