Infinity Sound Driver

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Infinity Sound Driver
Released 1989-??-??
Programmers Infinity
Language 8086 Assembly
Formats INF, BIN

The Infinity Sound Driver is a sound driver created by the Infinity company for their games released on the X68000 and PC-9801 Japanese computer lines. Although the first releases of the driver are dated 1989, some of the copyrights use a date of 1986. However, this is probably the date the Infinity began as a company, not when they wrote the driver. The last updated driver carries a date of 1992. For the X68000, the driver program is named OPMDRV.X, and for the PC-9801, it is named OPNDRV.COM. Music files are stored with a .BIN extension, however, to more easily identify their format, the files should be given an .INF extension when uploaded to the VGMPF.

While details about the driver are unknown, it was probably programmed in 8086 assembly, possibly by Kazuo Sawa who is credited as the musician for nearly every game that uses this driver, and wrote several audio drivers in his career.

Release History

There are four verified versions of the driver, 1.00, 1.10, 2.00 and 2.10 which can be found at the beginning and end of the OPMDRV.X and OPNDRV.COM files. In the OPNDRV builds, the version number at the end of the file always matches the number at the top, but, at the end of the OPMDRV.X files, a version number of 0.80 is always listed. This may have been a beta version number that was created during testing and never updated in subsequent OPMDRV builds.

The version numbers are not entirely sequential, but rather all version 1 releases are for the X68000 and all version 2 releases are for the PC-9801. However, increases in the decimal value do indicate a later version.

Those versions labeled "revision" use the same version number but include later copyright dates. They are definitely new builds of the program, but it is unknown if the driver changed at all.

Released Version
1989-??-?? 0.80 (possible beta version)
1989-??-?? 1.00
1989-??-?? 1.10
1989-??-?? 2.00
1990-??-?? 2.10
1992-??-?? 1.10 Revision
1992-??-?? 2.10 Revision


The Infinity Sound Driver sent audio instructions either to the Yamaha YM2151 OPM chip for X68000 programs or to the Yamaha YM2203 OPN chip for PC-9801 programs.


Released Title Sample Version
1989-11-21 Ultima III: Exodus (PC98)
Version 2.00
1990-03-16 Populous (PC98) Version 2.10
1990-03-23 Populous (X68)
Version 1.10
1990-07-21 Ultima V: Warriors of Destiny (PC98) Version 2.00
1990-07-21 Ultima V: Warriors of Destiny (X68) Version 1.00
1991-10-25 Powermonger (PC98) Version 2.10
1991-10-25 Powermonger (X68) Version 1.10
1992-08-28 Populous II: Trials of the Olympian Gods (X68) Version 1.10 Revision
1993-02-05 Populous II: Trials of the Olympian Gods (PC98) Version 2.10 Revision

Need to check the following games:

  • Ultima III: Exodus (PC88)
  • Ultima III: Exodus (X1)
  • Ultima V: Warriors of Destiny (PC88)