John Carmack's arguments against building a custom XR OS at Meta

I've written a lot of low level software, BSPs, and most of an OS, and the main reason to not write your own OS these days is silicon vendors. Back in the day, they would provide you a spec detailed enough that you could feasibly write your own drivers.

These days, you get a medium-level description and a Linux driver of questionable quality. Part of this is just laziness, but mostly this is a function of complexity. Modern hardware is just so complicated it would take a long time to completely document, and even longer to write a driver for.

Intel still does it. As far as I can see they're the only player in town that provide open, detailed documentation for their high-speed NICs [0]. You can actually write a driver for their 100Gb cards from scratch using their datasheet. Most other vendors would either (1) ignore you, (2) make you sign an NDA or (3) refer you to their poorly documented Linux/BSD driver.

Not sure what the situation is for other hardware like NVMe SSDs.

[0] 2750 page datasheet for the e810 Ethernet controller https://www.intel.com/content/www/us/en/content-details/6138...

Wow... that PDF is 2,750 pages! There must be an army of technical writers behind it. That is an incredible technical achievement.

Real question: Why do you think Intel does this? Does it guarantee a very strong foothold into data center NICs? I am sure competitors would argue two different angles: (1) this PDF shares too much info; some should be hidden behind an NDA, (2) it's too hard to write (and maintain) this PDF.