1. Seminar Origins of Operating Systems
The Microkernel Mach
in NeXTSTEP
Gregor Schmidt
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 1 1

2. The NeXTSTEP operating system The Mach Microkernel The next steps
Overview
Introduction
The road to NeXTSTEP
The NeXT computers
The NeXTSTEP operating system
The Mach Microkernel
Interprocess Communication by example
The next steps
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 2 2

3. The NeXTSTEP operating system The Mach Microkernel The next steps
Overview
Introduction
The NeXTSTEP operating system
The Mach Microkernel
The next steps
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 3 3

4. 1986 - NeXT computers, Inc. was founded by Steve Jobs and
The Road to NeXTStep
NeXT computers, Inc. was founded by Steve Jobs and
colleagues from Apple
Rich Page
George Crow
Bud Tribble
Dan‘L Lewin
Susan Barnes
and
Randy Heffner
Gary H. Moore
The first computer was presented
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 4 4

5. $ 4.995,- 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)
105 MB SCSI HDD
Floppy Disc Drive
10Base-T and 10Base-2 Ethernet
Monochrome Display
All later versions of NeXTSTEP operating systems run on these machines
$ 4.995,-
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 5 5

6. The NeXTSTEP operating system The Mach Microkernel The next steps
Overview
Introduction
The NeXTSTEP operating system
The Mach Microkernel
The next steps
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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
BSD re-factoring
BSD-Reno for Mach
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 7 7

8. The NeXTSTEP Operating System Demo - By Steve Jobs
Product Demonstration of NeXTSTEP Release 3.0
1:00 Start
6:30 Word Perfect
24:00 Interface Builder
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 8 8

9. The NeXTSTEP operating system The Mach Microkernel The next steps
Overview
Introduction
The NeXTSTEP operating system
The Mach Microkernel
The next steps
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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 2.5
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 10 10

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
lots of communication overhead
lots of synchronization
small interface
little trusted computing base
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 11 11

12. The Mach Microkernel Main Features
Preemptive Multitasking
Multithreading, Multiprocessing
Memory protection, virtual memory
Interprocess communication via mach messages
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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
in Mac OS X: Bootstrap Server
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 14 14

15. The Mach Microkernel Message Sending the Easy Way
Mach Interface Generator
Corba-like Stub-and-Skeleton-Generator
Message encoding and decoding for free
Little RPC-specific code
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 16 16

17. The NeXTSTEP operating system The Mach Microkernel The next steps
Overview
Introduction
The NeXTSTEP operating system
The Mach Microkernel
The next steps
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 17 17

18. 1995 - reorganization of NeXT towards software
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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 19 19

20. 1996 - take over by Apple, Inc. - 400 Millions US$
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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 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: < berlin.de/~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
Gregor Schmidt Origins of Operating Systems - The Microkernel Mach
Betriebssysteme und Middleware / Prof. Andreas Polze
Hasso-Plattner-Institut 21 21