For a long time, the idea that turning off a computer using the physical power button on its case is something bad has persisted. And like other things in the world of computing, the truth of that idea depends on certain details. In short, our systems are more intelligent and robust than they were years ago, and they almost always find a way to shut down correctly, but there are isolated occasions where a forced shutdown carries risks.
The Classic Warning
It’s likely that many of our readers remember this:
This was the classic warning that Windows 9x systems presented to the user once everything was ready to safely turn off the computer. That required pressing the 'Power' button, or on older systems, toggling the switch. On the old XT and AT platforms, the button was nothing more than a direct electrical cut. The brown and blue wires brought 'live' and 'neutral' (so to speak) from the wall, passed through the switch, and returned to the power supply through the white and black wires. There was no 'soft off', nor scheduled power-on or power-off (or rather, not without additional hardware). Fortunately, everything changed with the development of the ATX and ACPI standards, which we remember very well for its painful and frustrating partial implementation in Windows 98.
The Risks of Forced Shutdown
That era burned into our minds the risk of turning off a computer with the button without the proper process. Basically, all hard drives are exposed, with possible general data loss (I've seen partitions vanish into thin air), corruption in the boot sector (preventing the correct start of the operating system later), corrupted files, orphaned blocks, or a combination of these symptoms. In the best case, nothing was lost, and Windows would run a ScanDisk session at startup to verify the integrity of the volume... something that still exists in its own way, because forced shutdown hasn't gone anywhere. By holding the power button for four seconds, the 'poweroff' command is immediate.
The Modern Power Button
And there’s the key: Today, the button generates a signal that is equivalent to a shutdown command for the operating system. It’s even possible to reprogram that order through power options to indicate suspend or hibernate. A single press of the button is perfectly safe, but Windows will warn about any unsaved work, or those programs that for various reasons prevent a full shutdown. Pressing the reset button or doing the four-second cut are the riskiest, although in most situations, the damage can be repaired (for example, the classic blue screen unmountable_boot_volume only requires a quick session with chkdsk from an installation disk).
