RTFPS(4)

📦 version 11.0, in nixpkgs unstable

✨ NAME ✨

okay so welcome to rtfps(4), straight out of the Kernel Interfaces Manual, bestie 💖 This page is for rtfps — multiplexing serial communications interface. That’s the whole name vibe.

🌈 SYNOPSIS 🌈

Here’s the kernel-config moment, copied exactly because we do not mess with syntax:

rtfps0 at isa? port 0x1230 irq 10
com2 at rtfps0 slave 0
com3 at rtfps0 slave 1
com4 at rtfps0 slave 2
com5 at rtfps0 slave 3

No extra lore, just the config lines. 🫶

🦋 DESCRIPTION 🦋

The rtfps driver provides support for IBM RT PC boards that multiplex together up to four EIA RS-232C (CCITT V.28) or RS-422A communications interfaces. Four! A little friend group of ports. 💅

Each rtfps device is the master device for up to four com devices. The kernel configuration specifies these com devices as slave devices of the rtfps device, as shown in the synopsis. The port specification for the rtfps device is used to compute the base addresses for the com subdevices. That’s the mechanics, and honestly it’s giving very organized. ✨

🎀 FILES 🎀

  • /dev/tty0? — yep, that’s the filesystem moment, question mark included. 💖

🔥 SEE ALSO 🔥

  • com(4) — go read that one too, iykyk.

💜 HISTORY 💜

The rtfps driver was written by Charles Hannum, based on the ast driver. Credit where it’s due, periodt. 🫡

💀 BUGS 💀

real talk, bestie: this one has some caveats, and we are not pretending otherwise.

The rtfps driver is unlikely to work on non-EISA and non-PCI machines. The ISA bus only asserts 10 I/O address lines, and this is not enough. That’s the whole problem, no cap.

Even on EISA and PCI machines, some address conflicts have been observed. On one machine, the second port always conflicted with something (though it’s not clear what) and caused strange results. Disabling the second port in the kernel config allowed the other three ports to function correctly. So yeah, sometimes the fix is literally “turn off the second port,” which is wild but that’s what the page says. 😭

okay that’s the page, bestie. This manual page is from Debian, dated August 7, 1994, and it’s RTFPS(4) signing off. 🫶✨

📦 where this page comes from