This chapter is a historical prospective of OS. Most of them are just conceptual, but they are important to understand the evolution of OS. I find its hard to organize the content, so the table of content is not very structured.

Historical Prospective

Mainframe: Batch Systems

• One job at a time
• No interaction between users and jobs
• CPU is often idle (I/O speed « CPU speed)
• OS doesn’t need to make any decision

Mainframe: Multi-programming System

• Overlaps the I/O and computation of jobs
• Spooling (Simultaneous Peripheral Operation On-Line)
  • I/O is done with no CPU intervention
  • CPU just needs to be notified when I/O is done
• Memory management, CPU scheduing, I/O system comes in

Mainframe: Time-sharing System (Multi-tasking System)

• interactive system
  • CPU swiches among jobs so frequently that users may interact with programs
• Switch job when
  • finish
  • waiting I/On
  • a short period of time
• Users will feel like the task run at the same time

New features appear to address new problems

• virtual memory
• file system, disk management
• process synchronization, deadlock

Desktop Systems: Personal Computers

• GUI
• I/O devices
• Lack of file and OS protection

Desktop Systems: Parallel Systems

• multiprocessor or tightly coupled system
• More than one CPU
• communicate through shared memory

Parallel systems can be further classified into

• Symmetric multiprocessor system (SMP)
  • Each processor runs the same OS
  • Most popular multiprocessor architecture
  • Require extensive synchronization to protect
• Asymmetric multiprocessor system
  • Each processor is assigned a specific task
  • One master CPU and multiple salve CPUs
  • Mmore common in extremely large systems

Multi-Core Processor

• A CPU with multiple cores on the same die (chip)
• On-chip communication is faster than between-chip communication
• Also use less power than multiple single-core chips

Memory Access Architecture

• Uniform Memory Access (UMA)
  • Most commonly used todday with SMP
  • identical processors
  • Equal access times to memory
• Non-Uniform Memory Access (NUMA)
  • Each CPU has it’s own memory and can also visit other CPU’s memory
  • Often made by physically linking two or more SMPs
  • Memory access across link in slower
  • Example: IBM Blade server

Distributed Systems

• Each processor has its own local memory
• communicate with various communication lines (I/O, network)
• easy to scale
• Pruposes: resource sharing, load sharing, reliability
• Client-Server Distributed Systems
  • easier to manage and control resourses
  • server becomes the bottle neck
  • Example: FTP
• Peer-to-Peer Distributed System
  • decentralized system
  • Example: torrent, internet
• Clustered System
  • share storage and linked via local area network (LAN)

Special-purpose Systems

• Real-Time Operating Systems
• Multimedia Systems
• Handheld Systems

Real-Time Operatinig Systems

• fixed-time constraints, keeping deadlines
• guaranteed response and reaction times
• Soft real-time
  • Missing deadline is acceptable
  • Examples: multimedia streaming
• Hard real-time
  • Missing deadline results in a fundamental failure
  • Secondary storage (disk) limited or absent

Multimedia Systems

• On-demand/live streaming
• Compression

Handheld Systems

• smart phones
• specialized OS