CP6100 I/O Process Programming Manual

Introduction
Implications for CP6100
In summary, when you develop an interface with CP6100 or convert
an existing interface to use CP6100, applications that use the
interface gain several important benefits:
| • Availability. Because there are up to four paths to any line
| controlled by CP6100, not even a controller failure can make a
| line unavailable.
| NOTE
|
| Although in the single-port controller configuration
| there are only two paths to any line, no single com-
| ponent failure affects more than one line; thus, a
| controller failure cannot make a line unavailable.
• Performance. Because protocols don't run in the NonStop
System processors--rather, they run in processors within the
6100 subsystem--the system overhead for controlling each line
is reduced. Also, because the I/O process and protocol are
independent modules, you don't need separate I/O processes to
control lines with different protocols; the same process can
take requests for different kinds of lines. Both these
factors can improve the performance of your applications and
allow smaller systems to handle more lines than they
previously could.
• Flexibility. Because protocol modules are downloaded into the
6100 subsystem, creating new protocols doesn't mean producing
and installing new hardware. Nor does it require updating of
CP6100 software. Likewise, changing a configuration (to put
different lines in different places in the system, or to
change the protocol for a given line) requires no hardware
modification. You don't even need to unplug anything.
October 1985
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