14 ms·

Why can't computers boot instantly? (2013)

146 points by anon35 7y ago

mehrdadn 7y ago
More interesting question to me is why the hell some firmware boots take so long now. I know laptops from years ago much, much faster than what I have now, which is otherwise much faster than them. And the firmware initialization times for some servers I've seen seem completely obscene (on the order of minutes).
- aardvarklegend 7y ago
  Surprisingly power is a huge factor. Spinning up 48/96 drives on boot can surge beyond what power supplies could handle, so things supported staggered spin ups. This allowed huge banks of drives to start without blowing a power supply, but you don’t know how many drives or if staggered spin up is enabled until it times out. This was a huge boot delay for servers.
  - mehrdadn 7y ago
    That's interesting to note, but I'm just talking about computers with 1 drive connected to them. Both for the servers and the laptops. In fact the older (faster) laptop had both a DVD and an HDD, whereas the newer one just has an SSD...
- gingabriska 7y ago
  Today we have to make things hack proof, noob proof and lots of proofing adds more complexity, cost and lowers speed.
  - mehrdadn 7y ago
    I don't think this is it. I haven't tried with many machines but I don't think current machines are all generally slow with firmware, just some of them. The part that baffles me is that the slowness is on the faster ones.
- scarejunba 7y ago
  Probably because no one turns anything off anymore so the selection pressure is gone.
  - gambiting 7y ago
    So I'm not so sure about that. When I complained recently about sleep issues on my windows 10 desktop I was met with an overwhelming "but....why are you sleeping your desktop? Just switch it off like a normal person?".
    - distances 7y ago
      Indeed. I've no idea if sleep works on my desktop. I've never tried.
verisimilitudes 7y ago
Windows is a bloated mess, so it's obvious there. As for anything POSIX, it's because UNIX is shitware; it took a long time to boot decades ago and it takes a long time to boot now, because more garbage has been piled on top. It's possible for a good operating system to boot in less than a second, however. People have simply been conditioned to accept this unacceptable state of affairs, no different than a TV that takes ten seconds to become usable for no reason other than the manufacturer was lazy.
- johnchristopher 7y ago
  While I don't agree with everything you wrote I would like to add android boot time to the list.
- galfarragem 7y ago
  I still remember the day I got a new TV (despite old CRT working) for my parents and see their faces the first time time we turned it on. Now they are used but at the beggining the boot time was difficult to grasp: it used to be negligible with the obsolete tech..
  - FrancoisBosun 7y ago
    There is now a boot time for my kitchen mixer… about 2-3 seconds. It’s horrible and I always forget.
    - sverige 7y ago
      Honestly, "smart" appliances are the worst idea since . . . I can't actually think of a worse idea.
      - brokenmachine 7y ago
        Recently I got an email ad for a "smart" kettle with an app that you can remotely turn the kettle on, or schedule a time for it to turn on...
  - 7y ago
mojuba 7y ago
A bigger question for me is, why can't monitors boot instantly? So annoying that a monitor that went to sleep can sometimes take 10-20 seconds longer to wake up than the computer it is attached to.
- quickthrower2 7y ago
  But my 5” touchscreen monitor can...
- gruez 7y ago
  If it's really 10-20s, I'm guessing it's because it's because it's cycling through the various input sources looking for a signal.
  - ebg13 7y ago
    But it could just look at all of the input sources at the same time. And anyway, these are solid state electronics, not hamsters and flywheels. Taking seconds to send "give me electrons" and for the other side to say "here are some electrons" is bonkers.
    - jamesissac 7y ago
      Being able to observe all inputs sources at the same time requires extra hardware(more utilisation of the FPGA resources), considering only one input is connected to the display at a time. So it's probable that the check is sequential.
      - lazyjones 7y ago
        I know you’re just guessing, but if that’s what happens, why don’t they just default to the last source used and start the cycling only if nothing is detected there?
      - ebg13 7y ago
        "More" isn't a meaningful qualifier without a quantifier. I'm not convinced that it would take more than $0.01 worth of resource. I could even see doing it in a purely analog fashion with an extremely basic component like a mosfet. If a pin goes high because the computer responded to your request to send electrons, it sets the corresponding channel. > So it's probable that the check is sequential. It's a user unfriendly design for the process to be "send request, wait 5 seconds, send request on next channel, wait 5 seconds, send request on next channel, ..." when it could instead be sending requests across all channels rapidly and then that getting a response on a particular channel _activates_ that channel by analogue means.
imtringued 7y ago
Because everything takes non zero time. If a state transition from turned off to booted takes no time then doesn't that mean there is no state transition at all? The only way for it to take zero time for a computer to boot is if it is already booted or there is no difference between an unbooted computer and a booted one. How much time does it take for a circle to become round? None at all. It happened instantly.
- jarfil 7y ago
  It also takes hours to compile everything from scratch, but we don't see computers taking hours to boot, do we? Most of the process "from initial state" is cached, and there is little reason to not keep the trend. Booting, as in detecting and initializing the hardware, including the RAM, should only be needed when hardware is changed, and even then it should be possible to cache the state of any unchanged parts.
Bakary 7y ago
A silver lining of long boot times is that you can contemplate what you are about to use the computer for and catch yourself in the middle of a habit loop.
- tsjq 7y ago
  haha. that's a good one.
- vendiddy 7y ago
  Can't tell if you're joking but actually like this idea.
- kalleboo 7y ago
  I bet adding a 15 second wakeup time to my smartphone would abort about 75% of my social media usage
argimenes 7y ago
When I was in high school their Amiga would cold boot into a GUI within 3 seconds. It was the same for the Acorn Archimedes in the UK. These computers had the entire GUI OS burnt into the ROM. After that I remember the shock or getting a 386 and waiting minutes for Windows 95 to load. It was like the future had died and was buried by a conspiracy of silence in the industry.
- unnouinceput 7y ago
  386 and W95? Not a good combination. By the time W95 was out on the market P5 was the latest and greatest and a 486 was the low budget one. You might want to reconsider those memories. As for loading times it all boiled down on how many check-up you wanted or not in your BIOS. As a rule I've always did memory check by BIOS only one time when buying/putting together a new PC and after that I've check it off in BIOS, halving the time it need it to boot. It was perfectly easy to have a 3 seconds BIOS time, sometime was even a nuisance to make it that short because you'd had to be fast to press Del (or whatever the BIOS key was) if you wanted to go to BIOS instead.
