Forty years. Thousands of IT products. Many of them made a huge difference for technology professionals, and they’re fondly remembered. But only a few truly transformed IT — and how IT people, users and businesses did their work. Here are 10 IT products that changed everything.

Dynamic RAM: IBM invented it, but Intel Corp. sold the first commercial DRAM in 1970. Within two years, it was outselling the magnetic core memory that had been the standard since the 1950s. And unlike core memory, DRAM was subject to Moore’s Law: Over time, it just got cheaper and more plentiful.

Ethernet: It bubbled up out of Xerox PARC, became a standard in 1980 and soon overran proprietary protocols to become the overwhelmingly dominant networking connection for PCs and servers.

IBM System/370: In 1964, with its System/360 mainframe, IBM promised that customers wouldn’t have to rewrite their software when they bought the next version of the machine — it would be compatible. That was a revolutionary concept. In 1971, the S/370 kept that promise and, in the process, sealed the doom of IBM’s mainframe competitors. Of course, that never-have-to-rewrite compatibility also created the Y2k problem.

IBM Personal Computer: In 1981, the PC transformed the desktop computer from something users smuggled in (the Apple II running VisiCalc) to a corporate IT standard. It also gave users control over their computing that they would never give up.

Apple Mac­intosh: In 1984, the Mac transformed users’ expectations of how friendly computers should be. The result: mice, graphical interfaces, plug-and-play peripherals and a knockoff from Microsoft called Windows.

SAP R/3: Remember when data processing departments built their own financial accounting software? Starting in 1992, SAP AG wiped out the need to maintain all that code — and it was Y2k-compliant, too.

Salesforce.com: Software as a service proved out. If SAP offered “buy instead of build,� in 1999 Salesforce.com offered “rent.�

Linux: And if Salesforce.com is “rent,� Linux is “get it free.� More important, since first appearing in 1991, Linux has shown that major pieces of IT infrastructure can be developed by large groups of loosely organized programmers.

Netscape Navigator: It wasn’t the first popular Web browser — that was NCSA Mosaic. But when Mosaic creator Marc Andreessen added cookies in 1994, Netscape turned the Web into a worldwide marketplace.

BlackBerry: The cell phone meant users could always be connected, but starting in 1999 with Research In Motion Ltd.’s BlackBerry, users would always be connected to their e-mail — and the era of the 24/7 knowledge worker truly arrived.

I'v always been a big fan of Apple, having owned Macs for home, academic and business use for 20 years (except in the lab - historically had poor interfacing). However, it must be said that they did not invent graphical interfaces, as good as theirs have been. The Xerox Alto computer, and thus that company should probably be given the accolade. The Alto was a research tool and not strictly a widely available PC.

Power to the Mac!

Nice rundown of IT software/hardware over the last 40 years, I was expecting a more general list. I feel there are other items of interest, one of which is Microsofts new XNA game development platform.

So, what will the next top 10 IT products would you speculate will be? How about a brain chip that connects all internet users "hands-free"? Equiped with brain sensory connections (user-optional, of course!) for a true computer-free e-interface?