SUMMARY- What is :TTY Question.

From: joe crawford (
Date: Fri Sep 15 2000 - 11:29:39 CDT

Surprising? So many said they were waiting for my

Thanks to Max Trummer, Jeff lightner, Arthur Darren
Dunham and reggie stuart.
Here are the responses:

Arthur Darren Dunham:
TTY used to mean a real attached terminal. That's
what a /dev/tty
should be, a phsyical terminal. (eg. /dev/term/a)
PTY is a "pseudo" terminal. It's a network connection
that looks to
system like a terminal. (eg. /dev/pts/5)

The 'tty' command will give you which terminal you are

In Solaris the 'console' is a special terminal that is
handled by the
OBP hardware. It can be either an attached keyboard
and monitor, or it
can be a serial port.

Since it's handled by the hardware before the OS even
boots, the OS
doesn't really distinguish between the two. They're
both simply

Jeff lightner:

You basically have three kinds of devices for user

console - This is the main terminal on the system
where system
messages appear usually allows lower level control of
the system than
other devices. This in the early days was just a
specialized device
similar to ttys (used "dumb" terminals) but over time
many systems
have allowed for graphical monitors such as those used
on PCs. You
usually want to make sure physical access to your
console is
restricted because of its power. (For Sun and HP
machines you can go
into special firmware/maintenance modes on the
consoles even if you
don't know the root password.)

tty - This is a directly attached serial connection.
These could be a
directly attached "dumb" terminal, a modem or even a
PC that had
terminal emulation. Also printers that aren't
networked are usally
attached serially via ttys.

ptys - These are pseudo-ttys. They are used in UNIX
to represent
network connections. A major difference between
these and real ttys
is that each time you login or logout over the network
your apt to get
a different pty but on a hardwired device you'd always
get the same

Max Trummer:

'tty' of course, stands for teletype. back in the old
days, you usually
connected to a unix system via a terminal ( or a real
teletype ) and a
serial line. every tty had a device file in the /dev
directory ( wouls
also be /devices, now ).

this gets into things like stty, tset, ioctl, etc,
things you can use
to control the characteristics of a tty. also the TERM
env variable and
the termcap/terminfo files.

many servers don't have graphic cards nor keyboards
attached. when suns
boot up, if there's no keyboard/screen, the default
port to use for the
console is /dev/ttya ( sometimes /dev/ttyb ). you can
change this
default behaviour from the open boot prom, either via
the ok> prompt or
by using the eeprom command.

Thnaks to all these people once again...

One more question to add...I have been given the
responsibility of clearcase/clearDDTS administration
too. Does anyone know a good book for clearcase admin
or good web site that could be of use. TIA.


Do You Yahoo!?
Yahoo! Mail - Free email you can access from anywhere!

U BEFORE POSTING please READ the FAQ located at
. and the list POLICY statement located at
A To submit questions/summaries to this list send your email message to:
A To unsubscribe from this list please send an email message to:
E and in the BODY type:
R unsubscribe sun-managers
S Or
. unsubscribe sun-managers original@subscription.address
L To view an archive of this list please visit:

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:14:17 CDT