  - dmead 7y ago
    you're conflating a bunch of stuff here.
  - avian 7y ago
    > By the time W95 was out on the market P5 was the latest and greatest and a 486 was the low budget one. You might want to reconsider those memories. Maybe the 486 was the low end of what you could buy at the time, but not everyone bought a new computer. My parents upgraded their 386 from Windows 3.1 to 95. It was slow, but usable.
    - unnouinceput 7y ago
      In 3rd year at Uni, in good old '96 I had a P5 with W95 in my dorm room. Granted, not mine, but the friend and colleague who had it was not some rich parents kid, just middle class. We played HOMM2 on it all day long, much to his gf dismay.
basicplus2 7y ago
My old valve televisions are up and running long before ANY smart tv, AND its quicker to change channels
thrownhwn 7y ago
Has someone explored the area of writing software that spits out resume from disk images?
- amelius 7y ago
  You mean hibernation? That exists for a long time now, but is technically not booting.
  - jarfil 7y ago
    Alternatively, booting is just an inefficient "resume from disk", using a generic initial state instead of one adapted to the device.
CGamesPlay 7y ago
A lot of these answers are why computers don’t boot instantly but none really talk about why they can’t. The accepted answer talks about it on a physical/mechanical level but eschews practicality: what can’t computers boot arbitrarily quickly?
- enneff 7y ago
  They can. But the more software you need to initialise the slower it is. And modern machines run a lot of software.
  - maxheadroom 7y ago
    >...the more software you need to initialise the slower it is... Of course, part of that initialisation is self-tests, harkening back to the O.G. POST[0] days. [0] - https://en.wikipedia.org/wiki/Power-on_self-test https://en.wikipedia.org/wiki/Power-on_self-test
  - adsche 7y ago
    But then the questions are, why does it need to initialize? Why doesn't it start in an initialized state, what factors make it impossible to determine that initialized state beforehand and storing it? How close can we get?
    - silon42 7y ago
      The fact that reboots happen mostly when software (kernels, system) is upgraded is part of it. It's simplest and most reliable to initialize the system from clean state (I've often had an idea it would be best to reinstall Windows+software for each reboot).
      - adsche 7y ago
        Yes, but do you have an idea why that is, why is it so much more reliable to initalize every time than to generate an initialized configuration and reuse that? Developer errors? Not enough testing?
ohiovr 7y ago
My POST sequence takes longer than the boot process so no matter how blazing fast my drives are it still takes a long time to get to the boot loader.
- faissaloo 7y ago
  Nail on the head, UEFI/BIOS is increasingly the bottleneck for startup speeds nowadays
kzrdude 7y ago
I'm pretty happy with boot times, the longest wait is the boot loader and inputting the password. (Linux with full disk encryption).
thecopy 7y ago
Because of state.
sansnomme 7y ago
I have a question too: why does radios take so long to start up and acquire a signal? Same for other I/O devices similar to radios，on the embedded side you have keep on polling until finally it acquires the signal.
- simcop2387 7y ago
  One common thing is that the radio needs time for it's clock source to stabilize. To make them cheaper they usually use things like phase locked loops to take a lower frequency clock and multiply it up to the clock they need. This can take tens to thousands of milliseconds to bnot be bouncing around when first configuring the loop. And with modern radios, these loops get programed at run-time from the firmware because they need to be at a large range of frequencies. During this startup you can't transmit anything, because you'll transmit with another signal (the clock jitter) mixed in which adds noise, at best, and possibly even at a completely incorrect frequency which will result in fines or possibly jail time. The safe route is just to wait instead. Receivers work similarly, using PLLs to downmix the signal they want, generally, and while they can begin trying to receive while waiting on it to stabilize, it's usually pointless because you'll just be getting unintelligible garbage from the noise or wrong frequency.
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.
kstenerud 7y ago
There are a number of reasons: 1. Hardware Hardware is a big problem for boot times. Most hardware is poorly standardized, or not standardized at all, or doesn't even follow the standards, or tries to be backwards compatible with older hardware, or is just plain buggy. This means that the initialization code has to poll and retry and work around a whole bunch of things just in case the hardware happens to be slow in responding or gives a weird response. This is the main reason why POST is so godawful slow, and why the initial linux boot sequence takes so long. Apple hardware can boot quicker because they control what hardware is in the machine and can optimize their initialization code for it. 2. Software The operating system stack is HUGE. There's a LOT of state that needs to be initialized, and most of it is not very efficient (we tend to optimize the runtime operation vs the startup operation of a software package). You absolutely could cut the software component of an OS boot sequence by an order of magnitude, but the development costs would be massive, and the gains pathetic in terms of the work-over-time the machine will do over its lifespan. 3. Protocols A large number of the protocols we use for inter-process and inter-device communication have poorly designed latency characteristics. Either they are too chatty (requiring multiple messages back and forth to do a task), or have ill-defined timeouts (requiring clients to wait longer than they should), or ambiguous states, or some poorly built implementation has become the de facto standard. This is an area I'm personally tackling. 4. Formats We use a number of formats for the wrong kinds of things. Appending to a tgz file, for example, has horrendous time implications, especially as the archive size grows.
- catern 7y ago
  This is a really good summary of some of the main reasons - more interesting detail than many of the other comments here. Now what would really be interesting is if we had the same kind of knowledge about the typical causes of userspace software and distributed systems being slow to start. In my experience, for proprietary software, it's mostly because people inserted random calls to sleep()...
niklasd 7y ago
The link in the answer titled "state machines" is a bit misleading, since it directs to the Wikipedia entry about Finite-state machines. But most computers (the ones we are talking about here) are Turing complete rather than being a (computationally much more limited) finite-state machine.
