[H-GEN] /dev/<consoles>

[Martin Pool]

> Date: Fri, 25 Jul 1997 18:25:53 +1000 (GMT+1000)
> From: Andrae Muys <A.Muys at mailbox.uq.edu.au>

> cui[0-63]
> inportbm
> ippp[0-63]
> logibm (Is this something to do with logitech?)

Logitech bus mouse?

> pty[a-e,p-z][0-f] (I think these are psudeo-terminals, but a. I'm not
> sure, and b. I don't really know what a psudeo-terminal is).

Yes, they are ptys.  ptys are like ttys, except that instead of
communicating with a real serial device or virtual text-mode terminal,
they communicate with another program.  They work kind of like a fifo
in that respect.  

I _think_ the difference is that they _are_ a character device as some
programs may expect that, and they add some of the tty-specific
functionality, like ioctls and so on.

For example, 

> ram[0-7] (I know ram, its in the man page, but what are these
> extra's?)

Ramdisks?  

> nrft[0-3]
> nst[0-7]
> rft[0-3]

Tapes?  On some systems, their are various nodes for the same physical
tape depending on how you want it to behave (st0 is SCSI tape 0, nst0
is the same tape, but in non-rewind mode.)

> rtc

Real-time clock.  Allows you to do pauses and timing at the accuracy
of the hardware clock.

> systty (Is this some sort of syslog tty or something?)
> vcs[a][0-63] (I believe these are virtual consoles, but why 64 of
> them?)

If you enable more gettys in your /etc/inittab, you can have any
number of virtual ttys, up to a compiled-in maximum of 64.
(Control-Meta-Shift-Cokebottle-F4.)  Alternatively, you can take some
out to save vm on a machine you don't use in text mode.

> Oh, and by the way, would someone be willing to explain to ignorant old
> me, what a tty is and what it's used for, ie why are there so @##%!# many
> of them.

A teletype, or something that acts like one.  Since not many of us
have a Teletype (TM) anymore, it generally means 'a terminal' or 'a
serial device' depending on what system you're on.  This can include
Ctrl-Alt-Fn style virtual terminals, dumbterms connected to the serial
ports, or pseudo-ttys connected to xterms, sshds or telnetds.  

There are lots of them because some machines might have many people
logged on at once.  Apparently there is a problem with the linux tty
code that causes problems when more than 256 tty sessions are
connected at once.

> Sorry for the bother, but I don't know a m to rtf?

If that fails, RTFSource.  You might try grepping for 'nrft' or
whatever device you're interested in in /usr/src/linux.  For example,
I think you can find out how to use /dev/rtc in Documentation/rtc.txt.

-- 
Martin Pool <m.pool at pharos.com.au>
Pharos Business Solutions

/dev/random is worth reading about: writing data to it will make your
computer more random.  Really.
----------------------- HUMBUG General List --------------------------------
echo "unsubscribe general" | mail majordomo at humbug.org.au # To Unsubscribe