The author may just be showing their age a bit. That's what Ctrl+Alt+Del does on modern versions of Windows, but from Windows 95 to Windows XP (inclusive) it directly launched the Task Manager.

Ctrl+Alt+Del on an IBM PC or a compatible clone reboots the machine no questions asked. There's a dedicated reset button in case that fails.

Doing anything other than a reboot started with protected mode MS-Windows 3.1 IIRC (then marketed as "386 enhanced mode").