On Wed, 4 Apr 2007, Russell King wrote: > On Tue, Apr 03, 2007 at 04:09:08PM -0700, Brad Boyer wrote: > > The availability of the specific chip in question is a red herring in > > my opinion. I do understand that 8250 compatible chips are very common > > and are the most likely serial chips to be used with Linux. However, I > > will point out that the define is TTY_MAJOR, not 8250_MAJOR. It seems > > to me that whoever named it was thinking in more generic terms. > > You're reading too much into the name. It's historical, and the reason > can still be seen in LANANA: > > 4 char TTY devices > 0 = /dev/tty0 Current virtual console > > 1 = /dev/tty1 First virtual console > ... > 63 = /dev/tty63 63rd virtual console > 64 = /dev/ttyS0 First UART serial port > ... > 255 = /dev/ttyS191 192nd UART serial port > > UART serial ports refer to 8250/16450/16550 series devices. > > When the drivers/char/serial.c driver was written, it was in the very > early days of Linux. I'd guess that the major/minor numbers were similar > to Minix, thereby allowing a minixfs to be used as the initial filesystem > type. > > Anyway, as you can see, defining chardev major 4 to be "8250_MAJOR" would > also be a misnomer because it's used for the virtual consoles, and it's > _that_ use for which it (probably) was called TTY_MAJOR. > > (Note that in the very early days, this major also got used for PTY > devices. Since then they've moved to major 2/3 and then we got Unix98 > PTY support.)
Oh, and I always thought PTYs were moved to free up more minors for our zillions of serial ports... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [EMAIL PROTECTED] In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/