Browse Prior Art Database

Generic Family Type

IP.com Disclosure Number: IPCOM000123531D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 99K

Publishing Venue

IBM

Related People

Albert, M: AUTHOR [+2]

Abstract

When a new I/O device is introduced, it usually has a new device number, which must be added to already-shipped device-support code so it can recognize the new device type. With Generic Family Type, the device reports the Generic Family of which it is a part. The device support code is enhanced to understand Generic Family Type, so that devices in an already supported family can be used without PTFs to device support code.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Generic Family Type

      When a new I/O device is introduced, it usually has a new
device number, which must be added to already-shipped device-support
code so it can recognize the new device type. With Generic Family
Type, the device reports the Generic Family of which it is a part.
The device support code is enhanced to understand Generic Family
Type, so that devices in an already supported family can be used
without PTFs to device support code.

      MVS/SP 4.2.0 supports dynamic I/O, which allows the I/O
configuration of a computer system to be defined and changed
dynamically, without having to statically define the I/O
configuration, generate the configuration, generate the new MVS
control program, IML the central processor, and IPL the control
program.

      Device owners (e.g., VTAM) are responsible for providing
software support, as a component of MVS, for the devices which are
attached to the system.  For example, VTAM supports communications
controllers.  When new devices (with new device type numbers) become
available, software support must be changed.  This results in IBM
generating a PTF, the customer installing it, and the customer
re-IPLing his system.

      The device support provided by the device owners must include
tests to verify that the newly added I/O device is one that is
supported.  This must be done before the device is allowed to be used
to ensure that incorrect commands -- which could cause security or
integrity exposures, overwrite valid data, or even cause physical
harm to the device -- are not sent to the device.

      The device is able to identify itself, in response to the Read
Configuration Data (RCD) Channel Command Word (CCW).  The device-
support code issues this command to the device, when the device has
been physically attached to the system.  The device responds with its
device type, which the device-support code uses to verify that it is
one of the devices understood by that subsystem.

      When a new model of a device is announced, it is usually given
a new device type (generally a number, e.g., a 3745 Communications
Controller).  Thus, the subsystem device-support code must be updated
to understand this new device type.  In order to update the device-
support code currently running in customers' systems, a PTF is
shipped to the customer, who has to install it on his system.  The
installation of the PTF requires the entire system to be stopped, and
then restarted, a process known as re-IPL.  This process is very
disruptive to production systems, and...