- spacehome 7y ago
  I want to live in your world with its infinite memory.
- muthdra 7y ago
  https://en.wikipedia.org/wiki/State_machine https://en.wikipedia.org/wiki/State_machine
usernam33 7y ago
This reminds me of something I read about memristors. Once they get cheap and fast enough to be sold in gb or tb sticks they might replace ram and ssd's/hdd's for some computers. This would allow a computer to boot once (at the factory) and then just return to the state it was when powered on again.
MrQuincle 7y ago
The more optimization in boot times, the higher the maintenance burden. I think this can only be solved on an architectural level by introducing "specialization" in a "general" manner. In other words, have a supervising process monitor times and adjust the system to the local hardware and software demands. The adjustments to be good probably require some kind of learning mechanisms, which you also don't want to have in a kernel itself. Just my two cents.
Doubl 7y ago
Hibernate is my preferred option when going off the computer but Windows doesn't offer it out of the box and more. You have to tweak settings. Why is that I wonder?
- phendrenad2 7y ago
  My guess is the same reason modern UIs suck: too complex for the average non-technical user to handle. They probably got tons of support requests asking what the heck the difference between "sleep" and "hibernate" was, and that's a hard question to answer if the person asking has no idea what RAM is...
- tsimionescu 7y ago
  My understanding is that on Desktops, the default is for Sleep to do 'Hybrid Sleep' - prepare for a hibernate, but sleep instead; if you have a power failure while the computer is sleeping, you should see it waking from. The hibernate when you turn back on, instead of booting from scratch. I know that this was the case at some point when I checked during the Windows 8 years, I don't know if this is still true.
  - Doubl 7y ago
    Interesting, I'll investigate
mschuster91 7y ago
You can do warm boot images (Sony's Linux-based Alpha cameras do this, for example), but these have to be tailor-made for each model... feasible for a camera manufacturer, impossible for a Linux distribution. But I do wonder why WBI generation and automatic usage upon first boot isn't more common (or possible at all)...
- flowless 7y ago
  GoPro cameras run RTOS and one of the threads run Linux which is cold booted only once (or during an update) and stored for next fast hot boots - it was only used for providing WiFi and streaming functionality.
gregw2 7y ago
If computer makers put the OS in ROM memory rather than RAM and had a well defined way of overlaying the two so the ROM state could seem to be modified by writes to RAM, you could get instant boot. Early PCs worked that way like the Commodore64, right?
- unilynx 7y ago
  The Commodore didn't copy itself from ROM to RAM, but that was a trick you could do yourself to speed up BASIC execution - the RAM was faster than ROM
- deleted 7y ago
  [deleted]
swebs 7y ago
>When you turn on your computer, it instantly executes code in BIOS or UEFI boot manager. It doesn't take much time to execute BIOS or UEFI boot manager. It will initialize your hardware, scan your storage devices for operating system, and run the operating system. It is usually the operating system that requires much time for loading. Eh, it takes from 10-15 seconds on my computer from pressing the power button to getting to GRUB. After that, it's only another 10 seconds or so to boot Ubuntu.
- tsjq 7y ago
  > it's only another 10 seconds or so to boot Ubuntu. that's nice. is that on SSD?
  - swebs 7y ago
    Yeah, a Samsung 840.
steve76 7y ago
No, there are risks involved. In effect, it's making sure it doesn't Dell Laptop shards of "idealized transitor" into your cardiac or central nervous system. My dear friend. The world cares not for ONE death. The world cares very much for CANT DIE NO MATTER WHAT. Invincible Immortality Per Graphene. ... ... ... R I S E.
air7 7y ago
This is a good question, and the "answer" avoid it by essentially saying "it can't be zero." Why does boot time take ~10 seconds? CPUs run in GHz, meaning 10^9 operations per second. That means that booting takes around 10^10 operations. Why that order of magnitude and not any other? Obvious answer is "that's where the optimization efforts stopped", but could it be 10^9 or 10^8? Obviously booting time isn't just (or mostly) CPU, but the question extends to other peripherals: Harddrives access is in the 10^8 B/s range. RAM is 10^9 B/s. USB ~ 10^7 B/s. Wifi 10^6 B/s. etc. Why does booting, with all it's internal sub processes still take ~ 10^1 seconds and not any other OoM?
- Veedrac 7y ago
  10⁹ ops/s is an incredible underestimate; CPUs tend to have an IPC around 4, and at least two cores, even on mobile. Which means at 3GHz, you should have closer to 10¹¹ ops/s. The real question is not whether a computer can boot in a second, it's whether it can boot in a frame.
  - fulafel 7y ago
    Actual observed IPC tends to be 1 or less unless you are running well tuned computational workloads. And mostly software doesn't utilize multiple cores well.
    - Veedrac 7y ago
      Even ‘perf stat libreoffice ./somedocument.odt’ give an IPC of almost 2, and that's hardly a well-tuned computational workload. > And mostly software doesn't utilize multiple cores well. Most software sucks, that's the point of this whole conversation.
      - fulafel 7y ago
        Valid correction, seems I was out of date, let's say 2 or below today. (I got 1.3-1.7 with a few libreoffice startup & command-line conversion experiments). However during the boot process I think the IPC will be notably less, because there will be periods of waiting for disk IO and hardware initialization waits. To zoom out, there are two dimensions here - it's good for software to run at a good IPC, but even better to do the job with fewer instructions.
kerkeslager 7y ago
I remember when Ubuntu was first becoming popular. At the time, Windows boot times were long--I don't have timings, but my memory seems to say something like 5 minutes. And Intel processors were in the middle of their highest-energy-use period, so they ran hot, meaning you couldn't just leave your laptop on all the time. So reboot time was a significant part of my experience as a Windows user. When I first booted Ubuntu, the boot time was fast, something like a 1 minute, and later I tried Xubuntu which was closer to 30 seconds. This was an advertised advantage of Ubuntu, and it was a big part of why that was "the year of desktop Linux" (if only for me). In the following years, I noticed significant improvements both to boot times in Windows and to their "sleep"-type features. I suspect this was motivated at least in part by competition from Ubuntu.
- bonoboTP 7y ago
  > I suspect this was motivated at least in part by competition from Ubuntu. Ubuntu has such tiny market share that I strongly doubt this.
  - dannypgh 7y ago
    Ubuntu and Linux may have a small market share in the general population, but they enjoy a larger share among software developers. And we all know ("developers, developers, developers!") MS has chased that demographic.
  - kalleboo 7y ago
