In the above responses, "type" is one of the following: DASD TAPE
LINE
RDR
PRT PUN GRAF CONS CTCA
CTLR DEV Direct access storage device Magnetic tape
Communication line
Card reader
Line printer
Card punch
Graphics device
Console
Channel-to-channel adapter 3104 or 3705 Communications Controller
Any other device Section 3. CP Commands 49

ATTACH CHANNEL Use the ATTACH CHANNEL command to dedicate all devices on a particular
channel to a specified user. The addresses by which the virtual machine
user refers to these devices must be the same as the real addresses (he
cannot use minidisks). You do not have to attach the devices
individually on the attached channel to the specified virtual machine
user; he may use any or all of the devices. However, whether idle or
not, you cannot attach the devices on the channel to another user. The
virtual machine must have all I/O stopped before executing the command.
The format of the ATTACH CHANNEL command is:
ATTach CHANNEL c
r ,
CHANnel c (TO] luseridl 1* I L .J
is the real address of the channel to be attached to the user.
CHANNEL is a required reserved word.
r , TO luseridl 1* I L .J
is the user identification of the virtual machine that is to
use the dedicated channel. The user must be logged on in
order to get control of the channel. The userid can be
specified as an asterisk (*) to indicate that the channel is
to be attached to the virtual machine of the class Buser
issuing the co.mand. If the optional keyword TO is omitted,
the userid cannot be TO or T.
Note: A DETACH CHANNEL command followed immediately by an ATTACH CHANNEL
command may result in a message stating that the specified channel is in
use. DETACH CHANNEL processing causes I/O to be asynchronously SCheduled for each dedicated device; DETACH CHANNEL processing does not
wait for all I/O to complete prior to returning control to the terminal
operator. A subsequent ATTACH CHANNEL command may fail due to this
timing situation.
CP sends messages to the user's terminal on the virtual machine to which
the channel is attached, and to the operator who issued the command.
CHANNEL c ATTACHED
is the response to the user who receives dedicated access to the
channel. 50 VK/370 Operator's Guide