How the heap memory shared on all the opened application in Nokia Series60 devices?

[ajitkumar26]

Hi All,

If more than one application is opened at a time as in Nokia Series60 devices has the multitasking capabilities, bhow the heap memory will be shared?
Is the same heap memory will be shared by all the opened application or for each and every opened application there will be different heap memory?

Will it impact in the performance of the application running in front while others are running in the background?

Please help me...

Thanks & Regards,
Ajit

[symbianyucca]

in Symbian app application have their own Heap that is protected from others, basically only Kernel tasks can see all memory areas. There are of course ways on making shared memory areas if they are needed, but you would need to use Native programming for implementations.

[ajitkumar26]

Thanks for your immediate response!!!
My doubt is suppose I have opend more than one application and after some time I opened one more application which is developed in J2me.
So will it impact in the performance of the j2me application running in front while others are running in the background?

Thanks & Regards,
Ajit

[symbianyucca]

of course if other apps would consume enough memory it would start efecting the performance of all other running apps,anyway there is a system process that does close background apps when memory runs low, so in general you would not need to worry about it really.

[ajitkumar26]

of course if other apps would consume enough memory it would start efecting the performance of all other running apps,anyway there is a system process that does close background apps when memory runs low, so in general you would not need to worry about it really.

Thanks a lot.
Is it guarantee that allways the system process close background apps when memory runs low or it may not close sometime which will result in performance slow in other running apps?

Please clarify my doubts...

Thanks & Regards,
Ajit

[ajitkumar26]

Thanks a lot.
Is it guarantee that allways the system process close background apps when memory runs low or it may not close sometime which will result in performance slow in other running apps?

Please clarify my doubts...

Thanks & Regards,
Ajit

[symbianyucca]

Is there any specific reasons that you are so concerned about the issue ?

Basically there are always workarounds that often do work, and you could search for older discussion on them to find them out. Also the method is generally applicable only for UI-taks, i.e. it does not kill any background applications etc.

[petrib]

You could also read the Symbian Internals book to see if it answers your questions: http://www.developer.nokia.com/Commu...n_OS_Internals

And on sourceforge you can look up the Symbian^3 source code snapshot (a little over a year old), in case you wish to get that deep into how things work.

[r2j7]

Hello Ajit,

on Java ME specifics, the basics and considerations about heap usage on Symbian devices is explained on Java Developer's Library:

Java Developer's Library 3.12 > Developer's guides > Application framework > Hardware characteristics

http://library.developer.nokia.com/i...833C0E2C7.html

Symbian devices use dynamic memory allocation for Java, meaning that the memory heap reserved for Java grows and shrinks dynamically based on memory consumption. Because of this, the values returned by the Runtime.totalMemory and Runtime.freeMemory methods can vary over time. Symbian devices support a maximum Java heap size of 32 MB.

Not all Java objects are stored in the Java heap. Some objects can also be stored in the host OS memory. For example, only the handle for an Image is stored in the Java heap, while the actual bitmap is stored in the host OS memory. This can cause a discrepancy between the value returned by the Runtime.freeMemory method and the actual free RAM on the device. It is possible that an OutOfMemoryError is thrown even when it seems that the object should fit in the Java heap.

From S60 3rd Edition onwards, you can also use the com.nokia.memoryramfree system property to query the amount of free RAM on the device.

Regards,
r2j7