    It seems just as likely it was competition from the Mac, which also at one point during Steve's reign focused on boot time
jasonhansel 7y ago
The real answer: the cost (in developer time) of making computers that boot instantly is too high to justify the benefits.
- orbital-decay 7y ago
  Yes, but it's just one of the factors, and actually all major user-facing OSes do care about boot times. Other factors are the design by committee and platform fragmentation. Hardware manufacturers don't care about initialization times, and standard makers are issuing insanely complex specifications with lots of compatibility cruft and edge cases.
bane 7y ago
All of the answers here are missing something. In the old days, the OS was often on a ROM that was simply mapped into some unified memory location. Thus the system went from a state of "off" to "ready to go" pretty much immediately. There wasn't a need to copy the data from the ROM to RAM and then execute some stuff to get into an initialized mode. If you hunt around a bit for things like "atari 800 memory map" you can find diagrams showing how this all worked. In fact on some systems, you could selectively map certain things from ROM into the memory map to get more RAM if you wanted. Today, the move to put the OS onto disk, the memory hierarchy, and virtual memory eliminate this approach. You basically have to let the virtual memory system map things from disk into some page space, and often things need to be copied into RAM, work their way up the cache hierarchy and be executed somewhere in order to set the system into an initialized state. I've honestly forgotten nearly all of the details so maybe somebody else can provide a better explanation. So the reason computer can't boot instantly: 1) We have a complex memory system these days that prevent mapping the OS into the memory address space. 2) OS's aren't in ROM anymore. They sit on disk in a state different than when under operation. 3) Simple engineering willpower. Nobody wants to bother to figure it out because once the system is booted it doesn't really matter (with modern sleep modes and whatnot).
- Baeocystin 7y ago
  I am still waiting for the computing world to catch up to the instant-boot, straight-to-REPL joy that was my Commodore 128. I say that only partly tongue-in-cheek. The home machines in that era were right on the cusp; they were complex enough that you could do Genuinely Interesting Stuff with them, and simple enough that you could still hold the whole machine in your head. The instant feedback of REPL being the primary interface, and the almost zero-time cost of rebooting when an experiment didn't work out, made for a spectacular tool for self-learning.
- Dylan16807 7y ago
  Grabbing the kernel and login screen off of an SSD, then mapping the rest of what you need into virtual memory, is something that's easily accomplished in 100ms. If you design for 3-5 seconds of password typing that's enough time to grab gigabytes in the background. The complex memory system isn't the culprit here. It's one of the easiest parts to set up.
fulafel 7y ago
Trivia: some compuers have a single level memory store, so there are no separate disk and ram concepts from se PoV. I think as/400 and maybe Multics are like this. But i don't know if they boot instantly from whete they left off, probably not. It would be within relatively easy reach though.
- trn 7y ago
  For new install and first (cold) boot for a Multics system, the system is loaded from a Multics System Tape. As part of this process, the entire MST is loaded in Multics memory; Multics is partially started up to configure all of hardcore for the current hardware configuration; Multics then transfers back to BCE without shutdown. BCE captures this configured Multics hardcore memory image, and saves it to a file in the BCE disk partition. BCE then returns control to Multics hardcore, so it can continue system start-up. Subsequent (fast) boots from BCE boot the preconfigured Multics memory image, loading it from disk into memory, and transferring into the image, just as was done when the image was first saved.
vilhelm_s 7y ago
It could probably be faster if people cared to optimize it, e.g. some experiments to boot an embedded linux system to the console prompt in less than 1 second (https://fossforce.com/2017/01/linux-zero-boot-second/ https://fossforce.com/2017/01/linux-zero-boot-second/), or to the Qt Camera Preview app in 3 seconds (https://www.e-consystems.com/Articles/Product-Design/Linux-Boot-Time-Optimization-Techniques.asp https://www.e-consystems.com/Articles/Product-Design/Linux-B...) or to a Debian desktop in "5 seconds" (https://wiki.debian.org/BootProcessSpeedup#Tests_results_of_users https://wiki.debian.org/BootProcessSpeedup#Tests_results_of_...).
jokoon 7y ago
Further question would be: "If I saved all my work, why do I need to properly shut down my computer? Why does it take so long to shut down?"
lazyjones 7y ago
All this guessing and conjecture is pointless. Someone should simply measure what takes so long with the profiling tools available and post an analysis.
tbyehl 7y ago
What gets me is how long servers take to reach the bootloader from power on. Your average modern Dell/HP desktop or laptop is there within a second or two, Windows 10 and systemd-based Linux distros on SSD can be at the login prompt within 5 seconds total. I haven't touched a Mac in a long time but I'd bet they're no worse. But a typical server BIOS takes 3-5 minutes do its thing. If you're lucky you might be able to disable enough stuff to shave off a minute. Insanity.
- kalleboo 7y ago
  I bought an old 1/10 Gbit managed switch for $25 on an online auction to play around with, and was surprised just how long (minutes) a switch can take to boot.
  - tbyehl 7y ago
    A managed switch is basically an embedded server with super-slow storage. If it's of a certain age you might pop the cover and find a CompactFlash card. I run my most critical piece of home infrastructure (PiHole, of course) bare-metal on an ancient NUC-like thing with a $20 SSD because it boots and is responding to network requests in like 6 seconds.
cookingrobot 7y ago
Here's a proposal.. Don't do any network stuff during boot, and don't let it depend on anything super volatile like user files. Then store the boot memory state as an image (like a hyberfile). Whenever a bigger change happens to the system that will affect the boot state, like installing a new driver, or an app that has any kind of background service, recreate a new boot image. But do it right away when the new app is installed, don't wait for the next boot, or shutdown (which is annoying), just do it in a virtual machine right away as part of the app/driver install. Installing impactful apps will take longer, but that can happen in the background and is not too disruptive, and doesn't happen very often anyway.
bin0 7y ago
Let me take a moment to vent on the garbage that is the dell UEFI firmware. I have an excellent, new machine, an XPS 15 9570. According to systemd-analyze, it took eight seconds to get past firmware, corroborated by my observations. There is flat-out no reason why it ought to be so slow. Dell makes the absolute worst BIOS.

