A recent article on forbes.com quotes me on what many people find to be the surprising longevity of mainframe computers.
Don’t things in computing just get better and better – not to mention faster, smaller and less expensive? Which implies that after a few years of use, it’s just not worth keeping the old stuff around anymore? So we throw out (oops, please excuse me, we meticulously recycle…) the useless old stuff and bring in the cool, cost-effective new stuff, right?
Like most common wisdom in modern computing, this contains elements of truth, but isn’t quite right.
The element of truth behind this thought is the astounding continued progress of Moore’s Law, which posits that electronics gets smaller and faster at a rate that boggles the mind. This is what gives us iPhones and portable computers that have more speed and capacity than the room-sized mainframes of the past.
But there is more to computing than electronics. First of all, there is this little matter of physical devices that have mass and inertia, that no amount of Moore’s-Law-driven advance will free from the tyranny of the laws of physics. This leads to growing storage problems that Moore’s Law actually makes worse. See here for a description of the issue.
Second of all, there is this thing called software. Yes, software, the invisible-to-the-human-eye “stuff” that makes all that amazing electronics actually do something. Software is really hard, complicated stuff, like most things that are essentially mental, conceptual and invisible (think math). Once some software actually gets working well enough, sensible people are loath to change it. Even worse, the amazing increases in speed and capacity of electronics mask simply awful problems in software.
Building most real, practical production software tends to be a nightmare that rarely ends. Re-building software that more-or-less works is a nightmare in hell that visits all the circles of hell in round-robin. So if the credit card companies can process their transactions, and the software that gets the job done happens to be written in totally-out-of-fashion-squared COBOL that runs best on a mainframe – that’s a great reason for IBM to build a new implementation of the mainframe instruction set out of modern electronics (thus getting most of the benefits of all the advances), just so it can run the code. It’s kind of like a horse and buggy built out of modern materials and powered by a fuel cell – it looks funny, but it’s modern and efficient and gets the job done.
So, yes, the electronic part of computers get faster, better and cheaper. And the software seems to get better because it’s along for the ride, but it actually tends to get worse, which is why Paleolithic mainframes have been discovered, alive and working, in otherwise modern data centers.