The Microkernel Mach

Transkript

1 Seminar Origins of Operating Systems The Microkernel Mach in NeXTSTEP

2 Overview Introduction The road to NeXTSTEP The NeXT computers The NeXTSTEP operating system The Mach Microkernel Interprocess Communication by example The next steps 2 2

3 Overview Introduction The NeXTSTEP operating system The Mach Microkernel The next steps 3 3

4 The Road to NeXTStep NeXT computers, Inc. was founded by Steve Jobs and colleagues from Apple and - Rich Page - George Crow - Bud Tribble - Dan L Lewin - Susan Barnes - Randy Heffner - Gary H. Moore The first computer was presented 4 4

5 The NeXT computers based on Motorola 680x0 2 basic models NeXTcube (1989) NeXTstation (1990) - 25 MHz resp. 33 MHz - 8 MB RAM (up to 32 MB) MB SCSI HDD - Floppy Disc Drive - 10Base-T and 10Base-2 Ethernet - Monochrome Display $ 4.995,- All later versions of NeXTSTEP operating systems run on these machines 5 5

6 Overview Introduction The NeXTSTEP operating system The Mach Microkernel The next steps 6 6

7 The NeXTStep Operating System Main Features Mach Kernel BSD4.3 user space server NeXTSTEP user interface Display Postscript Object-oriented application framework Objective C as standard programming language Extraordinary OO-development tools High integration of all native applications 7 7

8 The NeXTSTEP Operating System Demo - By Steve Jobs Product Demonstration of NeXTSTEP Release

9 Overview Introduction The NeXTSTEP operating system The Mach Microkernel The next steps 9 9

10 The Mach Microkernel History developed at Carnegie-Mellon university Microkernel Deployed in several systems NeXTSTEP / OPENSTEP - Rhapsody - Mac OS X GNU/Hurd MkLinux Tru64 (OSF/1) NeXTSTEP uses Mach

11 The Mach Microkernel Microkernel Little features - great reliability Only the main features run in privileged mode Process management - Scheduling Synchronization and communication Device drivers and all other services run as user services small interface little trusted computing base lots of communication overhead lots of synchronization 11 11

12 The Mach Microkernel Main Features Preemptive Multitasking Multithreading, Multiprocessing Memory protection, virtual memory Interprocess communication via mach messages 12 12

13 The Mach Microkernel Interprocess Communication Transparent network support Typed messages including type conversion between different languages Integrated with virtual memory local messages are not copied but mapped into receiver s address space Remote messages are send lazily Port Rights Management Ownership Receive Send Port names - unique Integer 13 13

14 The Mach Microkernel How to find Ports in NeXTStep Environment Manager for local use only Network Message Server enables network-wide communication Service Server netname_look_up() 2 packets_client 3 4 netmsgserver netname_check_in() send_packet() 1 packets_server in Mac OS X: Bootstrap Server 14 14

15 The Mach Microkernel Message Sending the Easy Way Mach Interface Generator Corba-like Stub-and-Skeleton-Generator packets.defs Message encoding and decoding for free Little RPC-specific code generate include mig packets.h generate include packets_client.c packetsuser.c packetsserver.c packets_server_main.c link link packets_client packets_server 15 15

16 The Mach Microkernel Interprocess Communication by Example Calculator example Server providing calculation facilities Client using command line interface to receive tasks and queries server for the answer 16 16

17 Overview Introduction The NeXTSTEP operating system The Mach Microkernel The next steps 17 17

18 The next steps reorganization of NeXT towards software NeXT computers, Inc. - NeXT software, Inc. NeXTSTEP - OPENSTEP support for different platforms all NeXT computers Intel based computers PA-RISC Workstations Sun SPARC (IBM PPC) in labs WebObjects - first application server 18 18

19 The next steps OpenStep and OPENSTEP OpenStep is an object oriented API Designed by NeXT and Sun OPENSTEP is an implementation Other for Windows NT Solaris Linux - GNUStep Main components Display PostScript Objective-C Runtime and Compilers Majority of NeXTSTEP's Objective-C libraries 19 19

20 The next steps take over by Apple, Inc Millions US$ OPENSTEP becomes Mac OS X with a new User Interface - Aqua but the same underlying system components Mach enhanced to XNU (hybrid kernel) within Darwin 20 20

21 References BOYKIN, Joseph; KIRSCHEN, David; LANGERMAN, Alan; LoVERSO; Susan: Programming under Mach. Addison-Wesley UNIX and Open System Series, ISBN , Addison-Wesley 1993 GARFINKEL, Simon L.; MAHONEY, Michael K.: NeXTSTEP PROGRAMMING STEP ONE: Object-Oriented Applications. TELOS. The Electronic Library of Science ISBN , Springer-Verlag 1993 POLZE, Andreas: Vereiltes Rechnen unter Mach. unix/mail 2/1995, Carl Hanser Verlag München. Verfügbar im Internet: < ~apolze/papers/um2-95.ps>. - online im Internet SLABIHOUD, Stephan: NeXT Computer, Inc., , Verfügbar im Internet: < Stand: Juni online im Internet Special References: en.wikipedia.org - for lots of information around NeXTStep and Mach lists.apple.com - for good code example and special information 21 21