[comp.os.minix] ST kernel with rs232 -- musings on login on tty1

hcj@lzaz.ATT.COM (HC Johnson) (03/17/89)

> Wim ten Have writes:
> to Login on /dev/tty1:
> a dumb terminal on tty1 needs CRMOD and XTABS
> speed on tty1 changes between 19200 , 2400, and my speed of 9600.

The problem of connecting a device to tty1 that is not itself a minix
ansi terminal is deaper than CRMOD and XTABS.  But I agree, there is
NO output processing in the rs232 driver.  A general fix is to
abandon the obsolete sgtty structures in the kernel and use termio.

The extension of /dev/tty1 to a general set of terminals is an interesting
exercise.


I would suspect that the speed changes arrise from the following.
a. 19200 is a speed of 0.  Someone is doing ioctl to 'stdin' that
   only sets the structure, not modify it.  (For example, 
   Login.c does this, thus
b. 2400 is the default speed I use, and so its in ttyinit().  I suggest
   that anyone planning to run at a known different speed, change this
   here.  It will show up if the port is opened and closed in the wrong
   order.  SH does many unnecessary open/close.  The ultimate fix is to
   train MINIX to know about 'final close', a UNIX(r) basic.
   the necessity of adding the setting of speed.).

Howard C. Johnson
ATT Bell Labs
att!lzaz!hcj
hcj@lzaz.att.com

henry@utzoo.uucp (Henry Spencer) (03/19/89)

In article <477@lzaz.ATT.COM> hcj@lzaz.ATT.COM (HC Johnson) writes:
>... A general fix is to
>abandon the obsolete sgtty structures in the kernel and use termio.

Actually, termio is obsolete too -- POSIX compatibility would be better.
(I haven't seen the details of the final POSIX tty stuff, but my
understanding is that the capabilities are approximately those of termio
but the user interface is different.)
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