yashsingh1/xdaforums huggingface dataset:
[Windows Phone 7 Development and Hacking] Briefcase:
No reason to do that, because it will not work. Only way of IU a lumia is if you have the qualcomm bootloader. Only a handful of lumia 800's have this.

MONITOR THIS THREAD IF YOU WANT TO STAY IN TOUCH
[Windows Phone 7 Development and Hacking] GoodDayToDie:
Read the thread, at least the last few posts, please.

A) This app is *antique* and uses device-specific functionality that doesn't exist on the Lumia. It wouldn't work for you at all.

B) This app is from before the interop-lock (which was added in Mango). To even install it on a modern phone, you'd need to interop-unlock the phone first.

C) If the phone is already interop-unlocked, that means the 10-app limit has already been raised to over 300 (that's all interop-unlock is). If you can install this app, then there's no reason to do so.

EDIT: The above is for @neelgangrade, not @briefcase. Simultaneous posts!
[Windows Phone 7 Development and Hacking] neelgangrade:
thanks guys

thanks guys for quick reply ..!! i received ma FREE nokia lumia from the micro* .. for devlopment , but cant side load more apps !

stuck here :(

i ll ask them to send me two more wp7 phone for testing or software to unlock the side loading :D thanks
[Windows Phone 7 Development and Hacking] shb66:
can u please upload the file to some other hosting site, the captcha is not working on this french site, thanks
[Fascinate Android Development] RacerXFD:
So this is a development idea...

I thought about this the other day and realized that under volting could be causing my battery to die quickly...

Here's why.

V = I * R

Where v = volts, I = amps, R = ohms.

P = V * I

Where P = (power)watts

I know some of you are going to think that this doesn't belong in development, but here me out here.

So if the processor uses 1.5 Watts and we decrease the voltage, this means that the processor needs to increase current to maintain that power. This equates to reduced battery life.

I'm just suggesting that undervolting may be causing the low battery life. If you know better feel free to tell me I'm wrong, but please explain the mechanics of what is going on not just your theory.
[Fascinate Android Development] Relaxasaurus:
This question is over my head so I'll refrain from speculating directly on your theory. But real-world results with my undervolted Stupidfast 1.54 kernel gives me much better battery life than stock. Yes, this may be due also to the unbloated-ness as well so I'm not 100% certain the undervolting is the main help here
[Fascinate Android Development] agsded:
Well....I dunno how this applies to CPUs but.... I used to be a car audio installer/buff and when we noticed voltage sagging to an amplifier, the amplifier would compensate by pulling more amperage at the lower voltage. It never seemed to make much different to the batteries, but it did make the amps run much hotter...so....

Again, not sure if it would tie in, but....
[Fascinate Android Development] iTz Nicholas72:
Hmm I've never thought about that. From my RC knowledge the most efficient set ups are the ones that use high voltage but low amps.

I may have to try a OV kernel and see if I notice a difference...

Sent from my Samsung Fascinate running BH3.0, DL09, 125mv undervolt Voodoo5 using SwiftKey and Tapatalk
[Fascinate Android Development] soba49:
As a disclaimer, I have not performed any formal reading on this topic, these are just my idle ramblings.

My contention has been that you only enjoy the benefits of a UV kernel if you are a certain type of user.

If you are performing CPU intensive tasks, you reap the most benefit from the UV kernel because it needs less power to run at 1 GHz (or whatever the maximum clock speed is set to for that kernel).

If you spend alot of time idling, for instance reading interspersed by web requests, you are spending most of your time at the minimum clock speed. With the stock kernel, that is set to 0.1 GHz. With a UV kernel, the minimum clock needs to be set to something higher to keep the CPU running. You may be able to estimate what this speed needs to be based on the fundamental power calculations in the OP.

The governor quickly changes your clock speed based on your current usage & requirements. To make optimal use of the CPU governor, it should have access to the broadest possible range of speeds (without going higher than is useful/safe). Unfortunately, undervolting a kernel sacrifices some of the lower end of that range. Therefore, many users see much improved battery life, while others (like me) experience noticeably diminished overall performance from UV kernels.

