Hello Enthusiacs.  Today I’m taking a request and talking about backward compatibility.  I’ll try to keep it interesting, but if this gets a bit dry blame Baron Fang, it was his idea.

Get under there, Baron Fang, right under the Bus.

What do you think of when you hear “backward compatibility”?  Most people probably think of something like the a Blu Ray player also playing DVDs and CDs, a PS2 being backward compatible with the PS1, or the early DS platforms playing GBA cartridges.  Others might get upset that the PS3 was able to play PS2 games, but that was removed along the way.

The fact of the matter is that maintaining backward compatibility is either amazingly difficult, or very expensive.

Backward Compatibility in Computers

For the amazingly difficult version, perhaps the best example is the “evil empire” themselves, Microsoft.  Think about it for a minute, how many different configurations of hardware are there out there for Windows?  How many different programs build for different operating systems?  So many that calling it “astronomical” is in no way hyperbole.  Yet, for the most part, you can get the great portion of Windows applications through time to run on newer devices.  This includes a lot of really important business level things, like databases, servers, and other types of commercial software.  On the consumer level, many there also still work, and for those that don’t just work there are often additional translation software, or emulators, that will keep the new hardware working with the old software.  Stuff like Dosbox.  Granted, those aren’t Microsoft products, but the fact is that in the end you can keep the hardware talking to that software.

Microsoft also maintains a LOT of backward compatibility for their old operating systems.  Windows XP was officially alive for 12 years.  It only ended support on April 8, 2014.  Microsoft kept updates coming for it to fix security vulnerabilities and bugs for XP through Vista, through 7, and well into 8.  XP was literally a great-grandparent to the current OS.

That’s PC, though.  Apple is easy to maintain backward compatibility because it’s a closed ecosystem.  They know their hardware, so they can keep everything stable, right?  Even for an environment like Apple, there can be some big problems to deal with.  In the 2000’s, Apple made the decision to switch from PowerPC CPU to an Intel CPU.  This was fully implemented in the transition between OS 9 and X.  They did a lot of work to try to keep things working in the transition, but when you change the CPU, particularly in a closed, static ecology like Macintosh, there are a lot of assumptions the software is built on that get tossed out the window.  In the end, emulators and translators weren’t good or cost effective enough and there were programs that simply had to be completely re-written to let them run on OSX.

For software to work, the kernel needs to be there to link the different pieces of hardware from different manufacturers to the software. Since Apple controls their hardware their kernel is much more efficient. Windows is much more open, must deal with a lot more CPUs, motherboards, and so forth, and the kernel must be modified for each of those. This helps facilitate backward compatibility with hardware.

Pages: 1 2 3