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Browse Prior Art Database

Stand-Alone and Multi-Unit Devices Share Common Driver

IP.com Disclosure Number: IPCOM000118105D
Original Publication Date: 1996-Sep-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 82K

Publishing Venue

IBM

Related People

Oman, PS: AUTHOR

Abstract

Disclosed is an object-oriented means by which a multi-unit peripheral device that partially emulates multiple stand-alone devices can share a common device driver with true stand-alone device(s) of the emulated type. It handles host commands that are sent to a single unit that affects other units in the device as well as device messages that are sent to one controlling host, but need to be responded to by each of the hosts controlling units within the device.

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

Stand-Alone and Multi-Unit Devices Share Common Driver

      Disclosed is an object-oriented means by which a multi-unit
peripheral device that partially emulates multiple stand-alone
devices can share a common device driver with true stand-alone
device(s) of the  emulated type.  It handles host commands that are
sent to a single unit  that affects other units in the device as well
as device messages that  are sent to one controlling host, but need
to be responded to by each of the hosts controlling units within the
device.

      For example, the issuance of a Prevent Media Removal command
to a single unit of a Common Driver (CD) changer affects all of the
units in the changer when media is maintained in a magazine that the
units share.  Also, when a device becomes aware of a condition that
needs to be reported to the controlling host, such as a power-on
reset (which may occur if a device is "hot-swapped") the device may
send only one message (which will be associated with only one
attached unit) even though all units are affected and each of their
controlling hosts need to be notified of the condition.

      This solution uses a software subscription list (one for each
attached peripheral device whether stand alone or not), into which an
object that is uniquely associated with a device unit (or the device
itself in the stand alone case) must enroll.  The subscription lists
are maintained in a static map object in which they are mapped
(indexed) by a unique device identifier.  This allows simultaneous
attachment of more than one multi-unit peripheral device (Fig. 1).

     ...