OS/2 CS Operating Systems Section 3 Fall 2003 By Keith Ancowitz Brian Henderson James Mauss Danielle Miller Kyle Nevins

Outline OS/2 History File Management System Memory Management Process Management Scheduler

OS/2 Warp History OS/2 1.0 Began as a joint venture with Microsoft to replace the current DOS 3.x system. OS/2 1.1 First implementation of a GUI in the operating system. OS/2 1.3 First version of OS/2 released by IBM without Microsoft’s assistance. OS/2 2.0 First version of the 32-bit system. OS/2 2.1 Released to allow users to have Windows 3.1 compatibility. OS/2 Warp 3.0 First version of Warp to appear. OS/2 Warp Connect P2P functionality and networking support. OS/2 Warp 4.0 Included Java and VoiceType

OS/2 vs. DOS File Systems OS/2 v1.2DOS File System High Performance File System (HPFS)File Allocation Table (FAT) Max. Characters in Filename Filename Format Capable of multiple extensions of varying lengths. This.my.filename 8dot3 (8 character filename and a single 3 character extension) Max. Path Length File and Dir Tracking Sector LevelCluster Level File Attributes Last Modified, Type of Data Stored, Native Language, etc. Min. Allocation Unit Sector (512 bytes) ≈ file node (FNODE)Cluster (4kb or more) Directory Structure Sorted Binary TreeUnsorted Linear List Caching Technique Store entire file and dir structure in cache File System Update Installable File SystemN/A XCOPY for a 5 MB file 21.6 Seconds39.4 Seconds Build an index of 4600 records in a 2.3 MB file 161 Seconds973 Seconds

Installable File System

 13 bit number for the segment number  1 bit to tell which table to look in LDT or GDT  2 bits to deal with protection Segment Table Page offsetPage Number Page Directory Page Table Page Frame Physical Address 32 SelectorOffset + Linear Address Memory Management

SMP Symmetrical Multi-Processing Testing Applications Increased Performance for Cheaper “Greatest Advantage” of OS/2 over Windows

Process/ Page Life Cycle

Process Scheduling RING 3 Scheduling –Four types of threads Normal Level –32 microseconds Time Critical –8 microseconds Idle-time Foreground Server –Priority and Round Robin

RING 0 Scheduling –Same Levels –Contexts Init Mode Interrupt Mode –Highest Priority –Dependant on IRQ levels Kernel Mode Process Scheduling