146 points by anon35 7y ago

More interesting question to me is why the hell some firmware boots take so long now. I know laptops from years ago much, much faster than what I have now, which is otherwise much faster than them. And the firmware initialization times for some servers I've seen seem completely obscene (on the order of minutes).

aardvarklegend 7y ago
Surprisingly power is a huge factor. Spinning up 48/96 drives on boot can surge beyond what power supplies could handle, so things supported staggered spin ups. This allowed huge banks of drives to start without blowing a power supply, but you don’t know how many drives or if staggered spin up is enabled until it times out. This was a huge boot delay for servers.
- mehrdadn 7y ago
  That's interesting to note, but I'm just talking about computers with 1 drive connected to them. Both for the servers and the laptops. In fact the older (faster) laptop had both a DVD and an HDD, whereas the newer one just has an SSD...
gingabriska 7y ago
Today we have to make things hack proof, noob proof and lots of proofing adds more complexity, cost and lowers speed.
- mehrdadn 7y ago
  I don't think this is it. I haven't tried with many machines but I don't think current machines are all generally slow with firmware, just some of them. The part that baffles me is that the slowness is on the faster ones.
scarejunba 7y ago
Probably because no one turns anything off anymore so the selection pressure is gone.
- gambiting 7y ago
  So I'm not so sure about that. When I complained recently about sleep issues on my windows 10 desktop I was met with an overwhelming "but....why are you sleeping your desktop? Just switch it off like a normal person?".
  - distances 7y ago
    Indeed. I've no idea if sleep works on my desktop. I've never tried.

verisimilitudes 7y ago

Windows is a bloated mess, so it's obvious there. As for anything POSIX, it's because UNIX is shitware; it took a long time to boot decades ago and it takes a long time to boot now, because more garbage has been piled on top. It's possible for a good operating system to boot in less than a second, however. People have simply been conditioned to accept this unacceptable state of affairs, no different than a TV that takes ten seconds to become usable for no reason other than the manufacturer was lazy.

johnchristopher 7y ago
While I don't agree with everything you wrote I would like to add android boot time to the list.
galfarragem 7y ago
I still remember the day I got a new TV (despite old CRT working) for my parents and see their faces the first time time we turned it on. Now they are used but at the beggining the boot time was difficult to grasp: it used to be negligible with the obsolete tech..
- FrancoisBosun 7y ago
  There is now a boot time for my kitchen mixer… about 2-3 seconds. It’s horrible and I always forget.
  - sverige 7y ago
    Honestly, "smart" appliances are the worst idea since . . . I can't actually think of a worse idea.
    - brokenmachine 7y ago
      Recently I got an email ad for a "smart" kettle with an app that you can remotely turn the kettle on, or schedule a time for it to turn on...
- 7y ago

mojuba 7y ago

A bigger question for me is, why can't monitors boot instantly? So annoying that a monitor that went to sleep can sometimes take 10-20 seconds longer to wake up than the computer it is attached to.

quickthrower2 7y ago
But my 5” touchscreen monitor can...
gruez 7y ago
If it's really 10-20s, I'm guessing it's because it's because it's cycling through the various input sources looking for a signal.
- ebg13 7y ago
  But it could just look at all of the input sources at the same time. And anyway, these are solid state electronics, not hamsters and flywheels. Taking seconds to send "give me electrons" and for the other side to say "here are some electrons" is bonkers.
  - jamesissac 7y ago
    Being able to observe all inputs sources at the same time requires extra hardware(more utilisation of the FPGA resources), considering only one input is connected to the display at a time. So it's probable that the check is sequential.
    - lazyjones 7y ago
      I know you’re just guessing, but if that’s what happens, why don’t they just default to the last source used and start the cycling only if nothing is detected there?
    - ebg13 7y ago
      "More" isn't a meaningful qualifier without a quantifier. I'm not convinced that it would take more than $0.01 worth of resource. I could even see doing it in a purely analog fashion with an extremely basic component like a mosfet. If a pin goes high because the computer responded to your request to send electrons, it sets the corresponding channel. > So it's probable that the check is sequential. It's a user unfriendly design for the process to be "send request, wait 5 seconds, send request on next channel, wait 5 seconds, send request on next channel, ..." when it could instead be sending requests across all channels rapidly and then that getting a response on a particular channel _activates_ that channel by analogue means.

imtringued 7y ago

Because everything takes non zero time. If a state transition from turned off to booted takes no time then doesn't that mean there is no state transition at all? The only way for it to take zero time for a computer to boot is if it is already booted or there is no difference between an unbooted computer and a booted one. How much time does it take for a circle to become round? None at all. It happened instantly.

jarfil 7y ago
It also takes hours to compile everything from scratch, but we don't see computers taking hours to boot, do we? Most of the process "from initial state" is cached, and there is little reason to not keep the trend. Booting, as in detecting and initializing the hardware, including the RAM, should only be needed when hardware is changed, and even then it should be possible to cache the state of any unchanged parts.

Bakary 7y ago

A silver lining of long boot times is that you can contemplate what you are about to use the computer for and catch yourself in the middle of a habit loop.

tsjq 7y ago
haha. that's a good one.
vendiddy 7y ago
Can't tell if you're joking but actually like this idea.
kalleboo 7y ago
I bet adding a 15 second wakeup time to my smartphone would abort about 75% of my social media usage

argimenes 7y ago

When I was in high school their Amiga would cold boot into a GUI within 3 seconds. It was the same for the Acorn Archimedes in the UK. These computers had the entire GUI OS burnt into the ROM. After that I remember the shock or getting a 386 and waiting minutes for Windows 95 to load. It was like the future had died and was buried by a conspiracy of silence in the industry.

