Printer Class Structure - IBM 3270 Manual

Local Mode·
System Mode
Shared Mode
A printer in local mode may be used for local-copy functions regardless of
host attachment or communication protocol. This means that displays
within the cluster may contend for the use of printers but the host may not.
The: printer is not available for direct print operations from the host.
A local-copy operation involves the transfer of data from the display buffer
to the ·printer buffer and the subsequent printing of that data. A local copy
may be initiated by an operator using the Print key on a display station
attached to a 327 4 or by the host when the display is operating in
SNA/SDLC.
A
printer in system mode is entirely under host· (system) control. This is
the default mode each printer assumes when rio matrix has been defined.
The printer cannot be used for operator-initiated local-copy requests; nor is
it available for host-initiated copy operations when using SNA/SDLC.
However, when operating with BSC discipline, the printer may honor a BSC
Copy command when it is in system mode. The BSC Copy c.ommand
1
directed to the to device, specifies the from device as a command parameter
.
~nd
does not.use the printer authorization matrix.
In shared mode, both host-dir.ected printing operations and local-copy
. operations are permitted on the same printer. When in system mode, the
printer is protected from local copies; in local mode, the printer is protected
from host-initiated operations. In shared ~ode, however, the subsystem
does not guarantee this kind of integrity. When using a printer in shared
mode, the user must assume responsibility for the integrity of his printed
data by "installation rules'' and proper programming practices.
In SNA/SDLC, a printer des!gnated as being in shared mode in the printer
. authorization matrix may be use.cl for local .copy under the following
conditions:
• When the printer.is not in session with a.primary logical unit (PLU) in
the host
• When Between Bracket Printer Sharing (sequence number 213) has
been specified in the customizing procedµre and the printer is not in
bracket state with the PL U in the host
Printer Class Structure
··C-2
The printer authorization matrix permits the assignment of a printer to a
class. By the selection of a class containing multiple printers, improved
copy throughput can be obtained. The definition of a class of printers is
made by the customer and may be based on type, character subset, type of
forms mounted, location, and so forth. For example, in a particular
installation class, "72" may have been defined as referring to all printers