Hitchhiker's Guide to Openbsd

8.13 - I get Input/output error when trying to use my tty devices
You need to use /dev/cuaXX for connections initiated from the OpenBSD system, the /dev/ttyXX 
devices are intended only for terminal or dial-in usage. While it was possible to use the tty devices in the 
past, the OpenBSD kernel is no longer compatible with this usage. 
From 
cua(4)
: 
For hardware terminal ports, dial-out is supported through matching device nodes called calling units. 
For instance, the terminal called /dev/tty03 would have a matching calling unit called /dev/cua03. These 
two devices are normally differentiated by creating the calling unit device node with a minor number 
128 greater than the dial-in device node. Whereas the dial-in device (the tty) normally requires a 
hardware signal to indicate to the system that it is active, the dial-out device (the cua) does not, and 
hence can communicate unimpeded with a device such as a modem. This means that a process like 
getty
(8)
will wait on a dial-in device until a connection is established. Meanwhile, a dial-out connection can 
be established on the dial-out device (for the very same hardware terminal port) without disturbing 
anything else on the system. The 
getty(8)
process does not even notice that anything is happening on the 
http://www.openbsd.org/faq/faq8.html (13 of 20)9/4/2011 10:02:10 AM

---

8 - General Questions
terminal port. If a connecting call comes in after the dial-out connection has finished, the 
getty(8)
process will deal with it properly, without having noticed the intervening dial-out action. 
8.14 - What web browsers are available for OpenBSD? 
Lynx
, a text-based browser, is in the base system, and has SSL support. Other browsers in the 
ports tree
, 
include (in no particular order):