Swyped w/ XDA App. When in doubt, mumble.
[Fascinate Android Development] FacundoL:
P=V*I

The processor does not draw a constant power, but it does have a minimum. The point of undervolting is bringing the power consumption to that minimum within the phones physical environment and user expectations of functionality.

So...

You are right.

However, processor frequency is dependant on current. Thus if you are undervolting to save battery life then you will need to keep your frequency the same or lower to notice a difference. If you are overclocking (increasing current) and undervolting then your P stays the same so the user ends up feeling the battery life to be the same or worse.

Facundo
[Fascinate Android Development] cckeeler:
Are there any standard or over volt kernels available so we can test this theory? It seems as though all the kernels available are UV.
[Fascinate Android Development] adrynalyne:
would you like a standard voltage kernel to test?
[Fascinate Android Development] CNemo7539:
Personally I see worse battery life on UV kernel. My usage mostly equals to dumb phone, with email sync and moderate web browsing.

I would change formula to I = V/R, which will read as current is directly proportional to voltage and inversely proportional to resistance. That makes obvious that reducing voltage we decrease current. However one point to note here is that this law is for PASSIVE conductor, which is obviously not our case. I would not speculate further, because we do not know what king of power conversion happens. It might simply turn out that conversion is not efficient at lower voltages. Google desktop power block certifications/efficiency to see whet I mean.
[Fascinate Android Development] adrynalyne:
I compiled some kernels so you folks can play with it. I SERIOUSLY doubt you will get better life with my stock voltage vs. undervolt, but give her a shot.

Undervolted

Voodoo

http://adrynalyne.us/files/kernels/adryn_test2_0116_fascinate_voodoo5.zip

Nonvoodoo

http://adrynalyne.us/files/kernels/adryn_test2_0116_fascinate_novoodooo.zip

Standard voltage

Voodoo

http://adrynalyne.us/files/kernels/adryn_sv_0116_fascinate_voodoo5.zip

Nonvoodoo

http://adrynalyne.us/files/kernels/adryn_sv_0116_fascinate_novoodoo.zip
[Fascinate Android Development] iTz Nicholas72:
I'm giving the SV Voodoo kernel a try right now.

Sent from my Samsung Fascinate running BH3.0, DL09, and Voodoo5 using SwiftKey and Tapatalk
[Fascinate Android Development] RacerXFD:
I thought about this as I thought about power lines. They use super high voltages to reduce the amount of power loss through the lines.

Anyways, sounds good, I'll test it out. I'd have to get a baseline. I guess I'll charge my phone right now and test out the regular voltage.

I'll let you guys know tomorrow the differences tomorrow.
[Fascinate Android Development] deaffob:
In all honesty, I don't ever feel that I get more juice out of unvervolt kernels and I've been using all kinds of kernels since the release of MT3G.
[Fascinate Android Development] soba49:
Thanks for the standard voltage kernel!

I do appreciate you efforts in continually optimizing these, having a baseline to compare to just makes it all the more wonderful.

I will give the SV (standard voltage) a day or so of testing and then compare the UV against to make the test fair. With ten minutes of use ^^, it is already a great contender for my daily driver. I had gone back to 11/29 from 12/30. 11/29 was a terrible pairing with DL09; my GPS was unusable.

$ busybox md5sum ad*.zip

aea1047f3b2d33e759064d47cc8cac27 adryn_sv_0116_fascinate_novoodoo.zip

Works great!

Swyped w/ XDA App. When in doubt, mumble.
[Fascinate Android Development] CNemo7539:
I wonder if android has battery test application, just to be put everything in the same play field? It's kind of pointless to compare subjectively.
[Fascinate Android Development] RacerXFD:
Well, I tried to be objective with this test I just did.

Here were my conditions:

Charge to full, write down the time it was at full charge which wasn't 100%.

Let it sit for one hour.

Write down the charge.

SV Conditions

Starting charge 99%

Ending charge 97%

UV Conditions

Starting charge 98%

Ending charge 96%

The results...

