6 ms·

Laptops, mostly, to maximize battery life. If I'm going on a flight, I'll charge and hibernate my system at home, bag it, then drive to the airport and get thro

Laptops, mostly, to maximize battery life. If I'm going on a flight, I'll charge and hibernate my system at home, bag it, then drive to the airport and get through security. This is about a 2 hours process and entails zero battery drain.

jeffbee 6y ago
But what's the real value over a cold boot? Wake from hibernate takes a lot longer than a cold boot, and to me it doesn't seem to save any time.
- watermelon0 6y ago
  You don't lose open apps, files, tabs, etc., so your work is not interrupted. I've not perceived any time difference between cold boot and wake from hibernation, on a decently fast SSD.
- l3s2d 6y ago
  Which OS are you using? I've never noticed a difference between cold boot and hibernate on Linux.
  - jeffbee 6y ago
    Are you sure you're including the amortized lifetime cost of whatever you had to do / whatever you will have to do to troubleshoot Linux resume-from-disk? I kid, but I do use Linux, it's just a Linux that doesn't even offer hibernate and boots cold in one second: ChromeOS.
  - bscphil 6y ago
    Anecdata: back in the days when I was using Ubuntu (pre-Unity) on what was even at the time moderately old hardware, there was an obvious difference. Standard bootup took 20-30 seconds, resuming from hibernation took multiple minutes. Just thinking about it on an abstract level, it's not that unintuitive that resuming from hibernation should be slower than both cold boot and resuming from sleep. When you cold boot you need to load the kernel and startup programs into memory. With hibernation you need to load the whole previous operating state into storage, which is going to mean multiple GBs need to be read from your swap partition into memory. It's not hard to imagine that on many systems the hard drive will be the slowest piece of hardware.
deathanatos 6y ago
But over suspend to RAM? Suspend to RAM eats through basically zero battery, and can trivially survive the plane flight. (I've taken my laptop on flights, drained the battery to <10% in the course of the flight, and had it spent the last several hours in suspend-to-RAM.) (There might be some discussion about security in America's airports, and their overzealousness towards illegal searches, and on that basis, I'd entertain hibernation as superior.)
- ravi-delia 6y ago
  If you suspend to RAM, and there's some kind of failure, you lose everything, likely leaving some things in a bad state. Hibernation is way less likely to have something like that happen. Of course, the best of both worlds is Suspend then Hibernate.
  - fignews 6y ago
    What do you mean by lose everything? AFAIK, suspend syncs the disks so there really shouldn’t be any half-written data.
    - kljbjklkjhjkl 6y ago
      Everything being "the contents of ram and the running system image". Suspend to ram doesn't write the contents of ram to disk, it keeps the ram active, constantly refreshing it. Hybrid Suspend will suspend to ram, then additionally write the contents of ram to disk, so that the image can be resumed in the event of a power failure. The "resume" codepaths in this case are literally the same as if you'd just hibernated.
      - deathanatos 6y ago
        I interpreted that as "syncs the disks", as in, flushes the buffers. (which it does, I believe, do.) A failure to suspend from RAM isn't that harmful: it's just an unscheduled reboot, as if you'd suddenly removed power. The wording they're responding to is pretty vague: "lose everything". What is "everything"? E.g., the filesystem state is in good order. And even though RAM gets reset, many applications, like Firefox, will usually simply realize what happened, and recover.

jeffbee 6y ago

But what's the real value over a cold boot? Wake from hibernate takes a lot longer than a cold boot, and to me it doesn't seem to save any time.

watermelon0 6y ago
You don't lose open apps, files, tabs, etc., so your work is not interrupted. I've not perceived any time difference between cold boot and wake from hibernation, on a decently fast SSD.
l3s2d 6y ago
Which OS are you using? I've never noticed a difference between cold boot and hibernate on Linux.
- jeffbee 6y ago
  Are you sure you're including the amortized lifetime cost of whatever you had to do / whatever you will have to do to troubleshoot Linux resume-from-disk? I kid, but I do use Linux, it's just a Linux that doesn't even offer hibernate and boots cold in one second: ChromeOS.
- bscphil 6y ago
  Anecdata: back in the days when I was using Ubuntu (pre-Unity) on what was even at the time moderately old hardware, there was an obvious difference. Standard bootup took 20-30 seconds, resuming from hibernation took multiple minutes. Just thinking about it on an abstract level, it's not that unintuitive that resuming from hibernation should be slower than both cold boot and resuming from sleep. When you cold boot you need to load the kernel and startup programs into memory. With hibernation you need to load the whole previous operating state into storage, which is going to mean multiple GBs need to be read from your swap partition into memory. It's not hard to imagine that on many systems the hard drive will be the slowest piece of hardware.

deathanatos 6y ago

But over suspend to RAM? Suspend to RAM eats through basically zero battery, and can trivially survive the plane flight. (I've taken my laptop on flights, drained the battery to <10% in the course of the flight, and had it spent the last several hours in suspend-to-RAM.) (There might be some discussion about security in America's airports, and their overzealousness towards illegal searches, and on that basis, I'd entertain hibernation as superior.)

ravi-delia 6y ago
If you suspend to RAM, and there's some kind of failure, you lose everything, likely leaving some things in a bad state. Hibernation is way less likely to have something like that happen. Of course, the best of both worlds is Suspend then Hibernate.
- fignews 6y ago
  What do you mean by lose everything? AFAIK, suspend syncs the disks so there really shouldn’t be any half-written data.
  - kljbjklkjhjkl 6y ago
    Everything being "the contents of ram and the running system image". Suspend to ram doesn't write the contents of ram to disk, it keeps the ram active, constantly refreshing it. Hybrid Suspend will suspend to ram, then additionally write the contents of ram to disk, so that the image can be resumed in the event of a power failure. The "resume" codepaths in this case are literally the same as if you'd just hibernated.
    - deathanatos 6y ago
      I interpreted that as "syncs the disks", as in, flushes the buffers. (which it does, I believe, do.) A failure to suspend from RAM isn't that harmful: it's just an unscheduled reboot, as if you'd suddenly removed power. The wording they're responding to is pretty vague: "lose everything". What is "everything"? E.g., the filesystem state is in good order. And even though RAM gets reset, many applications, like Firefox, will usually simply realize what happened, and recover.