Planning Considerations for Other Virtual Machines r IFunction I AUTHORIZE UNAUTHORIZE SEND SEND/RECV SENDX RECEIVE CANCEL REPLY QUIESCE RESUME , IDENTIFY I I I REJECT I I i
ICode
t I Control
Control
Data
Data
Data I ,Data I I I Control I I I IData , I I I Control I I I I Control , I 1
,Control , I , Control , , Comments , I 1Initialize VMCF for a given virtual machine. IOnce AUTHORIZE is executed, the virtual
Imachine can execute other VMcr functions
Ireceive messages or requests from other ,users. and I I ,Terminates VMCF activity. I I , , , I 1Directs a message or block of data to another I virtual machine. Provides the capability to send and receive
data on a single transaction.
Directs data to another virtual machine on a
faster but more restrictive protocol than the SEND function.
Allows you to accept selective messages or
data sent via a SEND or SEND/RECV function.
Cancels a message or data transfer directed
to another user but not yet accepted by that
user.
Allows you to direct data back to the
originator of a SEND/RECV function,
simulating full duplex communication.
Temporarily rejects further SEND, SENDX, SEND/RECV, or IDENTIFY requests from other
users.
Resets the status set by the QUIESCE function
and allows execution of subsequent requests
from other users.
Notifies another user that your virtual
machine is available for VMcr communication.
Allows you to reject specific SEND or SEND/RECV requests pending for your virtual
machine. I ItData indicates a data transfer function. I Control indicates a VMCF control function. L- Figure 8. Virtual Machine Communication Facility (VMCF) Functions 50 IBM VM/370 Planning and System Generation Guide

3270s
Planning Considerations for 3270s attachments can be considered either local or remote. Local
attachments are all devices that do not require telecommunication lines.
However, many devices that are supported for local attachment are also
supported for remote attachment. Remote attachments are devices that
are attached to binary synchronous lines. Such configurations usually
include: • a designated channel • a designated communication controller or transmission control unit • the device or control unit (for terminal attachment and/or RJE
systems) .
Remote Attachments
Both remote cluster and standalone configurations are supported. This
support includes: • Nonswitched point-to-point binary synchronous transmission. • Switched binary synchronous transmission for 3275 terminals equipped
with the Dial feature only. • Cluster configurations of up to 32 display stations and/or printers. • The local 3270 copy function. • EBCDIC (Extended Binary Coded Decimal Interchange Code) transmission
code only. • 3270s supported as virtual machine operator consoles. • CP commands allowing the operator to activate and deactivate the
teleprocessing lines, display stations and printers. • CMS Editor support. • The recording of MDR (Miscellaneous Data Recorder) records and OBR (Outboard Recording) records on the VM/370 error recording cylinder.
The MDR records are for the station and the OBR records are for the
line. The CPEREP program edits and prints these records.
The 3270 copy support allows the user to assign a screen copy
function to a 3270 program function key. pressing that key transfers
the current display image, in its entirety, to an available printer
attached to the same control unit. If the printer is busy or otherwise
not available when the copy function is invoked, the virtual machine
user receives a NOT ACCEPTED message in the screen's status area.
The following restrictions apply to V"/370's support of remote 3270s: • 3270 terminals cannot be used as primary or alternate V"/370 system
consoles.
Part 1. Planning for System Generation 51