What are the different types of software?
System software- All programs that help the
computer function properly
Application software- All the programs you
use to perform a task such as writing a letter
or browsing the World Wide Web
OS Tool: Virtual Machine AbstractionApplication
Operating System
Hardware
• Software Engineering Problem:
– Turn hardware/software
what programmers want/need
– Optimize for convenience, utilization, security, reliability,
etc…
• For Any OS area (e.g. file systems, virtual memory,
networking, scheduling):
– What’s the hardware interface? (physical reality)
– What’s the application interface? (nicer abstraction)
Interfaces Provide Important Boundaries
instruction set
software
hardware
• Why do interfaces look the way that they do?
– History, Functionality, Stupidity, Bugs, Management
Machine interface
Human interface
Software engineering/management
• Should responsibilities be pushed across boundaries?
– RISC architectures, Graphical Pipeline Architectures