How would you test a ‘Mobile’ version of IM? What are some key differences between testing this version versus a desktop application?
First of all you need to account for unstable connectivity - the program should be ready to deal with temporary and permanent network coverage losses.
Resources consumption (memory footprint, network bandwidth and CPU time) is also to be considered. Noone wants a program that drains the battery in an hour, occupies all memory or causes a giant bill to the owner.
Both memory requirement and network bandwidth has to be kept to as low as possible...
adding to sharptooth's answer, notifications on sending/receiving a message. Support for voice chat/video chat via available hardware :)
Related
All mobile devices have limited storage options. Therefore, it is imperative for a tester to test an app under low memory conditions. To simulate these conditions, a tester has to fill device memory using dummy files. This is very tedious and time consuming process.
Is there any app or any proper steps to overcome this situation..!!
If you're using emulator to perform test execution have variety of options to control memory availability (both RAM, internal storage and SD card) Just limit the size of the memory type you need to the application size + 5% and you'll get "low memory" environment
There are also other ways already present at Stack Overflow on how to simulate memory shortage. See links below:
How can I force memory pressure for Android debugging?
How do you simulate low memory in the Android emulator?
You can specify the VM Heap parameter when creating the AVD. However, for a real device it doesn't look like you can change the parameters.
A colleague of mine is getting a quote from a software developer that involves serial communication, and in their quote, the developer makes the the following statement:
...Windows 7 operating system, which uses a non-real-time serial communication setup.
Is it true that Windows 7 does not support real-time serial communication? To clarify on what it is meant by "real-time," the project deals with robot automation and any delays in communication (such as from buffering) could cause damage to the product, or stop the production line. I can not find any evidence to either support or deny this claim. I don't believe it to be true though, and I think it probably has more to do with them using VB.Net for development.
The 'real-time' term used here does not actually refer to anything in the serial communications bus.
However, it does have to do with the fact that the windows multitasking scheduler is not designed to allow for realtime tasks which have hard deadlines.
See this question for some info Why is Windows not considered suitable for real time systems/high performance servers?
Lets pretend you have a particle accelerator hooked up to your computer and you have to ensure that every 10 microseconds the magnet train switches to power the next set of cells but windows decides that it's time to apply some Windows Update patches. Your photon stream wouldn't get redirected properly and could cause damage to the system.
It is a fairly nonsensical statement, Windows itself is not a real-time operating system. It cannot provide hard guarantees that user mode code is going to respond quick enough. Other than thread scheduling delays, a simple mishap like getting the pages of the process swapped to the paging file is enough to cause arbitrary delays in getting it running again. An attribute of any demand-paged virtual memory operating system. So of course a "serial communications setup" cannot be either, assuming you are not contemplating writing ring 0 kernel code. Nobody does.
It is not a practical problem, the only point of using a serial port is to talk to the controller for the robot. Which provides the real-time guarantee.
You could only get in trouble when you command the robot to make an unrestricted move and use an external sensor to get it to stop. Not uncommon when you need to find an object whose location you don't know. A decent controller knows how to do that, avoid implementing it in your Windows code. Solid overtravel protection built into the robot itself that triggers an e-stop is necessary anyway, you can't trust that sensor either.
No, Windows 7 (and in fact all of the mainstream Windows releases) are not Real-time operating systems. To clarify what is meant by a real-time operating system:
A real-time operating system (RTOS) is an operating system (OS)
intended to serve real-time application requests. It must be able to
process data as it comes in, typically without buffering delays.
Processing time requirements (including any OS delay) are measured in
tenths of seconds or shorter.
A key characteristic of an RTOS is the level of its consistency
concerning the amount of time it takes to accept and complete an
application's task; the variability is jitter.[1] A hard real-time
operating system has less jitter than a soft real-time operating
system. The chief design goal is not high throughput, but rather a
guarantee of a soft or hard performance category. An RTOS that can
usually or generally meet a deadline is a soft real-time OS, but if it
can meet a deadline deterministically it is a hard real-time OS. [2]
An RTOS has an advanced algorithm for scheduling. Scheduler
flexibility enables a wider, computer-system orchestration of process
priorities, but a real-time OS is more frequently dedicated to a
narrow set of applications. Key factors in a real-time OS are minimal
interrupt latency and minimal thread switching latency; a real-time OS
is valued more for how quickly or how predictably it can respond than
for the amount of work it can perform in a given period of time.[3]
Note that most of the time real-time operating systems are less efficient (i.e. have lower throughput), which is why none of the mainstream operating systems are real-time (e.g. real-time editions of Linux use completely different kernels) - its only worth it in cases where timing at a very precise level is absolutely critical.
