john-carmack-plan-archive VS DOOM

I had to laugh at this https://github.com/ESWAT/john-carmack-plan-archive/blob/mast...

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Yes! Here is the .plan file where Carmack announces its development.

there are a bunch of features in slack beyond the core chat stuff, like:

1. being connected to multiple communities and switching between them instantly

this can be of course simply replaced by connecting to different servers in a tabbed terminal and use the terminal's built-in cmd-1/2/... shortcut, which happens to be the same as in slack.

2. meta data about others, like their timezone or how to pronounce their name is quite important for distributed team work

this can be approximated by a world readable file on the chat server in every user's home, like .plan or motd files (https://github.com/ESWAT/john-carmack-plan-archive)

3. automatic idleness detection

im actually not sure how reliable is this even in slack, but in general, it can be useful, but im not sure how to solve it elegantly, when the chat runs remotely...

maybe we should just spawn a loop at the background, which gathers idleness status from the OS and uploads it when it changes, into world readable files and the remote clients can just check those file whenever they want.

4. extra status indication with automatic expiry, eg when someone is away from the keyboard, coz they are having lunch

we do use this feature often and it's a really helpful regarding when can we expect a response from someone.

again, quite simple to model this as a plain text file and we can even use emojis, to have a very similar effect to setting " lunch" on slack. ppl would need to know what's the emoji selector shortcut though... like cmd-ctrl-space on macos.

5. text search across all channels/rooms

assuming the chat is being logged into files, then a recursive (rip)grep could work to some extent, but then from the search results one might want to get back to the context of the result too.

6. threads

this complicates implementation a lot more, but we found it an obvious improvement over the single threaded IRC model of communication

7. having threads open on the side, so ppl can track 2 streams of comms at once at least

it would require starting the chat app multiple times and do some window management to see them side-by-side

now obviously all this can be done a lot simpler, but those implementations typically always lack somehow. not sure why is that...

see https://cancel.fm/ripcord/ or http://www.altme.com/what.html

the REBOL 3 programming language even had a quite full featured, text-mode chat built in:

I was impressed by his concise daily planfiles.

https://github.com/ESWAT/john-carmack-plan-archive/tree/mast...

Quake and id Software were pioneering things we just take for granted now.

I remember playing QuakeWorld when it came out, on Linux, over a dial up modem. You had ping times of 200-300ms and it was playable. You have to remember at the time Doom and other games were LAN-only. John Carmack used to keep a .plan file with some really cool details behind Quake/QuakeWorld development. Check out Aug 02, 1996 for some detail behind the netcode[1]. You can read the future of gaming being invented right there.

[1] https://github.com/ESWAT/john-carmack-plan-archive/blob/mast...

Perhaps relevant to link to an archive of his .plan files hosted on github: https://github.com/ESWAT/john-carmack-plan-archive/

Instead, you might be interested in looking through John Carmack's .plan archive.

https://github.com/ESWAT/john-carmack-plan-archive/blob/mast... is interesting. It transitions from todo list to a narrative format right after Quake launches :) In subsequent years you see Carmack opine on various high-perf platforms for gamers, and also for Quake level pre-processing (engine licensees had money to spend on productivity)

Chapter 64 onwards of https://www.jagregory.com/abrash-black-book/ is Mike Abrash's detailing of Quake's development.

(tl;dr - Quake was developed on NeXTSTEP + an MS-DOS port of GCC (DJGPP), Quake2 was on Visual Studio + Windows (this was the era of that Carmack giant-monitor photo), there was an in-between period of free updates to the original Quake, like WinQuake, QuakeWorld and glQuake).

commercially exploit or use for any commercial purpose."

[1] https://github.com/id-Software/DOOM/commit/4eb368a960647c8cc...