SV - 3% discharge / hour

UV - 2% discharge / hour

Errors analysis:

There are several issues with this test because they were not even at the same charge at the start. Batteries have their maximum charge at 100%, and the rate of decrease is not a linear decrease. More testing is needed to compare the results.

Also the duration is not long and other factors have not been considered such as background applications refreshing on their own. I will have to test for 8-10 hours of each at idling tomorrow to get an accurate measurement.

Currently, I'm still on the UV kernel and I'll publish my results tomorrow of the UV over the 10 hour period.

Then I'll try to not use my phone throughout the day and test the SV.

It would be nice if someone could test the SV and UV with moderate usage and write down the initial charge, final charge, and the duration between the measurements. And another using heavy usage.

Thanks.
[Fascinate Android Development] tjthebest:
Im confused with your math here...
[Fascinate Android Development] cckeeler:
Yeah, your math is off.....
[Fascinate Android Development] RacerXFD:
Thanks for the explanation. I'm an aerospace engineer. I did have to take a few courses in EE, but nothing to your level. So please let me know if I'm completely off on my testing.

I am pretty sure that the Devs know what they're doing, but I was getting tired of my low battery life and I was willing to test this theory of mine out for them. Again, seriously if I am completely out of the park in terms of this testing, let me know. And I'm ok with being called stupid as long as you teach me what I did wrong... :)

Yea, I completely forgot how with transistors, the math regarding voltage is handled differently than through a resistor. Are you telling me that the battery life will not be different between standard voltages and under voltages?

EDIT: I understand what you're saying about lowering voltage lowers current because the current has a linear relationship with the voltage in a MOSFET chip. Thanks, I had to read that like 5 times to understand and remind myself.

This is a complete waste of my time at this point because I know what's going on, but I wish to share my results anyways...

Ok here's where I got with the testing since last night. I realize that battery life is nonlinear. But i figure this is better than nothing.

But I did complete 8 hour test of SV at idle.

Starting charge percentage 94%

Ending charge percentage 82%

Which results in 1.5%/hour discharge rate at idle.

Will do the undervolt today. I'll document that in roughly 8 hours.
[Fascinate Android Development] nmyeti:
this is the correct answer. If some of you guys want to get hands on experience overclocking/underclocking and playing with voltages, i suggest you start on the PC side.

Typically when looking at a processor, you can undervolt right up until the level where your processor can't function at the reduced voltage and things start crashing. On overclocking heat or instability typically limit your upper range. Instability can sometimes be cured by adding move voltage, but then heat becomes even more of a problem. On the PC side you learn to balance this because you have easy access to most of the available parameters and the results of your efforts are easy to test.

In the phone world things become a little less transparent because in most cases the end user isn't the one turning the knobs and testing the results.
[Fascinate Android Development] RacerXFD:
I agree. So I'm not taking what iofthestorm is saying with a grain of salt. I really appreciate him taking his time to explain what he's saying. I figured I'd at least finish what I started in terms of experimentation. The results may turn out that UV equates to a better battery life than SV, but I subjectively feel like UV is causing my battery drain. I'm just trying to quantify it if it is. I haven't run a SV kernel since DJ05 so I'm not sure.

BTW, in case you are wondering, thanks for your input (no sarcasm). I really appreciate everyone saying what they think because it helps me put it all in perspective and understand the actual mechanics of the battery life.
[Fascinate Android Development] nmyeti:
In terms of what is causing your battery drain, you might find that the uv kernels are indeed worse on battery life as a side effect of something else in the kernel that doesn't like the code to undervolt the processor. In the phone world it's hard to understand the impact of a single change because of the way we are forced to alter these settings (complete kernel replacements). If you could isolate the changes from each other, you'd have better luck in your testing, but sadly that is simply not possible.

In a vacuum, if the processor can run at lower voltage @ the same clock speed, the lower voltage setting should be easier on your battery.
[Fascinate Android Development] RacerXFD:
Ok, basically I'm wasting my time... :)

Thanks for helping me understand.

