1. CS-450-1 Operating Systems
NeXTSTEP
CS Operating Systems
Shaun O’Kelley
Wes Deviers
Jeremy Dunn
William Pope

2. History of NeXTSTEP
In the late 80s NeXT Software Inc. Releases Cube workstation with their own Operating System called NeXTSTEP.
In the mid 90s Apple acquires NeXT continues to develop NeXTSTEP.
NeXTSTEP evolves into Openstep for MACH

3. NeXTSTEP Platforms NeXT Software INC. Cube Motorola 680x0 processors
Intel 386 and 486 processors
R/S6000 RISC processor
Hewlett-Packard PA-RISC workstations
Sun SPARC 4,5, and 10 systems

4. User Interfaces GUI Command Line Primary interface
Booted directly to GUI
Goal of NeXTSTEP was to mesh UNIX with Usability
Command Line
Traditional UNIX-like shell

6. Multi-User Support Multiple local or network accounts
NetInfo System
GUI Desktop profile
telnet, ftp, ssh, etc.
User privacy/security
UNIX-style file/directory permissions (rwx)
Uptime!

7. The Mach Kernel NeXTStep uses the Mach kernel Mach
Called the “Object Oriented” kernel
Microkernel system
Provides basic functionality: Memory management, task management, etc
Other OS responsibilities in daemons
Easily extended with loadable ‘modules’

8. Memory Management Part of the functions provided by Mach
Uses a virtual memory system
Implemented using Demand Paging
The Page swapping algorithm is least recently used

9. Process Management UNIX “process” = Mach “task” + threads
Task serves as abstraction layer for threads
Holds task info (virtual memory tables, access controls, etc)
Threads – An executing process
1+ per task
Synchronized by basic mutex system