SCSI Manager 4.3 is part of the ROM in all versions of the Power Macintosh computer. System 7.5, when installed from the upgrade CD-ROM disc, places the extension in your Extensions folder, but it is not required. The absence or presence of the SCSI Manager 4.3 extension has no bearing on the performance of your Power Macintosh computer. The extension normally provides the benefits of the new SCSI Manager to computers that do not have it in their ROM. The SCSI Manager 4.3.1 extension from System 7.5 Update 1.0 contains software fixes needed only on 68040-based Macintosh computers and the PowerPC Upgrade Card. The 68040-based PowerBook computers do NOT need SCSI Manager 4.3.1 extension because PowerBook computers do not support SCSI Manager 4.3. Mac OS 7.5.3 and later have the SCSI Manager 4.3 functionality included in the system software, so the extension is not needed.
