TOPIC On a computer running Mac OS X Server and MacOS.app, even though MacOS.app is a full virtual Macintosh implementation and gives every appearance of full Mac functionality, there are certain kinds of hardware that do not work, even though they work normally under Mac OS 8. DISCUSSION The Mac OS X Server Release Notes state, "Direct ADB access is not supported. Applications that read directly from ADB devices and expect mouse ADB events will not work." Mac OS X Server is a direct descendant of BSD unix, implemented using the Mach microkernel. As a rule, an operating system is tightly wedded to the hardware on which it runs, and Mac OS X Server is no exception, so it is accurate to say that "Mach owns the hardware". MacOS.app is a complete and robust implementation of a virtual computer (a virtual Macintosh) that runs as an application within the Mach OS. As such, it directs all input/output requests to the Mach kernel or its processes. Because of this, ADB devices, serial devices, SCSI devices, and PCI devices must be addressed from MacOS.app using standard system calls (most of which are mapped very directly to Mach-side APIs). Any program that attempts to access hardware or memory locations directly from the Blue Box may be ignored, but will more likely hang or crash MacOS.app, often in spectacular or profound fashion. This may not always be escaped with the Command-Shift-Q keyboard force-quit for MacOS.app, either, accounting for another situation in which telnet access can be handy. Thus, devices such as ADB copy-protection "dongles", and some ADB devices such as ADB modems, serial switches, and pointing devices may fail to work or cause MacOS.app to hang or crash. PCI boards that are otherwise unrecognized by BSD and Mach may lead to similar situations if Mac OS drivers are installed within the MacOS.app environment. Programs that issue low-level SCSI commands (such as RAID utilities, disk formatters, and maintenance utilities like SCSI Probe or third-party CD ROM drivers) can be expected to cause similar problems within MacOS.app. For more information about telnet and Mac OS X Server, see the following article: Article 60092: " Mac OS X Server: Why and Why Not to Allow Remote Login. " For more information about ADB and other hardware support, see the following article: Article 60124: " Mac OS X Server Release Notes ." |
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| Document Information | |
| Product Area: | Mac OS System Software |
| Category: | Mac OS X Server |
| Sub Category: | General Topics |
| Keywords: | kmosXserver |
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