Such an inspiring read! Thanks for writing and/or sharing. One of my many future hermit projects is to hack on an early version of Linux. ------------ Please i

Such an inspiring read! Thanks for writing and/or sharing. One of my many future hermit projects is to hack on an early version of Linux. ------------ Please ignore just jotting down for future myself --------------- (Actually I want to study Win NT more than Linux as it brought me good memories, but Win NT was designed as a mature product from the beginning, and even the leaked 3.5 source code is way too much for me.) I checked the version history and 0.11 seems to be a good start. Reasons: - There is this book (https://download.oldlinux.org/ECLK-5.0-WithCover.pdf https://download.oldlinux.org/ECLK-5.0-WithCover.pdf) which follows the style of Lion's Unix v6 book and uses the 0.12 kernel as reference; - 0.11 doesn't have a virtual memory or a virtual terminal, and they are among the software I'd like to implement; - 0.11 does have the basic stuffs so I assume it is not too difficult to set it up with QEMU and QEMU-gdb; The list of software to implement in mind: - a Debugger (I'll probably use QEMU-gdb, but if I can write a simple step-in debugger maybe it makes it a bit easier to dogfood? Still too early though as there is no compiler on it) - a Virtual Memory system (following the MIT xv6 lab, maybe a bit more advanced as I will complete the MIT xv6 labs before pursuing this venture); - a Virtual terminal (not sure how much I can implement, maybe just a basic one with limited control sequence support); - a USB driver (not sure if it's possible for 0.11, I have never written a driver before); - a mouse driver (again probably too difficult for me); - a LOT of CLI programs as warm-up. Basically simpler versions of modern ones (less switches); - a text editor. I never liked the key layout of emacs or vim so this is going to be my own thing. I care a lot about moving caret around without using a mouse; - a very basic GUI system. Nothing fancy, just something that can show windows and some widgets. Maybe don't even care about multiple windows. Showing one window with a menu and some buttons probably needs a lot of effort; - a compiler/linker of a simple language (can't dogfood without an editor, a compiler, a linker and a debugger I think) Preparations: - I need to complete all MIT RISC xv6 labs; - I need to figure out how to write drivers for USB and mice; - I want to investigate how X11 and Win32 GUI were implemented and figure out the architecture; - I need to figure out how to write terminals and text editors. There are tons of tutorials online so shouldn't be too tough; - I need to study compiler theory, just continue reading Crafting Interpreters should be good enough; - I need to figure out a comfortable development and debugging environment;