Apple Desktop Computer manual Contents

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Contents

	Figures and Tables			7
Preface	About This Developer Note						9

	Contents of This Note			9
	Supplemental Reference Documents						10
	PowerPC G3 Microprocessor					10
	Mac OS	10
	ATA Devices		10
	USB Devices		11
	Open Firmware			11
Chapter 1	Introduction		13

	Features	14
	Case and External Features				15
	Compatibility Issues			18
	System Software			18
	Main RAM Expansion Modules						19
	Video RAM Expansion Modules						19
	USB Ports and Devices				19
Chapter 2	Architecture		21

	Processor module			23
	G3 Microprocessor			23
	Backside Cache			23
	Memory Controller and PCI Bridge						24
	Main Logic Board			24
	I/O Controller IC			24
	USB Controller			25
	Video Display Subsystem				25
	Built-in Modem			25

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Contents Apple iMac Computer Page Contents RAM Expansion Devices and PortsRtas SoftwareRtas NV-RAM Appendix Abbreviations IndexFigures and Tables Page About This Developer Note Contents of This NoteATA Devices PowerPC G3 MicroprocessorSupplemental Reference Documents Mac OSOpen Firmware USB DevicesE F a C E Introduction Features Shows a front view of the computer Case and External FeaturesFront view 2Side view showing I/O bay System Software Compatibility IssuesMain RAM Expansion Modules Video RAM Expansion ModulesUSB Ports and Devices Page Architecture Architecture Processor module G3 MicroprocessorBackside Cache Main Logic Board Memory Controller and PCI BridgeController IC USB Controller Video Display SubsystemBuilt-in Modem Infrared Link Module Devices and Ports USB Ports USB ConnectorsGND Transfer Types SupportedADB Compatibility USB Compatibility IssuesUSB Controller Serial Port CompatibilityMacintosh-To-Macintosh Connections USB Storage DevicesKeyboard Layout KeyboardKeyboard and USB MouseVideo Display Hard Disk DriveSound System Infrared Communication LinkExternal Sound Input Sound InputsSound Outputs Built-in MicrophoneSound Speciﬁcations External Sound OutputHeadphone Jacks Total harmonic distortion Internal Modem Ethernet PortPage RAM Expansion Removing the Logic Board Assembly Expansion SlotsPlacing the Computer Face Down Unfastening the Cables Removing the bottom coverRAM Expansion Removing the Retaining Screws 3Logic board assembly handle and retaining screwsRemoving the EMI Shield Removing the Logic Board AssemblyLocations of the Expansion Slots 6Locations of the RAM expansion slots Main RAM ExpansionElectrical Design of RAM SO-DIMMs Mechanical Design of RAM SO-DIMMsSdram Devices Conﬁguration of RAM SO-DIMMs Address Multiplexing RAM SO-DIMM Electrical LimitsVideo RAM Expansion Page Software Why Make This Change? What Has Changed Features of the New Approach Data Structures and Files PerformanceRAM Footprint User ExperienceBoot ROM Contents Rtas Mac OS ndrv DriversToolbox Image File Contents NewWorld Boot Process Trampoline CodeToolBox ROM Image Interrupt Handling What Is DifferentRAM Footprint Outmoded ResourcesStartup Disk Control Panel NanoKernelOpen Firmware and the Device Tree Interrupt LayoutMachine Identiﬁcation Software Abbreviations Chrp NMI Page Index Nvram X, Y, Z Allen Watson