Re: Shutdown vs. Restart

On Sat, 22 Mar 2025 13:41:40 -0400, Newyana2 wrote :

   There is a disturbing new version of Sleep

Always striving to add technical value since I'm a purposefully helpful
guy, Newyana2 is correct. For modern Androids, there can be sleep states...
a. Standby
   The screen is off and some background processes are suspended.
b. Doze
   Which has different levels depending on the hardware.
c. Hibernate
   Which saves the current state to storage.
AFAIK, in the context of Android, and in the context of the next level... 1. Poweroff closes apps & processes & clears RAM.
2. Restart closes apps & processes & clears RAM.
3. And there are a few states in between those two.
A key difference is the bootloader is intimately involved in the
poweroff:startup, whereas the bootloader "may" not be involved in the
typical restart process. Moreover, "bootloader mode" is in between.
AFAIK, there are also low-power data-collection hubs in modern Androids
which are actually processors that are independent of the main SoC which
collect data from sensors (accelerometer, gyroscope, magnetometer, etc.).
Note that "trackers" take advantage of some of those low-power states.
For example, in an iPhone, the tracking happens even when the user "thinks"
he has fully turned off his phone (but the battery is still inside it).

   I've heard that some cellphones can no longer be turned off
or "powered off".

In the context of the next level, there exists a reduced-power state called
the "battery saver mode" which is the "appearance" of being turned off,
when it's not really off.
In fact, some hardware is always powered, AFAIK, given all Androids (AFAIK)
can charge even when the phone appears to be powered off and some have
always-on sensors (like accelerometers) which operate in very low-power
states (as likely do real-time clocks which keep track of time even when
the main OS is off).
As I alluded to, there's an in-between "bootloader mode" or "fastboot mode"
(which is actually a communication protocol) which is a distinct state from
the reboot/restart modes as it provides low-level access to the firmware.