unnouinceput 7y ago
386 and W95? Not a good combination. By the time W95 was out on the market P5 was the latest and greatest and a 486 was the low budget one. You might want to reconsider those memories. As for loading times it all boiled down on how many check-up you wanted or not in your BIOS. As a rule I've always did memory check by BIOS only one time when buying/putting together a new PC and after that I've check it off in BIOS, halving the time it need it to boot. It was perfectly easy to have a 3 seconds BIOS time, sometime was even a nuisance to make it that short because you'd had to be fast to press Del (or whatever the BIOS key was) if you wanted to go to BIOS instead.
- dmead 7y ago
  you're conflating a bunch of stuff here.
- avian 7y ago
  > By the time W95 was out on the market P5 was the latest and greatest and a 486 was the low budget one. You might want to reconsider those memories. Maybe the 486 was the low end of what you could buy at the time, but not everyone bought a new computer. My parents upgraded their 386 from Windows 3.1 to 95. It was slow, but usable.
  - unnouinceput 7y ago
    In 3rd year at Uni, in good old '96 I had a P5 with W95 in my dorm room. Granted, not mine, but the friend and colleague who had it was not some rich parents kid, just middle class. We played HOMM2 on it all day long, much to his gf dismay.

basicplus2 7y ago

My old valve televisions are up and running long before ANY smart tv, AND its quicker to change channels

thrownhwn 7y ago

Has someone explored the area of writing software that spits out resume from disk images?

amelius 7y ago
You mean hibernation? That exists for a long time now, but is technically not booting.
- jarfil 7y ago
  Alternatively, booting is just an inefficient "resume from disk", using a generic initial state instead of one adapted to the device.

CGamesPlay 7y ago

A lot of these answers are why computers don’t boot instantly but none really talk about why they can’t. The accepted answer talks about it on a physical/mechanical level but eschews practicality: what can’t computers boot arbitrarily quickly?

enneff 7y ago
They can. But the more software you need to initialise the slower it is. And modern machines run a lot of software.
- maxheadroom 7y ago
  >...the more software you need to initialise the slower it is... Of course, part of that initialisation is self-tests, harkening back to the O.G. POST[0] days. [0] - https://en.wikipedia.org/wiki/Power-on_self-test https://en.wikipedia.org/wiki/Power-on_self-test
- adsche 7y ago
  But then the questions are, why does it need to initialize? Why doesn't it start in an initialized state, what factors make it impossible to determine that initialized state beforehand and storing it? How close can we get?
  - silon42 7y ago
    The fact that reboots happen mostly when software (kernels, system) is upgraded is part of it. It's simplest and most reliable to initialize the system from clean state (I've often had an idea it would be best to reinstall Windows+software for each reboot).
    - adsche 7y ago
      Yes, but do you have an idea why that is, why is it so much more reliable to initalize every time than to generate an initialized configuration and reuse that? Developer errors? Not enough testing?

ohiovr 7y ago

My POST sequence takes longer than the boot process so no matter how blazing fast my drives are it still takes a long time to get to the boot loader.

faissaloo 7y ago
Nail on the head, UEFI/BIOS is increasingly the bottleneck for startup speeds nowadays

kzrdude 7y ago

I'm pretty happy with boot times, the longest wait is the boot loader and inputting the password. (Linux with full disk encryption).

thecopy 7y ago

Because of state.

sansnomme 7y ago

I have a question too: why does radios take so long to start up and acquire a signal? Same for other I/O devices similar to radios，on the embedded side you have keep on polling until finally it acquires the signal.

simcop2387 7y ago
One common thing is that the radio needs time for it's clock source to stabilize. To make them cheaper they usually use things like phase locked loops to take a lower frequency clock and multiply it up to the clock they need. This can take tens to thousands of milliseconds to bnot be bouncing around when first configuring the loop. And with modern radios, these loops get programed at run-time from the firmware because they need to be at a large range of frequencies. During this startup you can't transmit anything, because you'll transmit with another signal (the clock jitter) mixed in which adds noise, at best, and possibly even at a completely incorrect frequency which will result in fines or possibly jail time. The safe route is just to wait instead. Receivers work similarly, using PLLs to downmix the signal they want, generally, and while they can begin trying to receive while waiting on it to stabilize, it's usually pointless because you'll just be getting unintelligible garbage from the noise or wrong frequency.

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.

kstenerud 7y ago

There are a number of reasons: 1. Hardware Hardware is a big problem for boot times. Most hardware is poorly standardized, or not standardized at all, or doesn't even follow the standards, or tries to be backwards compatible with older hardware, or is just plain buggy. This means that the initialization code has to poll and retry and work around a whole bunch of things just in case the hardware happens to be slow in responding or gives a weird response. This is the main reason why POST is so godawful slow, and why the initial linux boot sequence takes so long. Apple hardware can boot quicker because they control what hardware is in the machine and can optimize their initialization code for it. 2. Software The operating system stack is HUGE. There's a LOT of state that needs to be initialized, and most of it is not very efficient (we tend to optimize the runtime operation vs the startup operation of a software package). You absolutely could cut the software component of an OS boot sequence by an order of magnitude, but the development costs would be massive, and the gains pathetic in terms of the work-over-time the machine will do over its lifespan. 3. Protocols A large number of the protocols we use for inter-process and inter-device communication have poorly designed latency characteristics. Either they are too chatty (requiring multiple messages back and forth to do a task), or have ill-defined timeouts (requiring clients to wait longer than they should), or ambiguous states, or some poorly built implementation has become the de facto standard. This is an area I'm personally tackling. 4. Formats We use a number of formats for the wrong kinds of things. Appending to a tgz file, for example, has horrendous time implications, especially as the archive size grows.

catern 7y ago
This is a really good summary of some of the main reasons - more interesting detail than many of the other comments here. Now what would really be interesting is if we had the same kind of knowledge about the typical causes of userspace software and distributed systems being slow to start. In my experience, for proprietary software, it's mostly because people inserted random calls to sleep()...

niklasd 7y ago

The link in the answer titled "state machines" is a bit misleading, since it directs to the Wikipedia entry about Finite-state machines. But most computers (the ones we are talking about here) are Turing complete rather than being a (computationally much more limited) finite-state machine.

spacehome 7y ago
I want to live in your world with its infinite memory.
muthdra 7y ago
https://en.wikipedia.org/wiki/State_machine https://en.wikipedia.org/wiki/State_machine

usernam33 7y ago

This reminds me of something I read about memristors. Once they get cheap and fast enough to be sold in gb or tb sticks they might replace ram and ssd's/hdd's for some computers. This would allow a computer to boot once (at the factory) and then just return to the state it was when powered on again.

