Browse Prior Art Database

Spare Ports for Concurrent Maintenance

IP.com Disclosure Number: IPCOM000103437D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 62K

Publishing Venue

IBM

Related People

Coons, JK: AUTHOR [+4]

Abstract

Disclosed is a means of doing maintenance concurrent with normal operation using spare ports and moving the communicating cable to the spare.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

Spare Ports for Concurrent Maintenance

      Disclosed is a means of doing maintenance concurrent with
normal operation using spare ports and moving the communicating cable
to the spare.

      Spare port availability is assured by preventing these ports
from being used in normal operation.  This is done by preventing the
addressing of these ports in normal operation.  One means is to
provide a higher order address bit that is not available to
programming.  The other means is by use of a translate table that
moves spare ports that are normally out of a program's address range,
into the address range and as a substitute for a failing port.

      The embodiment of the ports is in a box containing a large
number of working ports that communicate with other ports of other
devices (e.g., channel) via fiber optic cables.  Spare ports are not
addressable by normal programming.  The spare ports have an address
that is beyond the range of the programming function.  One way is to
limit addressing to a specific range of addresses.  This can be done
with an address range check in microcode or hardware. Another way of
checking on the range is by having a translate table.  This table
assigns a physical address for a particular logic address.  The
logical address is found in a table and the output of this table is
another address which provides the physical address of the port.  The
spare ports are not found in the table.  They are only placed in the
table when sub...