topic Re: Facebook's problem in XPERIA archive

Facebook's problem

Marco1987 — Sun, 06 Jul 2014 21:11:04 GMT

When i'm in facebook's app, not always but once a week, my phone freeze and then restarts itself... It's a software or hardware problem? It can be solved?thanks

Re: Facebook's problem

_alexdon_ — Sun, 06 Jul 2014 21:15:56 GMT

Try settings-apps-all-facebook,force stop and clear data.Restart.

Re: Facebook's problem

toothpaste — Sun, 06 Jul 2014 21:42:27 GMT

you can't really fix it

facebook does some not-so-nice things with the dalvik vm at runtime

read here

https://www.facebook.com/notes/facebook-engineering/under-the-hood-dalvik-patch-for-facebook-for-android/10151345597798920

and here

http://jaxenter.com/facebook-s-completely-insane-dalvik-hack-46376.html

Re: Facebook's problem

Sam — Mon, 07 Jul 2014 04:15:28 GMT

Always make sure you have the latest version of the Facebook application as well as they tend to release updates very frequently.

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Re: Facebook's problem

toothpaste — Mon, 07 Jul 2014 04:54:14 GMT

is it acceptable though that the phone freezes/restarts because of an app?

the entire system brought down due to a program?

it's like we're twenty years ago back to the windows 95 era.

Re: Facebook's problem

Sam — Mon, 07 Jul 2014 04:58:54 GMT

@toothpaste - This can happen with anything from top end smartphones to a high end gaming PC. It is unfortunate but given the complexity and level of variations in the different hardware one app must be made for this kind of thing can happen, however it is certainly not common.

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Re: Facebook's problem

toothpaste — Mon, 07 Jul 2014 06:22:36 GMT

let's not get there.

i have, currently, two desktops, two laptops and a netbook. I've had many others through the recent years.

Ever since windows XP this has never happened with the frequency that it happens on android devices. I do not remember the last time it has happened to me, at all. I remember both my netbook and desktop spectacularly crashing, but that was due to OCZ SSDs.

No sam, it doesn't happen and even if it did, it still wouldn't be an excuse.

for a desktop i might excuse it... i can still all sorts of hardware in it, chinese knockoff webcams with crappy """wdm""" drivers or beta gpu drivers... Yeah, the drivers since they are running in kernel-space, are a big problem

but for an embedded device with known, UNswappable, hardware with very specific drivers (i can't go in there and install whatever hardware or drivers i want, can i?), that we NEED to be relatively high availability?

nope, sorry, inexcusable. Seriously. This is not up for debate.

Re: Facebook's problem

toothpaste — Mon, 07 Jul 2014 06:39:35 GMT

> level of variations in the different hardware one app must be made for this kind of thing can happen

ouch.

that's wrong on so many levels it commands its own reply

first off. it's a program. not a device driver. a device driver malfunctioning may bring a system down, because the kernel can't isolate kernel-space programs (drivers). That is what happens when on a windows machine you see a BSOD. When a normal program (running in user-space) fails, you get the usual "this program, illegal operation, blah" window aaaand that's it. The OS gives the boot to the program and that's it.

second. the whole idea behind the dalvik vm is that the hardware doesn't matter, from the perspective of the coder. No matter what is an android device using (let's ignore for the moment that the only existing and supported architecture for android devices is the armv7, which pretty much renders the existance of a VM-based solution like dalvik completely unnecessary) the coder needs only worry about the 'abstraction' given to him. Now, if the whole idea is badly engineered and the programmer still needs to worry about hardware-specifics, then it's a failure, right? Because you get the bad things from BOTH worlds. You get the inefficiency and performance loss from the VM abstraction and you get the complexity and bugs from needing to cover each hardware case differently.

third. The OS, via its API, is supposed to be the interface between a program and the hardware. It offers an abstraction of the hardware (device) to the software (programs). This is done to solve the problem of "so many different hardware out there, how am i going to code my app for each different device?". Also, it isolates the 'dangerous' code (code that runs in kernel-space) from the normal programs. So the device driver is written by the company that makes the hardware and makes **bleep** sure to be bulletproof because it is going to run in kernel-space (otherwise it can't talk to the hardware). The program is written by the programmer and runs in user-space, since it doesn't access the hardware directly.

so, in short: there is no variation, facebook doesn't access the hardware, doesn't need to and shouldn't even be allowed to.

your turn.

as a postscript: when a program crashes and the system reboots, it's not the program's fault. It's the OPERATING SYSTEM'S FAULT. Because the operating system is responsible for keeping each program safe from each other and the system safe from the software.

edit: before a cs student goes for the jugular, yes i have simplified some things i am not writing a textbook here.

Re: Facebook's problem

Marco1987 — Mon, 14 Jul 2014 12:24:48 GMT

@toothpaste are you teaching at M.I.T.? Ahah Lol
Thanks, now its seems fixed the problem