MrQuincle 7y ago

The more optimization in boot times, the higher the maintenance burden. I think this can only be solved on an architectural level by introducing "specialization" in a "general" manner. In other words, have a supervising process monitor times and adjust the system to the local hardware and software demands. The adjustments to be good probably require some kind of learning mechanisms, which you also don't want to have in a kernel itself. Just my two cents.

Doubl 7y ago

Hibernate is my preferred option when going off the computer but Windows doesn't offer it out of the box and more. You have to tweak settings. Why is that I wonder?

phendrenad2 7y ago
My guess is the same reason modern UIs suck: too complex for the average non-technical user to handle. They probably got tons of support requests asking what the heck the difference between "sleep" and "hibernate" was, and that's a hard question to answer if the person asking has no idea what RAM is...
tsimionescu 7y ago
My understanding is that on Desktops, the default is for Sleep to do 'Hybrid Sleep' - prepare for a hibernate, but sleep instead; if you have a power failure while the computer is sleeping, you should see it waking from. The hibernate when you turn back on, instead of booting from scratch. I know that this was the case at some point when I checked during the Windows 8 years, I don't know if this is still true.
- Doubl 7y ago
  Interesting, I'll investigate

mschuster91 7y ago

You can do warm boot images (Sony's Linux-based Alpha cameras do this, for example), but these have to be tailor-made for each model... feasible for a camera manufacturer, impossible for a Linux distribution. But I do wonder why WBI generation and automatic usage upon first boot isn't more common (or possible at all)...

flowless 7y ago
GoPro cameras run RTOS and one of the threads run Linux which is cold booted only once (or during an update) and stored for next fast hot boots - it was only used for providing WiFi and streaming functionality.

gregw2 7y ago

If computer makers put the OS in ROM memory rather than RAM and had a well defined way of overlaying the two so the ROM state could seem to be modified by writes to RAM, you could get instant boot. Early PCs worked that way like the Commodore64, right?

unilynx 7y ago
The Commodore didn't copy itself from ROM to RAM, but that was a trick you could do yourself to speed up BASIC execution - the RAM was faster than ROM
deleted 7y ago
[deleted]

swebs 7y ago

>When you turn on your computer, it instantly executes code in BIOS or UEFI boot manager. It doesn't take much time to execute BIOS or UEFI boot manager. It will initialize your hardware, scan your storage devices for operating system, and run the operating system. It is usually the operating system that requires much time for loading. Eh, it takes from 10-15 seconds on my computer from pressing the power button to getting to GRUB. After that, it's only another 10 seconds or so to boot Ubuntu.

tsjq 7y ago
> it's only another 10 seconds or so to boot Ubuntu. that's nice. is that on SSD?
- swebs 7y ago
  Yeah, a Samsung 840.

steve76 7y ago

No, there are risks involved. In effect, it's making sure it doesn't Dell Laptop shards of "idealized transitor" into your cardiac or central nervous system. My dear friend. The world cares not for ONE death. The world cares very much for CANT DIE NO MATTER WHAT. Invincible Immortality Per Graphene. ... ... ... R I S E.

air7 7y ago

This is a good question, and the "answer" avoid it by essentially saying "it can't be zero." Why does boot time take ~10 seconds? CPUs run in GHz, meaning 10^9 operations per second. That means that booting takes around 10^10 operations. Why that order of magnitude and not any other? Obvious answer is "that's where the optimization efforts stopped", but could it be 10^9 or 10^8? Obviously booting time isn't just (or mostly) CPU, but the question extends to other peripherals: Harddrives access is in the 10^8 B/s range. RAM is 10^9 B/s. USB ~ 10^7 B/s. Wifi 10^6 B/s. etc. Why does booting, with all it's internal sub processes still take ~ 10^1 seconds and not any other OoM?

Veedrac 7y ago
10⁹ ops/s is an incredible underestimate; CPUs tend to have an IPC around 4, and at least two cores, even on mobile. Which means at 3GHz, you should have closer to 10¹¹ ops/s. The real question is not whether a computer can boot in a second, it's whether it can boot in a frame.
- fulafel 7y ago
  Actual observed IPC tends to be 1 or less unless you are running well tuned computational workloads. And mostly software doesn't utilize multiple cores well.
  - Veedrac 7y ago
    Even ‘perf stat libreoffice ./somedocument.odt’ give an IPC of almost 2, and that's hardly a well-tuned computational workload. > And mostly software doesn't utilize multiple cores well. Most software sucks, that's the point of this whole conversation.
    - fulafel 7y ago
      Valid correction, seems I was out of date, let's say 2 or below today. (I got 1.3-1.7 with a few libreoffice startup & command-line conversion experiments). However during the boot process I think the IPC will be notably less, because there will be periods of waiting for disk IO and hardware initialization waits. To zoom out, there are two dimensions here - it's good for software to run at a good IPC, but even better to do the job with fewer instructions.

kerkeslager 7y ago

I remember when Ubuntu was first becoming popular. At the time, Windows boot times were long--I don't have timings, but my memory seems to say something like 5 minutes. And Intel processors were in the middle of their highest-energy-use period, so they ran hot, meaning you couldn't just leave your laptop on all the time. So reboot time was a significant part of my experience as a Windows user. When I first booted Ubuntu, the boot time was fast, something like a 1 minute, and later I tried Xubuntu which was closer to 30 seconds. This was an advertised advantage of Ubuntu, and it was a big part of why that was "the year of desktop Linux" (if only for me). In the following years, I noticed significant improvements both to boot times in Windows and to their "sleep"-type features. I suspect this was motivated at least in part by competition from Ubuntu.

bonoboTP 7y ago
> I suspect this was motivated at least in part by competition from Ubuntu. Ubuntu has such tiny market share that I strongly doubt this.
- dannypgh 7y ago
  Ubuntu and Linux may have a small market share in the general population, but they enjoy a larger share among software developers. And we all know ("developers, developers, developers!") MS has chased that demographic.
- kalleboo 7y ago
  It seems just as likely it was competition from the Mac, which also at one point during Steve's reign focused on boot time

jasonhansel 7y ago

The real answer: the cost (in developer time) of making computers that boot instantly is too high to justify the benefits.

