Chapter:Chapter 01 – What is an Operating System and Why is it Important?
Subsection: 04. Introduction to Operating Systems
Topic: OS/2 Warp from a Programmer’s Viewpoint
Date Composed: 12-28-96 06:27:11 PM Date Modified: 12-29-96 12:41:01 PM
Long Term Compatibility
It is important to note that one very compelling feature of OS/2 is visible only to programmers. Warp has a very stable set of APIs (Application Programming Interface). An API is an interface through which programmers use a high level language to access operating system functions and data.
Although the API function set of OS/2 has grown over the years, it has remained remarkably stable and consistent. Programs written on and for very early versions of OS/2 will still run properly on today’s Warp 4 and on tomorrow’s versions of OS/2, whatever they might be called.
I am not a programmer, although I program a little bit so that I can more fully understand the inner workings of OS/2. I wrote a very small C language program several years ago under OS/2 1.1 using the tools available at that time. This was a simple Presentation Manager (GUI) program which created a window on the desktop in which was displayed some information about the operating system and disk drive usage. I used the API functions available at that time to obtain the operating system and disk data. That little program still runs today on Warp 4 with no errors and with the same correct results as I obtained on OS/2 1.1. The reason is the consistency of the OS/2 APIs.
IBM believes that customers (and programmers are part of the customer set for any operating system) should be able to expect long term consistency and backwards compatibility in the products they buy from IBM. That means that programs which ran last year or two years ago or last month, should run today and should still run tomorrow. It means that complete code rewrites should not be required every time the operating system is upgraded. Actually IBM believes this about its hardware, too. There are IBM ES/9000 systems which are still running programs written for the System/360 back in the 1960s. This is due to the backwards compatibility of IBM’s hardware and operating systems.
IBM brings this same compatibility to the desktop with OS/2 Warp. Not only can it run the programs written for early versions of OS/2, it can run almost every DOS and Windows 3.x program ever written. That is more programs than any other operating system on the face of the planet.
There have been about as many versions of Windows to date as there have of OS/2. OS/2 has at least 10 major version releases not counting CSDs and Fixpaks:
- OS/2 1.00
- OS/2 1.10
- OS/2 1.20
- OS/2 1.30
- OS/2 2.00
- OS/2 2.10
- OS/2 2.11 for Windows
- OS/2 2.11
- OS/2 Warp for Windows
- OS/2 Warp
- OS/2 Warp Connect
- OS/2 Warp Connect for Windows
- OS/2 Warp 4
- OS/2 Warp Server
And almost every OS/2 program will run on all versions. Almost every DOS and Windows program will run on every version of OS/2 since 2.00.
Microsoft has invented a new set of APIs for almost every version of Windows it has ever produced. Programs written for Windows (V1) or Windows 286 will not run on any later versions of Windows. Windows 2.0 programs won’t run on Windows 3.1 or Windows 95 or Windows NT. Most Windows 3.1 programs will not run under Windows 95 or Windows NT.
Why? Because, in my opinion, Microsoft has no desire for their Windows products to be backwards compatible. Which company sells the most horizontal applications (spreadsheets, word processors, etc.) for Windows? Why, Microsoft, of course! Microsoft plays a game with the rest of the industry. Every time one or more of the horizontal application vendors competing with Microsoft approaches a significant market share, Microsoft announces a new version of Windows. And interestingly enough, each major new version is the proud possessor of a completely new API set.
Of course the Microsoft horizontal application programmers have access to the API before anyone else, and so their applications are available for the new operating system before anyone else’s. Big surprise!! So Microsoft leads the pack in market share right from the beginning.
Every time a major new version of Windows is released, every software vendor who wants to remain current must completely rewrite their application software.