Jackson Behling Robert Barclay GROUP ‘I’ OS/2(eCom Station) Jackson Behling Robert Barclay GROUP ‘I’

A Short History

Microsoft and IBM Buddies? The name OS/2 is short for “Operating system 2” Microsoft and IBM began to work jointly on OS/2 in 1985 First iteration was text mode only OS like DOS, but had a very rich API for keyboard and video. Why was it better than DOS? Multitasked text sessions ctrl+esc Protected Mode successor to DOS and MS Windows

The Presentation Manager GUI OS/2 Warp Screenshot Delivered in 1988 Almost identical interface to Windows TCP and Ethernet Support built into the OS OS/2 was supposed to be the successor to Windows 3.0

The Breakup Windows 3.0 became huge success This is probably because most PC manufacturers included this OS on their machines. Which meant that more hardware manufacturers would write drivers for Windows instead of OS/2 Microsoft and IBM had many small disputes and Microsoft went where the money was. IBM took OS/2 and optimized it for Servers, while Microsoft took NT OS/2 and developed it into windows NT

32-bit, Dos, and Windows Compatibility A 32-bit/16-bit hybrid was released in 1992. With the release of the 80386 Intel processor OS/2 2.0 could run DOS programs within a virtual machine. Windows 3.x could be ran within that DOS virtual machine because Windows ran on top of DOS

WARP 9! IBM added the name WARP to all of the later releases of OS/2 because of the popularity of Star Trek during the 90s Last release by IBM was 4.52 in December 2001 for Desktops and Servers. IBM stopped selling OS/2 December 23, 2005. And stopped support December 31, 2006

eComStation Serenity Systems took over development of OS/2 in 2001 under the new name of eComStation Last full release was in 2004. The new eComStation 2.0 is still in the Release Canidate stages at this time.

Kernel & System Architecture Preemptive multitasking. Multithreading. Inter-process communication (IPC) features such as shared memory, pipes, queues and semaphores. Virtual memory support (swapping) - theoretically up to 1GB virtual memory. Fully protected operation. Dynamic linking (DLLs). Support for 16MB physical memory

Protected Mode vs. Real Mode DOS still ran in real mode at that time, which meant no memory protection, only 1mb of memory to work with, and peripheral hardware had to be accessed directly. Protected mode was supported by the 286 and newer processors. Protected mode allows OS/2 to do Virtual memory, paging, and safe multitasking. Protected mode also protected the System from your OS and bad programs. If a program crashes, it won’t crash your OS or hard lock the system.

OS/2 File System Originally used the FAT file system. The Fat File system was not adequate for server based performance. Developed HPFS as an alternative to boot performance, and solve some of the inherent issues with FAT.

HPFS OS/2 Native File System. Support for long file names (up to 254 characters) and mixed-case file names. Directory positioned through the disk. Fat had it clumped at one end. Faster file creation. More efficient use of disk space, since files are stored on a per-sector basis instead of using multiple-sector clusters. Allocation of individual sectors at 512 bytes. Better performance due to overall design, including an internal architecture designed to keep related items closer to each other on the disk volume. Less fragmentation of data over time, and less need to defragment the file system. Uses more system memory.

Death of HPFS Considering how much more advanced it was than FAT, one might have thought that HPFS would have become quite popular. Unfortunately, HPFS was tied inextricably to OS/2, and for a number of reasons, many of them related to the politics between IBM and Microsoft, OS/2 never really became what it could have been. As interest in OS/2 died, so did support for HPFS. Many of the features of HPFS appear to have been incorporated into NTFS by Microsoft, or at least NTFS has some definite similarities to HPFS.