Windows 10: The developer who wrote Windows Task Manager reveals its secrets

The same core Task Manager app that David Plummer wrote in 1994 still ships with Windows 10 today.
Written by Liam Tung, Contributing Writer

David Plummer, the former Microsoft developer who wrote Windows Task Manager in the 1990s, has revealed the application's inner workings and hidden tricks. 

Windows Task Manager (TaskMgr) first shipped with Windows NT 4.0 in 1996, and anyone who's used Windows since then has probably used the app to check CPU load or to kill a process. 

As Plummer details in a post on Reddit, while working as a new developer at Microsoft's Redmond headquarters, he wrote Task Manager "at home in my den" around 1994. 

SEE: Office 365: A guide for tech and business leaders (free PDF)  

According to Plummer, the "NT silverback devs" – including Dave Cutler, the father of Windows NT – let him check Task Manager into the main Windows tree even though he was a "greenhorn". 

The secrets he has now shared about Task Manager were from when it shipped with Windows XP, but he says today it's the same core app in Windows 10. He designed Task Manager for resilience and to continue working even when resources are low or the app crashes.

As spotted by The Register, Plummer gave a talk about his work at Microsoft at the University of Regina in Canada, where he studied computer science before moving to Redmond to work at Microsoft on MS-DOS in 1993. 

He details his time at university when he rented computers he couldn't afford to buy and wrote programs in BASIC on one of Microsoft's BASIC interpreters

While at university, still not knowing if he would end up writing games or code for embedded systems, he read a copy of Hard Drive, the book about Bill Gates and the making of Microsoft. 

Because he was an Amiga enthusiast, Microsoft was always the enemy, he says.

"But I was still interested in learning about the story behind them. And once I got in to the book 'interest' is not the word I'd best use to describe it. Enthralled perhaps, or entranced. I don't actually know – but certainly fascinated by the people, the projects, the environment and how they got things done."   

Plummer says he knew he wanted to join Microsoft, but at the time it was receiving 100,000 job applications per year. He managed to snag an interview, which he recalls was "famously grueling". 

"You spend the entire day there. You start with an HR interview to make sure you're sane bathed, and if so, you're off to a series of five one-hour coding interviews where you stand at a whiteboard and you answer brain teasers and write C and assembly code until you can't go any further," says Plummer.

"They push you until they stump and/or break you, and then depending on how those first five go, you might make it to the 'As Appropriate' interview, which is the hiring manager. The answer is Boolean at each of these steps: Hire or No Hire. There are no maybes."

After passing an internship working on MS-DOS, he was given a Microsoft developer job that paid $35,000 a year. But he also got stock options. 

Before building Task Manager, and while working at Microsoft, he created the utility VisualZip on the side. A Microsoft employee who didn't know that Plummer already worked at Microsoft approached him about the program and the company ended up purchasing it and including it in Windows. 

Plummer said he wrote Task Manager as a shareware app that he planned to sell on the side, but ended up giving it to Microsoft. 

"When Dave Cutler saw [Task Manager] he agreed to let me check it into the product, so I donated that one to the cause."

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He offers several tips on Reddit for users running into problems with Task Manager. 

"If Task Manager ever hangs or crashes, start another by pressing ctrl-shift-esc. Winlogon will look for an existing instance and try to revive it for up to 10 seconds. If the old Taskmgr doesn't start making sense by responding with a secret code within that time, another one will be launched. That way, you're never without a Taskmgr as long as there are some resources available," he wrote. 

"If Task Manager ever becomes internally corrupted, kill/close it. Restart it while holding down Ctrl, Alt, and Shift, and Task Manager will reset ALL internal settings to factory fresh if it sees that key combo at startup."

Additionally, Ctrl-Shift-ESC will launch Task Manager without any help from the Windows Shell. 

"So if the Shell/Explorer is dead, use this key combo to bring up TM and then reset/restart the shell. Even if your tray is missing and gone, this combo should start it.

"If the shell can't start something or is hung, try Task Manager. It has a mode where it will load without ANY references to the shell32.dll and allow you to start programs like CMD.EXE without the start menu."

Plummer says he has, until recently, been volunteering to teach kids to program at school but now mostly works on his YouTube coding channel Dave's Garage.  

David Plummer's talk about his work at Microsoft at the University of Regina in Canada. Source: Dave's Garage/YouTube

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