So to restate what I've learned here...

Transistors behave differently than resistors and have a linear relation with voltage rather than inverse proportion with voltage.

This means that undervolting a processor should theoretically lower the power consumption of the processor.

Thanks for your help. I feel a little dumb for wasting everyone's time with this. :)
[Fascinate Android Development] yutsoku:
if you uv and oc power consumption is increased by power of 4

if you uv and uc power consumption lessens

if you ov and oc power consumotion lessens but processors become unstable

so if you undervolt you must underclock or your battery will die rapidly.

If you overclock then over volt, however not every processor is stable or built equally (but it's better on the battery)

if you overclock and keep stock voltage, same ratio applies to undervolting and over clocking, same if you keep stock and undervolt

This comming from someone a bachelors in electronics and 15 years of microprocessor experience (one of my good buddies)

And this is just my summed up version
[Fascinate Android Development] nmyeti:
If you look at it as an A-B test (although a-b-a would be a bit better) of two different kernels, then it's not a waste of time.

In a PC if i want to run my processor at a different voltage, i can boot into bios, change only that option (assuming your bios allows for this) and boot into the OS to test the changes (run prime 95 for a day or two, whatever floats your boat).

In the phone world, i'm flashing a kernel, testing, flashing a different kernel, testing and observing the results. What you are observing is the difference between those two kernels and how that code to create that difference interacts with the rest of the system.

It's not a useless test, but it is also not strictly a test of the processors power use with a given voltage setting. In the sense that it's comparing the battery life of two different kernels, but since everything is interconnected, it's hard to isolate the exact cause of a battery boost or drain.

I'll give a different example, I was using JT's Dj05 kernels. The voodoo version had absolutely zero audio pops and clicks, but the non-voodoo one was horrible for me when playing back audio. Since both are essentially the same except for the file system, it would be easy to draw an incorrect conclusion that links voodoo to solving the audio pops and clicks. We know this isn't true because there are voodoo kernels that suffer from the same audio playback issue.

In the end, try kernel a vs kernel b and report your findings, just don't position that we completely understand what's going on under the hood to create your findings, as we don't have enough control of the variables to really draw an accurate conclusion.
[Fascinate Android Development] iofthestorm:
Transistor current isn't linear with voltage, there are several equations for different regions of operation. Basically what I'm trying to say is what nmyeti clarified: in the vacuum, lower voltage will lower power consumption by more than linearly, perhaps quadratically or more. But there are too many variables to do tests in a vacuum. Comparing different kernels is still a worthwhile pursuit, but i think usually in our case the screen is what's draining battery the most.
[Fascinate Android Development] adrynalyne:
I don't know for sure, but that sounds like BS.
[Fascinate Android Development] nmyeti:
The smell test says it's BS also.
[Fascinate Android Development] imnuts:
I posted this in another thread, but since it's applicable to the topic here, I'll repost it:

I have been running a lot of different UV kernels over the past few weeks, and there is a point where you go from the UV helping your battery and it hurting battery life. From my testing, as the size of the UV increases, the processor will reach a point where it can't keep up at a given clock speed and will then move up as needed. It will get to a point where it's staying at 400/800 clock speeds more often than the 100/200 clock speeds, and the effect is negated.

I'm sure this point is going to be different on all phones, but for my phone is somewhere around a -100mV drop from stock voltages. It will help your battery when sleeping since your phone isn't doing anything, it will use even less power, but as soon as it tries to do something again, the battery life will tank. I also used PowerTutor to look at the usage trend for the CPU, and the system was using more power on average for some larger mV drops. I also started to notice lag as the drops increased, likely due to the processor being unable to keep up.

At the moment, I'm trying to see how a big drop on just the lowest clock speed, and then less of a drop on 200-1000 does. I also made a few adjustments to the scaling factors to help reduce lag at 100/200mhz and keep it in the lowest possible clock speed when running. So far, it seems somewhat promising, though I've only been running my current test for a few hours.
[Fascinate Android Development] nmyeti:
In the PC world, we can often get systems to POST at settings that will not completely boot into windows. This is because the processor is instable at those settings. It's also common to test the stability of an overclock or under-volt with a heavy run in of some benchmark program. It is not uncommon to have a frequency setting that will work fine for almost everything but the heaviest of torture tests. In many cases, the system doesn't completely shut down, but freezes or the test program crashes.

