50 years ago, CP/M started the microcomputer revolution

For a quintessential CP/M experience, run it on an S-100 -based system [0] with either an Intel 8080 or Zilog Z80 CPU and some expansion cards that complete the system. Probably at least light I/O (incl. keyboard), disk storage, and graphics.

A tremendously great thing about these systems is that within a mere few years, 1 person can learn and understand the system in its totality, everything from basic electronics, circuit boards, power supply, through digital logic and components, OS and system, and up to user apps. There was a vibrant community of people making and contributing to these ecosystems, with complete systems, individual cards, upgrades and improvements, software, magazines, trade shows, and meets. Today we can recognize that as a nascent incarnation of the FOSS / commercial spectrum.

To me, it says something beautiful about the human spirit and condition. And how we are inexorably destined as a technological species. Perhaps all life capable of it is. OK I'm off to re-watch The Expanse now.

[0] http://cpmarchives.classiccmp.org/cpm/mirrors/www.s100comput...

When I got into CP/M in the 80s on my Amstrad 464, it felt like a "professional" operating system compared to those BASIC prompt ones.

Earlier this year I setup a CP/M emulator, in golang:

https://github.com/skx/cpmulator/

It got some discussion here:

https://news.ycombinator.com/item?id=40400635

I think the project is "done" for the moment, in the sense that it seems to run everything I've tried. But never say never, I had a lot of fun running real CP/M on a Z80-based single-board computer, and having a quick emulator helps me test things too. The best of both worlds.

I wrote this and submitted it last week.

https://news.ycombinator.com/item?id=41137490

And 35 years ago I banged out a concept piece on MSDOS/Turbo Pascal that was terminate-stay-resident (with a purchased development kit) I had originally coded in native 8086 under CP/M. Config a list of wildcards and enter a key at runtime, and matching files are transparently encrypted when written and decrypted when read, using hooks into DOS calls.

It worked well even with word processors of the time because even their temp files could be matched for encryption too.

But I was too serious about security and the concept used fast snake oil to test the idea, and my attempt to implement even single DES gobbled so much CPU and real time it would have been a disaster product for a 'transparent' solution.

And key/passphrase checking and features to prevent corruption of encrypted data (like an encrypted state flag!) would have required ghosting and protecting files and lots of out of band data store. The original concept was "everything in-place just encrypted" and it was fun and it worked for me. But I decided to save my sanity and stop at fun.

I eventually lost my sanity but for other reasons.

Also to note, PL/M had notion of strings and arrays length, in a 8 bit environment!

except it really isn't an operating system - i used it back in the 1980s, and it is really just a static library you can call into - same as msdos. there is no OS process running things.