Opinion by Steven J. Vaughan-Nichols

Say goodbye to the MS-DOS command prompt

It had a good 36-year run, but its day is done

Computerworld |

ibm pc dos 1.0 screenshot
Public domain / Wikimedia Commons

Editor's note: After this article was published, Microsoft issued a statement clarifying that cmd.exe will not be going away after all. Read Steven J. Vaughan-Nichols' follow-up column.

My very first technology article, back in 1987, was about MS-DOS 3.30. Almost 30 years later, I'm still writing, but the last bit of MS-DOS, cmd.exe — the command prompt — is on its way out the door.

It's quite possible that you have been using Microsoft Windows for years — decades, even — without realizing that there's a direct line to Microsoft's earliest operating system or that an MS-DOS underpinning has carried over from one Windows version to another — less extensive with every revision, but still there nonetheless. Now we're about to say goodbye to all of that.

Interestingly, though, there was not always an MS-DOS from Microsoft, and it wasn't even dubbed that at birth. The history is worth reviewing now that the end is nigh.

Back in 1980, the ruling PC operating system was Digital Research's CP/M for the z80 processor. At the same time, Tim Patterson created Quick and Dirty Operating System (QDOS). This was a CP/M clone with a better file system for the hot new processor of the day, the 8086. At the time, no one much cared.

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Until, that is, IBM decided to build an 8086-based PC. For this new gadget, IBM needed to settle on programming languages and an operating system. It could get the languages from a small independent software vendor called Microsoft, but where could it get an operating system?

The obvious answer, which a 25-year-old Bill Gates seconded, was to go straight to the source: CP/M's creator and Digital Research founder, Gary Kildall. What happened next depends on whom you believe. But whether Kildall was really out flying for fun when IBM came by to strike a deal for CP/M for the x86 or not, he didn't meet with IBM, and they didn't strike a deal.

So IBM went back to Microsoft and asked it for help in finding an operating system. It just so happened that Paul Allen, Microsoft's other co-founder, knew about QDOS. Microsoft subsequently bought QDOS for approximately $50,000 in 1981. Then, in short order, IBM made it one of the PC's operating systems, Microsoft renamed QDOS to MS-DOS, and, crucially, it got IBM to agree that Microsoft could sell MS-DOS to other PC makers. That concession was the foundation on which Microsoft would build its empire.

Late last month, in Windows 10 Preview Build 14791, the command prompt was put out to pasture. Dona Sarkar, head of the Windows Insider Program, wrote, "PowerShell is now the defacto command shell from File Explorer. It replaces Command Prompt (aka, cmd.exe)."

That "defacto" suggests that it's not all over for the command prompt. And it's true that you can still opt out of the default by opening Settings > Personalization > Taskbar, and turning "Replace Command Prompt with Windows PowerShell in the menu when I right-click the Start button or press Windows key+X" to "Off."

But you might as well wave bye-bye to the old command prompt. Build 14791 isn't just any beta. It's the foundation for the Redstone 2 upgrade, a.k.a. Windows 10 SP2. This is the future of Windows 10, and it won't include this oldest of Microsoft software relics.

PowerShell, which just turned 10, was always going to be DOS's replacement. It consists of a command-line shell and a .Net Framework-based scripting language. PowerShell was added to give server administrators fine control over Windows Server. Over time, it has become a powerful system management tool for both individual Windows workstations and servers. Command.com and its NT-twin brother, cmd.exe, were on their way out.

They had a good run. A good way to understand how they held out for so long is to look at DOS as a house under constant renovation.

First, all there was was the basic structure, the log cabin, if you will, of Microsoft operating systems. That log cabin was given a coat of paint, which is what Windows 1.0 amounted to — MS-DOS all the way, with a thin veneer of a GUI. Over time, Microsoft completely changed the façade in ways that made the old log cabin completely unrecognizable.

With Windows NT in 1993, Windows started replacing the studs and joists as well. Over the years, Microsoft replaced more and more of MS-DOS's braces and joints with more modern and reliable materials using improved construction methods.

Today, after decades, the last pieces of the antique structure are finally being removed. All good things must come to an end. It's way past time. Many security problems in Windows trace back to its reliance on long-antiquated software supports.

Still, it's been fun knowing you, MS-DOS. While you certainly annoyed the heck out of me at times, you were also very useful back in your day. I know many programmers and system administrators who got their start with you on IBM PCs and clones. So, goodbye and farewell.

While few users even bothered to look at you these days, you helped launch the PC revolution. You won't be forgotten.

Steven J. Vaughan-Nichols has been writing about technology and the business of technology since CP/M-80 was the cutting-edge PC operating system, 300bps was a fast Internet connection, WordStar was the state-of-the-art word processor, and we liked it!

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