Windows CE is a real-time operating system Real-Time Systems with Microsoft Windows CE 2.1
I have stellaris LM4f232 evaluation borad. I have ported free rtos , sysbios to stellaris lm4f232 board and successfully developed an gps tracking application . But I always wanted to port uc linux for my board . my question are
i) is there any material to port uclinux to any controller
ii)what are necessary knowledge I required to do the same
I have googled a lot . I did n't get the right information, but I have seen posts that its difficult ,but I cant able to realise the same .any help????
iii) what is the road map to achieve it , what are the knowledge I should need to achieve this
Linux, even uCLinux requires considerable memory resources; you'd want to start with at least 2Mb for the boot device and 16Mb of RAM (although a minimal system can be booted in as little as 4Mb). On a microcontroller, this means that you must have external memory.
Another issue is that Cortex-M devices are optimised to run code from on-chip Flash memory, having separate buses for ROM and RAM so that data and instructions can be fetched simultaneously. uClinux must run from external RAM, which has a detrimental effect on the performance, and you will be unlikely to achieve the 1.25MIPS per MHz figure the CM4 is otherwise capable of. It is possible to arrange for time critical code to be placed in on-chip flash is necessary, but it is of course a limited resource.
Some good advice on the issues of deploying Linux on a Cortex-M device can be found here
I would suggest to have a look on buildroot which as far as I know can be build for this board.
adding to #Clifford , you can use u-boot (bootloader) ,already configured for many boards ,if your board is not on list you can edit it.,
Given the multitasking function of iOS, will other applications that are currently sleeping affect my app (which is currently active) performance or memory consumption?
Absolutely. Any application that is running in the background (within the various parameters for when that's legal) will impact CPU availability. Apple apps can run in many more situations than 3rdparty apps, and they also will compete with you. I've particularly had trouble with Mail.app in the past.
Memory performance is a bit trickier, but yes, other applications are in memory at the same time and you can definitely generate memory warnings sooner with other applications in memory than you would otherwise. In principle, you should be able to get as much memory eventually as you would without other apps running, but that's not completely true. In particular, don't forget that Apple's apps don't always follow the same rules as 3rdparty apps, and if they're eating a lot of memory, they may or may not be killed.
The other performance consideration is network bandwidth, and this is most certainly a way that background apps may compete with you. I don't believe Apple is applying any bandwidth limiting on background apps, and downloading large files is a prime background activity. (There is some discussion that AppStore may decline apps that hit the network too hard while in the background, but I'm not aware of an official position on this. In any case, it it certainly legal to use some bandwidth in the background, and that's bandwidth not available to the foreground app.)
No they won't.
When the active app needs more memory being used by background apps, it automatically kills them off so the active app can use the resources.
I am looking for an API to monitor the tasks running on a plain iPhone (no jailbreak). Those are about:
look for CPU usage (my main concern).
look for memory usage.
look for disk usage (how many read/write)
look for network usage (how many bytes sent and received by network: 3G, Wifi, GSM).
is it possible to rely on the IOS simulator running on a Mac (or should I test my application directly on the device)?
I think I can look into the system C libraries (sigint, etc.) but I am not sure to be able to retrieve this information except for the current applications running. I know some monitor applications run on the global usage but I would like to be able to find the information process by process.
If someone can provide some links or something useful, I will start a deeper investigation then.
CPU usage can be found by looking at the code from this related question:
iOS - Get CPU usage from application
Memory usage:
Available memory for iPhone OS app
And here are a couple threads that talk about how to find out about the applications or tasks currently running:
Can we retrieve the applications currently running in iPhone and iPad
How to get information about free memory and running processes in an App Store approved app? (Yes, there is one!)
How to get the active processes running in iOS
The answers to these questions may point you in the direction you'd like to head towards.
Good luck!
The Activity Monitor should get you what you're looking for. You should be able to observe RAM, CPU, and VRAM usage for each iOS process. This is a default tool installed with xCode. Very handy.