Browse Prior Art Database

Generic OS/2 Support for CD-ROM Devices

IP.com Disclosure Number: IPCOM000113729D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 90K

Publishing Venue

IBM

Related People

Efruss, RM: AUTHOR

Abstract

Disclosed is the implementation of a modular CD-ROM device driver design for the IBM OS/2* Operating System. In order to provide support for a wide variety of CD-ROM devices, which may, or may not, be attached in accordance with Small Computer System Interface (SCSI) standards, a modular approach has been implemented, allowing the integration of device-specific modules at appropriate levels to mask the underlying incompatibilities of various CD-ROM devices.

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This is the abbreviated version, containing approximately 52% of the total text.

Generic OS/2 Support for CD-ROM Devices

      Disclosed is the implementation of a modular CD-ROM device
driver design for the IBM OS/2* Operating System.  In order to
provide support for a wide variety of CD-ROM devices, which may, or
may not, be attached in accordance with Small Computer System
Interface (SCSI) standards, a modular approach has been implemented,
allowing the integration of device-specific modules at appropriate
levels to mask the underlying incompatibilities of various CD-ROM
devices.

      The concept of this design is shown in the Figure.  The CD-ROM
Device Manager 10 is a generic SCSI-2 CD-ROM device manager,
providing a uniform interface between client programs and Adapter
Device Drivers.  The Device Manager 10 provides generic data and
audio command support for CD-ROM devices and for lower level software
modules complying with the ANSI SCSI-2 Standard, level 10g of
September, 1991.  Client programs of the CD-ROM Device Manager
include the CD-ROM Installable File system, the OS/2 kernel and OS/2
application programs.  The interface between Device Manager 10 and
various device drivers below it is defined by the IBM OS/2* OEM DASD
and SCSI Device Driver Specification.  In accordance with this
specification, the Device Manager converts requests from client
programs into one or more SCSI-2 Command Descriptor Blocks, sending
these SCSI-2 commands to the specified Adapter Device Driver.  The

Device Manager 10 is loaded by means of a statement in the CONFIG.SYS
file, allowing easy replacement of a module.

      A SCSI CD-ROM Device 12, which supports vendor-unique commands
not supported in the SCSI-2 standard, requires a SCSI-2 Emulation
Filter 14 to map the SCSI-2 commands received from Device Manager 10
to the vendor-specific commands supported by the device.  Such a
device is attached through a SCSI bus adapter 15.  For example, such
support is needed to enable audio support on those CD-ROM drives
which adhere to the SCSI-1 standard, since the SCSI-1 standard does
not define a standard command set for aud...