Operating Systems Sameer Mahajan Overview Process management Interrupts

Overview • Process management • Interrupts • Memory management • File system • Device

History • 1940’s First Generation – no OS • 1950’s Second Generation – single

Types • • • Realtime Single user vs. Multi user Multi-tasking vs. Single-tasking Distributed

Examples • UNIX – 1% • Mac OS (Lion, Snow Leaopard, Leopard, X Server)

Components • • • Kernel Program Execution (Process) Interrupts Modes Memory Management – virtual

File system • • Boot block Super block Inode Table Data blocks User File

Process • • • Unit of execution User and kernel mode Context: stack, registers,

Scheduling Algorithms • • FCFS Scheduling Round Robin Scheduling Priority Scheduling Multilevel Queue Scheduling

IO subsystem • • Open, close, read, write Character device – ioctl Block device

Inter process communication • • • Messages (msg*) Shared memory (shm*) Semaphores (sem*) Sockets

Windows 8 features Metro User Interface Internet Explorer 10 Apps and App Store New

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Operating Systems Sameer Mahajan

Overview • Process management • Interrupts • Memory management • File system • Device drivers • Networking (TCP/IP, UDP) • Security (Process/Memory protection) • I/O

History • 1940’s First Generation – no OS • 1950’s Second Generation – single stream batch • 1960’s Third Generation – multiprogramming batch • Fourth Generation – microprocessor

Types • • • Realtime Single user vs. Multi user Multi-tasking vs. Single-tasking Distributed Embedded

Examples • UNIX – 1% • Mac OS (Lion, Snow Leaopard, Leopard, X Server) – 6% • Google chrome • Amiga. OS • MS Windows (8, 7, Vista, XP, w 2 k 8, w 2 k 3) – 90% • Mobile Devices – i. OS, Android, Windows Phone 7, Symbian

Components • • • Kernel Program Execution (Process) Interrupts Modes Memory Management – virtual vs physical Multitasking – scheduling File systems – VFS Device drivers Networking Security User interface (GUI, CLI)

Kernel

File system • • Boot block Super block Inode Table Data blocks User File Descriptor (FD) table File Table ls, df, mount (UNIX); Explorer (windows)

File system

Process • • • Unit of execution User and kernel mode Context: stack, registers, PC thread Virtual memory – physical memory ps (UNIX); Process Explorer (Windows)

Process Management

Scheduling Algorithms • • FCFS Scheduling Round Robin Scheduling Priority Scheduling Multilevel Queue Scheduling Multilevel Feedback Queue Scheduling SJF Scheduling SRT Scheduling

IO subsystem • • Open, close, read, write Character device – ioctl Block device – strategy Major, minor device number Stream – full duplex connection Buffer cache Memory mapped IO

Inter process communication • • • Messages (msg*) Shared memory (shm*) Semaphores (sem*) Sockets Pipes

Windows 8 features Metro User Interface Internet Explorer 10 Apps and App Store New Hardware and Form Factors – multitude of devices (touch is primary interface) • Security Changes • Storage Changes (de-dupe, live disk repair) • Virtualization Changes • •

Hardware Virtualization