5 ms·

That is not a good answer. It's perfectly possible for computers to boot in a fraction of a second. The argument that computers need to go from a useless state

by diego 7y ago

That is not a good answer. It's perfectly possible for computers to boot in a fraction of a second. The argument that computers need to go from a useless state S0 to a useful state S1 and that takes a long time is just bullshit. The question is, how close can you bring S0 to S1. This is a question of optimization. What happens is that S1 is different for different computer configurations, and processing needs to happen. Then the question becomes, how much effort do software companies spend optimizing that processing? The answer is "as much as they feel that they need to." Computer boot times have been constant over many years because performance gains enable companies to add more features. As long as the boot time stays within tolerable bounds for the typical user, there is no need to optimize further. But there are tons of other computer systems in the world (particularly embedded) that must boot instantly, and they do so.

fulafel 7y ago
I think the same answers hold for a large set of "what's stopping us from making computers better in dimension X". You can explain the cause of the unsatisfactory state as lack of incentives and software inertia, and you can also say that it's fixable at a cost.
colejohnson66 7y ago
It depends on if you consider the Arduino and other related devices “computers”, but their init routine takes a fraction of a second before control is passed off to the user’s code
petra 7y ago
// What happens is that S1 is different for different computer configurations, and processing needs to happen. The computer and OS config doesn't change often. And it's doesn't seem slow to test that. So caching at boot should work. And caching is a low effort optimization. So it should have been implemented early. But we don't have caching at boot, why?
- salawat 7y ago
  The two hard things in computer science are naming things, and cache invalidation. Remember; the computer could quite literally have been completely reconfigured out from under the BIOS. Testing that everything is the same from the computer's point of view is anything but straightforward. Also, most recognizable boot time isn't spent waiting on BIOS and POST; it's spent waiting for either the boot loader, disk encryption, or the OS to spin up all the background stuff (graphics stacks, session managers, HAL's, message busses, desktop environments, network services... etc) it needs to offer for fulfilling the particular purpose the system is intended for. Computation is amazingly fast, but by no means either free or magic. Everything takes time. However, I make no excuses for Windows: They had 3-5 second boot nailed for a while. Then, they done bloated it to the point of unrecognizability.
  - egypturnash 7y ago
    Usually the configuration stays the same, though - why not a way for the user to indicate when it has? Hold down an awkward combination of three far-flung keys while booting, the BIOS wakes up and checks every device plugged into it, otherwise it just pulls it in from a cache. (And how much does the average computer's config change? How many users never change a single part of the hardware configuration of their computer for its entire lifetime? A hobbyist who built their own might swap out CPU/GPU/drive/ram/etc, but how many people upgrade their laptops in any way?) Get all that backup stuff spun up. Save the state of the entire computer the same way you're saving a hibernation snapshot. Next boot, just pull that snapshot up. Something makes that snapshot crash? Reset and run the slow boot, either because the system caught this, or because the user held down the "invalidate bootup snapshot" chord. Although realistically I never reboot my computer any more unless I'm doing an OS upgrade anyway. It's all just "sleep" and "wake up" nowadays for me, so I don't care if bootup adds a minute or two to the end of the half an hour or so my computer spent downloading the update and applying it. Maybe a cold boot just isn't worth optimizing any more.
    - cududa 7y ago
      As someone who worked on boot up sequence in Windows, that won’t work. You could kill components in the system if someone forgets to press the right keys on bootup. The snapshot method you mention is essentially how it already works
mbell 7y ago
> It's perfectly possible for computers to boot in a fraction of a second. Maybe if you are restricting to software and time from 'hardware ready', but I doubt this is possible from power application. There are a lot of hardware processes that need to take place before any real code can execute, e.g. locking clocks, memory training, etc.
- Dylan16807 7y ago
  Okay, how about we budget half a second for hardware and half a second for software? (assuming SSDs) How long does memory training need?

by diego 7y ago

fulafel 7y ago

I think the same answers hold for a large set of "what's stopping us from making computers better in dimension X". You can explain the cause of the unsatisfactory state as lack of incentives and software inertia, and you can also say that it's fixable at a cost.

colejohnson66 7y ago

It depends on if you consider the Arduino and other related devices “computers”, but their init routine takes a fraction of a second before control is passed off to the user’s code

petra 7y ago

// What happens is that S1 is different for different computer configurations, and processing needs to happen. The computer and OS config doesn't change often. And it's doesn't seem slow to test that. So caching at boot should work. And caching is a low effort optimization. So it should have been implemented early. But we don't have caching at boot, why?

salawat 7y ago
The two hard things in computer science are naming things, and cache invalidation. Remember; the computer could quite literally have been completely reconfigured out from under the BIOS. Testing that everything is the same from the computer's point of view is anything but straightforward. Also, most recognizable boot time isn't spent waiting on BIOS and POST; it's spent waiting for either the boot loader, disk encryption, or the OS to spin up all the background stuff (graphics stacks, session managers, HAL's, message busses, desktop environments, network services... etc) it needs to offer for fulfilling the particular purpose the system is intended for. Computation is amazingly fast, but by no means either free or magic. Everything takes time. However, I make no excuses for Windows: They had 3-5 second boot nailed for a while. Then, they done bloated it to the point of unrecognizability.
- egypturnash 7y ago
  Usually the configuration stays the same, though - why not a way for the user to indicate when it has? Hold down an awkward combination of three far-flung keys while booting, the BIOS wakes up and checks every device plugged into it, otherwise it just pulls it in from a cache. (And how much does the average computer's config change? How many users never change a single part of the hardware configuration of their computer for its entire lifetime? A hobbyist who built their own might swap out CPU/GPU/drive/ram/etc, but how many people upgrade their laptops in any way?) Get all that backup stuff spun up. Save the state of the entire computer the same way you're saving a hibernation snapshot. Next boot, just pull that snapshot up. Something makes that snapshot crash? Reset and run the slow boot, either because the system caught this, or because the user held down the "invalidate bootup snapshot" chord. Although realistically I never reboot my computer any more unless I'm doing an OS upgrade anyway. It's all just "sleep" and "wake up" nowadays for me, so I don't care if bootup adds a minute or two to the end of the half an hour or so my computer spent downloading the update and applying it. Maybe a cold boot just isn't worth optimizing any more.
  - cududa 7y ago
    As someone who worked on boot up sequence in Windows, that won’t work. You could kill components in the system if someone forgets to press the right keys on bootup. The snapshot method you mention is essentially how it already works

mbell 7y ago

> It's perfectly possible for computers to boot in a fraction of a second. Maybe if you are restricting to software and time from 'hardware ready', but I doubt this is possible from power application. There are a lot of hardware processes that need to take place before any real code can execute, e.g. locking clocks, memory training, etc.

Dylan16807 7y ago
Okay, how about we budget half a second for hardware and half a second for software? (assuming SSDs) How long does memory training need?