The original Doom had third-party audio playback routines, so the source came with a rewritten sound server: https://github.com/id-Software/DOOM/tree/master/sndserv

    The bad news:  this code only compiles and runs on linux.  We couldn't

Here's a repo for you with no test coverage and no auto-generated DI. They using unsafe pointers all over the place, too!

https://github.com/id-Software/DOOM

Shall I prepare the postage for the letter in which you'll call John Carmack an MBA? Should we send another to Chris Sawyer? I heard he didn't even write a formal design doc for Roller Coaster Tycoon!

cURL is one of the most used C libs and is an example of good quality C code. If you follow the style used there, see e.g. https://github.com/curl/curl/blob/master/lib/dynhds.h (and associated dynhds.c) you will be good.

Looking at the source of some of the old game-engines from the era that have since been released as open-source can also be helpful, like https://github.com/id-Software/DOOM.

In both cases notice how simple and elegant a lot of the code is. There is already enough complexity inherent in the problem they are solving, and that is where the focus should be.

Any IDE with a working language server to make it easy to jump around and refactor should work fine. Limitations might be due to the C language itself?

Error handling on such a fixed platform does not need to be super-advanced. You should always be within the confines of the system so there shouldn't be much that can go wrong. If stuff goes wrong anyway just being able call a function Fatal("FooBar failed with code 34") when unexpected stuff happens and have it log somewhere to be able to dig around should be enough. You never need to be able to recover and retry.

Make sure to use https://clang.llvm.org/docs/AddressSanitizer.html or a similar tool when developing outside of the PSOne.

That said, consider statically allocating global buffers for most stuff and avoid using the heap for most stuff.

Good luck working within the confines of the PSOne! Many hackers have pulled the hair from their head on that platform ;)

Probably more easily than you'd think. DOOM is open source[1], and as GP alludes, is probably the most frequently ported game in existence, so its source code almost certainly appears multiple times in GPT-4's training set, likely alongside multiple annotated explanations.

[1] https://github.com/id-Software/DOOM

I'd define an arena as the pattern where the arena itself owns N objects. So you free the arena to free all objects.

My first job was at EA working on console games (PS2, GameCube, XBox, no OS or virtual memory on any of them), and while at the time I was too junior to touch the memory allocators themselves, we were definitely not malloc-ing and freeing all the time.

It was more like you load data for the level in one stage, which creates a ton of data structures, and then you enter a loop to draw every frame quickly. There were many global variables.

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Wikipedia calls it a region, zone, arena, area, or memory context, and that seems about right:

https://en.wikipedia.org/wiki/Region-based_memory_management

It describes history from 1967 (before C was invented!) and has some good examples from Apache ("pools") and Postgres ("memory contexts").

I also just looked at these codebases:

https://github.com/mit-pdos/xv6-public (based on code from the 70's)

https://github.com/id-Software/DOOM (1997)

I looked at allocproc() in xv6, and gives you an object from a fixed global array. A lot of C code in the 80's and 90's was essentially "kernel code" in that it didn't have an OS underneath it. Embedded systems didn't run on full-fledges OSes.

DOOM tends to use a lot of what I would call "pools" -- arrays of objects of a fixed size, and that's basically what I remember from EA.

Though in g_game.c, there is definitely an arena of size 0x20000 called "demobuffer". It's used with a bump allocator.

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So I'd say

- malloc / free of individual objects was NEVER what C code looked like (aside from toy code in college)

- arena allocators were used, but global vars and pools are also very common.

- arenas are more or less wash for memory safety. they help you in some ways, but hurt you in others.

The reason C programmers don't malloc/free all the time is for speed, not memory safety. Arenas are still unsafe.

When you free an arena, you have no guarantee there's nothing that points to it anymore.

Also, something that shouldn't be underestimated is that arena allocators break tools like ASAN, which use the malloc() free() interface. This was underscored to me by writing a garbage collector -- the custom allocator "broke" ASAN, and that was actually a problem:

https://www.oilshell.org/blog/2023/01/garbage-collector.html

If you want memory safety in your C code, you should be using ASAN (dynamically instrumented allocators) and good test coverage. Arenas don't help -- they can actually hurt. An arena is a trivial idea -- the problem is more if that usage pattern actually matches your application, and apps evolve over time.

Doom