I suspect that in the lowest of under-volt kernels that you have tested, you are dealing with some back end freezes or errors (would be interesting to look at a log-cat) that are an indication of some instability, and it wouldn't shock me if the errors/pauses and application hangs that are common when a processor is instable are enough to drive the processor power management to kick up to a higher power state to compensate for the perceived increase in utilization.

So while I do not doubt your observation, I don't want anyone thinking that the lower voltage settings cause the processor to do less work per clock cycle, because that is simply not the case.
[Fascinate Android Development] imnuts:
That seems to be a good explanation as to what was happening. I didn't know what the lag was caused from directly, but I do know that it got worse as the voltage dropped. I actually had the android system restart (not full phone restart) once with the last test, so I'm guessing that it had to many issues and decided to just start over from scratch to see if that fixed anything. I never looked at the log cat output as I realize there is a point where the processor just isn't getting enough juice to run, and I figured I crossed over that point, but I'd guess that it was full of errors.
[Fascinate Android Development] yutsoku:
I'll trust my buddy with the degree and years of experience over a couple of people with what degree and experience?

Think about it, if you undervolt something where does the power come from to run at a higher clock speed? That means it has to pull more power to maintain the same voltage while going faster than standard clock speeds. If you UV and OC you will use more power because more current is needed.

When you OV and OC you then do not need to pull anymore current, but you have to OV and OC in the same ratio, or you will be unstable. This will cause excess heating... and heating is not good for processors. Why do you think there is heat on processors? It doesn't 'just get hot' it's because it has to release energy when it's not being used. When transistors produce more heat than it can cool it either triggers warnings for immediate shutdown and if the warning is bypassed or faulty then it can explode.

When you have millions of transistors in a processor, things get heated quickly, that's why you don't want to waste the energy and have it turned into heat...

Why do you think they make processors at specific voltages and clock speeds? It's not to be fast or to be overclocked, because it's about energy consumption.

I am not the expert, my friend is. This all was my personal opinion and the way I see it. He's the engineer not me.
[Fascinate Android Development] beray5:
Please quit it, no one with a BSEE and 15 yrs experience would ever be this stupid.

"if you uv and oc power consumption is increased by power of 4"

"if you uv and uc power consumption lessens"

"if you ov and oc power consumotion lessens but processors become unstable"
[Fascinate Android Development] nmyeti:
Truth be told a BSEE doesn't mean a whole heck of a lot when it comes to microprocessor design and for all we know the 15 years of experience could be 15 years in a bunny suit over at the Intel fab watching wafers made into chips. Just because someone's seen them built doesn't mean that they know how they work.
[Fascinate Android Development] imnuts:
Power usage would increase by a factor of 4 if the resistance of the transistors in the processor were changing. However, the resistance of the transistors is relatively constant, so power consumption should change somewhat linearly as voltage is raised/lowered.

Also, if the undervolt level is stable, and everyone agrees that less volts=less heat, then it should stand to reason that undervolting should result in less power usage. The cooler the processor, the more efficiently it runs, so by undervolting, you're preventing excess heat from building, there-by allowing the processor to run more efficiently at a given clock/voltage.
[Fascinate Android Development] yutsoku:
Building and designing are two completely different things...

Read on, it says that was in my words. He talked for about 15 minutes explaining... Try typing 15 minutes of explanation, see how big of a novel you write.
[Fascinate Android Development] RacerXFD:
No need for hostility. It doesn't matter if you're right and wrong. If anyone, I'm wrong.

I forgot that transistors cause a voltage drop rather than current increase like resistors. The current that hours through them does not drop. Thus under volting does not cause an increase in power consumption.

I just looked at my electronics book today after being wrong...

Anyways, the question from here is, what changes will make the battery life to go up?