The original nanokernel, and the tightly integrated Mac 68k emulator, were written by emulation consultant Gary Davidian.[4] Its main purpose is to allow the existing Motorola 68K version of the operating system to run on new hardware. As such, the normal state of the system is to be running 68K code. The operating system does little until activated by an interrupt, which is quickly mapped to its 68K equivalent within the virtual machine.
Other tasks may include switching back to PowerPC mode, if necessary, upon completion of the interrupt handler, and mapping the Macintosh virtual memory system to the PowerPC hardware. However, as the software is little documented, these might instead be handled by the emulator running in user mode.
This nanokernel is stored on the Mac OS ROM chip integrated into Old World ROM computers, or inside the Mac OS ROM file on disk on the New World ROM computers, rather than being installed in the familiar sense.
Interim developmentedit
Progress after 1994 demanded additional functionality. A forward-looking architecture was introduced for PCI card drivers in anticipation of the Copland microkernel called NuKernel, which supports memory protection. The Open Transport networking architecture introduced standardized PowerPC synchronization primitives. The DayStar Digital Genesis MP Macintosh clone requires kernel extensions to support multiprocessing. This evolution would later affect the overhaul to the nanokernel in Mac OS 8.6.
Mac OS 8.6 and lateredit
Mac OS 8.6's nanokernel was rewritten by René A. Vega to add Multiprocessing Services 2.0 support. PowerMacInfo, distributed in the Multiprocessing SDK, is an application that displays statistics about the nanokernel's operation.[5]
Referencesedit
^Inside Macintosh: PowerPC System Software. Apple Technical Library. Reading, Mass.: Addison-Wesley Pub. Co. 1994. ISBN978-0-201-40727-3. OCLC 29636881.
^. Apple Technical Library. Apple Computer, Inc. July 3, 1996. Archived from the original on May 18, 2008. Retrieved April 4, 2013.
^. Apple Computer, Inc. March 27, 1997. Archived from the original on June 23, 2004. Retrieved April 4, 2013.
^"The Road to Power Macintosh". Macworld. Vol. 11. May 1994.
^René A. Vega (October 25, 2001). "PowerMacInfo info". Newsgroup: comp.sys.mac.programmer.help. Retrieved May 12, 2016.
External linksedit
René A. Vega's explanation of basic Mac OS architecture
supervisor mode
Question from a non-programmer
January 01, 1970
nanokernel, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, february, 2012,. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Mac OS nanokernel news newspapers books scholar JSTOR February 2012 Learn how and when to remove this message The Mac OS nanokernel is an operating system kernel serving as the basis of most PowerPC based system software versions 7 through 9 of the classic Mac OS predating Mac OS X The initial revision of this software is a single tasking system which delegates most tasks to an emulator running the Motorola 68000 series 68K version of the operating system The second major revision supports multitasking multiprocessing and message passing and would be more properly called a microkernel Unlike the 68K derived Mac OS kernel running within it the PowerPC kernel exists in a protected memory space and executes device drivers in user mode The nanokernel is very different from the Copland OS microkernel although they were created in succession with similar goals 1 2 3 Contents 1 System 7 1 2 Mac OS 8 5 1 2 Interim development 3 Mac OS 8 6 and later 4 References 5 External linksSystem 7 1 2 Mac OS 8 5 1 editThe original nanokernel and the tightly integrated Mac 68k emulator were written by emulation consultant Gary Davidian 4 Its main purpose is to allow the existing Motorola 68K version of the operating system to run on new hardware As such the normal state of the system is to be running 68K code The operating system does little until activated by an interrupt which is quickly mapped to its 68K equivalent within the virtual machine Other tasks may include switching back to PowerPC mode if necessary upon completion of the interrupt handler and mapping the Macintosh virtual memory system to the PowerPC hardware However as the software is little documented these might instead be handled by the emulator running in user mode This nanokernel is stored on the Mac OS ROM chip integrated into Old World ROM computers or inside the Mac OS ROM file on disk on the New World ROM computers rather than being installed in the familiar sense Interim development editProgress after 1994 demanded additional functionality A forward looking architecture was introduced for PCI card drivers in anticipation of the Copland microkernel called NuKernel which supports memory protection The Open Transport networking architecture introduced standardized PowerPC synchronization primitives The DayStar Digital Genesis MP Macintosh clone requires kernel extensions to support multiprocessing This evolution would later affect the overhaul to the nanokernel in Mac OS 8 6 Mac OS 8 6 and later editMac OS 8 6 s nanokernel was rewritten by Rene A Vega to add Multiprocessing Services 2 0 support PowerMacInfo distributed in the Multiprocessing SDK is an application that displays statistics about the nanokernel s operation 5 References edit Inside Macintosh PowerPC System Software Apple Technical Library Reading Mass Addison Wesley Pub Co 1994 ISBN 978 0 201 40727 3 OCLC 29636881 Inside Macintosh PowerPC System Software Apple Technical Library Apple Computer Inc July 3 1996 Archived from the original on May 18 2008 Retrieved April 4 2013 Technical Note TN1084 Running CFM 68K Code at Interrupt Time Is Your Code at Risk Apple Computer Inc March 27 1997 Archived from the original on June 23 2004 Retrieved April 4 2013 The Road to Power Macintosh Macworld Vol 11 May 1994 Rene A Vega October 25 2001 PowerMacInfo info Newsgroup comp sys mac programmer help Retrieved May 12 2016 External links editRene A Vega s explanation of basic Mac OS architecture supervisor mode Question from a non programmer Retrieved from https en wikipedia org w index php title Mac OS nanokernel amp oldid 1146997116, wikipedia, wiki, book, books, library,
