Power Saving: Computer Standby

Any modern personal computer, and even more so its mobile version, allows the operating system to use a special method of shutdown, sometimes called "standby mode." The need for it is determined by the specifics of the computer and the preferences of the user. In general, this mechanism is quite convenient and it makes sense at least in general terms to familiarize with it, because it's not for nothing that a venerable software developer Microsoft actively supports it in every new system of its own.

What is the waiting mode? To put it briefly, it's a computer analogue of the standby mode of most electronic devices. Of course, with some specific reservations. There was a waiting mode for a long time, there is evidence of its use in the line of Win 9x, although the possibility of confusion in two terms - "waiting" and "sleeping" modes is not excluded.

So, when the user turns on the standby mode, the operating system disconnects all main power lines: the hard disk stops, the CPU is transplanted to an energetic "hungry ration" (the voltage is sufficient only for polling ports), the video card and other components are de-energized. The only exception is the RAM modules, they are supplied with the standby voltage necessary to maintain the cells in the state that was at the time of the transfer to standby mode. The total consumption is negligible (by the way, according to the latest standards, no more than 1 W). In this state, the computer will remain until the user presses the power button. As a result, all the blocks are turned on, and since the memory is saved, the work can be continued from the same place. In the truest sense: playing music will continue from the next second, and the mouse cursor will be in the same place on the screen where it was at the time of shutdown. Since the system does not need to be booted, the output from the standby mode occurs in a matter of seconds. Alas, there are two features, because of which the sleep mode was developed.

The first - the Windows operating system just gives the command to the system board to de-energize the components, and executes all the BIOS through the ACPI interface. Accordingly, in the BIOS there should be an item with mode settings (S1 - S3), and the required one should be included.

The second - even with the short-term disappearance of the mains voltage, all data contained in the memory is lost. After turning on the computer, the user will see a message about the incorrectly completed work, and all data will be lost. Conclusion: in Windows 7, you can use the waiting mode, but only if there are no problems with power supply or if there is a productive uninterruptible power supply.

But what about the sleep mode? He has no such drawbacks, as he works a little differently. When it is activated, a dump (an exact copy) of the memory is created and stored in a special file on the hard disk. After re-enabling, Windows does not load in the usual sense of the word, but restores its state from the dump. In this condition, the computer can be unlimited time. The disadvantage is a low performance, after all, writing / reading a file of several gigabytes is not instantaneous (downloading "from scratch" faster). Perhaps with the advent of SSD, the situation has changed, but the classic hard drives behave this way. However, programmers from Microsoft are not idle, so in new versions of Windows there was an interesting mode of hibernation. Its meaning in combining waiting and hibernation: if there was no power failure, then the work resumes under the standby mode, and if the contents of the memory cells lose, the mechanism for getting out of sleep mode comes into effect . Pretty handy.