orbital-decay 7y ago
Yes, but it's just one of the factors, and actually all major user-facing OSes do care about boot times. Other factors are the design by committee and platform fragmentation. Hardware manufacturers don't care about initialization times, and standard makers are issuing insanely complex specifications with lots of compatibility cruft and edge cases.

bane 7y ago

All of the answers here are missing something. In the old days, the OS was often on a ROM that was simply mapped into some unified memory location. Thus the system went from a state of "off" to "ready to go" pretty much immediately. There wasn't a need to copy the data from the ROM to RAM and then execute some stuff to get into an initialized mode. If you hunt around a bit for things like "atari 800 memory map" you can find diagrams showing how this all worked. In fact on some systems, you could selectively map certain things from ROM into the memory map to get more RAM if you wanted. Today, the move to put the OS onto disk, the memory hierarchy, and virtual memory eliminate this approach. You basically have to let the virtual memory system map things from disk into some page space, and often things need to be copied into RAM, work their way up the cache hierarchy and be executed somewhere in order to set the system into an initialized state. I've honestly forgotten nearly all of the details so maybe somebody else can provide a better explanation. So the reason computer can't boot instantly: 1) We have a complex memory system these days that prevent mapping the OS into the memory address space. 2) OS's aren't in ROM anymore. They sit on disk in a state different than when under operation. 3) Simple engineering willpower. Nobody wants to bother to figure it out because once the system is booted it doesn't really matter (with modern sleep modes and whatnot).

Baeocystin 7y ago
I am still waiting for the computing world to catch up to the instant-boot, straight-to-REPL joy that was my Commodore 128. I say that only partly tongue-in-cheek. The home machines in that era were right on the cusp; they were complex enough that you could do Genuinely Interesting Stuff with them, and simple enough that you could still hold the whole machine in your head. The instant feedback of REPL being the primary interface, and the almost zero-time cost of rebooting when an experiment didn't work out, made for a spectacular tool for self-learning.
Dylan16807 7y ago
Grabbing the kernel and login screen off of an SSD, then mapping the rest of what you need into virtual memory, is something that's easily accomplished in 100ms. If you design for 3-5 seconds of password typing that's enough time to grab gigabytes in the background. The complex memory system isn't the culprit here. It's one of the easiest parts to set up.

fulafel 7y ago

Trivia: some compuers have a single level memory store, so there are no separate disk and ram concepts from se PoV. I think as/400 and maybe Multics are like this. But i don't know if they boot instantly from whete they left off, probably not. It would be within relatively easy reach though.

trn 7y ago
For new install and first (cold) boot for a Multics system, the system is loaded from a Multics System Tape. As part of this process, the entire MST is loaded in Multics memory; Multics is partially started up to configure all of hardcore for the current hardware configuration; Multics then transfers back to BCE without shutdown. BCE captures this configured Multics hardcore memory image, and saves it to a file in the BCE disk partition. BCE then returns control to Multics hardcore, so it can continue system start-up. Subsequent (fast) boots from BCE boot the preconfigured Multics memory image, loading it from disk into memory, and transferring into the image, just as was done when the image was first saved.

vilhelm_s 7y ago

It could probably be faster if people cared to optimize it, e.g. some experiments to boot an embedded linux system to the console prompt in less than 1 second (https://fossforce.com/2017/01/linux-zero-boot-second/ https://fossforce.com/2017/01/linux-zero-boot-second/), or to the Qt Camera Preview app in 3 seconds (https://www.e-consystems.com/Articles/Product-Design/Linux-Boot-Time-Optimization-Techniques.asp https://www.e-consystems.com/Articles/Product-Design/Linux-B...) or to a Debian desktop in "5 seconds" (https://wiki.debian.org/BootProcessSpeedup#Tests_results_of_users https://wiki.debian.org/BootProcessSpeedup#Tests_results_of_...).

jokoon 7y ago

Further question would be: "If I saved all my work, why do I need to properly shut down my computer? Why does it take so long to shut down?"

lazyjones 7y ago

All this guessing and conjecture is pointless. Someone should simply measure what takes so long with the profiling tools available and post an analysis.

tbyehl 7y ago

What gets me is how long servers take to reach the bootloader from power on. Your average modern Dell/HP desktop or laptop is there within a second or two, Windows 10 and systemd-based Linux distros on SSD can be at the login prompt within 5 seconds total. I haven't touched a Mac in a long time but I'd bet they're no worse. But a typical server BIOS takes 3-5 minutes do its thing. If you're lucky you might be able to disable enough stuff to shave off a minute. Insanity.

kalleboo 7y ago
I bought an old 1/10 Gbit managed switch for $25 on an online auction to play around with, and was surprised just how long (minutes) a switch can take to boot.
- tbyehl 7y ago
  A managed switch is basically an embedded server with super-slow storage. If it's of a certain age you might pop the cover and find a CompactFlash card. I run my most critical piece of home infrastructure (PiHole, of course) bare-metal on an ancient NUC-like thing with a $20 SSD because it boots and is responding to network requests in like 6 seconds.

cookingrobot 7y ago

Here's a proposal.. Don't do any network stuff during boot, and don't let it depend on anything super volatile like user files. Then store the boot memory state as an image (like a hyberfile). Whenever a bigger change happens to the system that will affect the boot state, like installing a new driver, or an app that has any kind of background service, recreate a new boot image. But do it right away when the new app is installed, don't wait for the next boot, or shutdown (which is annoying), just do it in a virtual machine right away as part of the app/driver install. Installing impactful apps will take longer, but that can happen in the background and is not too disruptive, and doesn't happen very often anyway.

bin0 7y ago

Let me take a moment to vent on the garbage that is the dell UEFI firmware. I have an excellent, new machine, an XPS 15 9570. According to systemd-analyze, it took eight seconds to get past firmware, corroborated by my observations. There is flat-out no reason why it ought to be so slow. Dell makes the absolute worst BIOS.