Qt vs Symbian C++

kamalakshantv · wrote on 11 Jun 2010, 15:50

[quote author="varunnarula" date="1275576380"]I have tried installing the qt_installer.sis which comes with the (beta) Qt SDK and during installation, the option is provided, but I noticed that all the library components installed on the C: drive.

Have you tried installing any Qt application (bundled with the Qt libraries) on the mass memory. Do let me know, this is something I want to try out.[/quote]

There was an issue with qt_installer.sis and it need to be installed on c: only. It was said to be fixed in the newer versions.

However, apart from this you can install any Qt Application in the mass memory.

kamalakshantv · wrote on 11 Jun 2010, 15:52

[quote author="varunnarula" date="1276181289"]bq. The proper solution to this problem is for Nokia to stop creating devices with too little space on C:!

That is exactly the problem. 128 MB will just not cut it. At the very least, 256 MB is required. The N900 has some virtual memory, any idea if something similar can be done on Symbian ?

Take the N97 for example, and with Maps, Quickoffice, Qt and browser cache, the memory quickly fills up. With virtual memory, this problem could be solved.

[/quote]

I do agree N97 has memory issues. But I think most new devices will handle these issues now.

varunnarula · wrote on 11 Jun 2010, 16:49

The qt_installer.sis was from the beta 1 of the Qt SDK released recently. Have yet to try the one from the latest beta, I believe it is 2.0.

varunnarula · wrote on 11 Jun 2010, 16:50

I hope the N97 is the last phone with 128 MB :-)

snowpong · wrote on 14 Sept 2010, 09:02

[quote author="QtK" date="1276271405"]
There was an issue with qt_installer.sis and it need to be installed on c: only. It was said to be fixed in the newer versions. [/quote]

The reason we force Qt on C: is because otherwise applications startup can take several seconds - we're talking 15 seconds for example. That is simply not acceptable for an end user.

Now, the reason it is slow to load, is because of an overzealous security check on Symbian, where they will re-read and calculate a CRC/MD5/checksum of a library loaded by an app too many times (imagine it's re-reading QtGui 4-5 times for an app startup, just to make sure it's not been tampered with). This check only kicks in for libraries installed on mass memory, so if it's on C this doesn't even happen.

So, basically - is it possible to have Qt installed somewhere else than C, yes. Is it recommended, no. And that's why the qt_installer.sis is hardcoded to put it on C.

kamalakshantv · wrote on 14 Sept 2010, 09:27

[quote author="snowpong" date="1284454969"][quote author="QtK" date="1276271405"]
There was an issue with qt_installer.sis and it need to be installed on c: only. It was said to be fixed in the newer versions. [/quote]

The reason we force Qt on C: is because otherwise applications startup can take several seconds - we're talking 15 seconds for example. That is simply not acceptable for an end user.

Now, the reason it is slow to load, is because of an overzealous security check on Symbian, where they will re-read and calculate a CRC/MD5/checksum of a library loaded by an app too many times (imagine it's re-reading QtGui 4-5 times for an app startup, just to make sure it's not been tampered with). This check only kicks in for libraries installed on mass memory, so if it's on C this doesn't even happen.

So, basically - is it possible to have Qt installed somewhere else than C, yes. Is it recommended, no. And that's why the qt_installer.sis is hardcoded to put it on C.[/quote]

Thank you for making it clear.

Does Nokia smart installer do the same. Because at times you have only a few MB left in C: on your device.

snowpong · wrote on 14 Sept 2010, 09:31

[quote author="QtK" date="1284456470"]
Thank you for making it clear.

Does Nokia smart installer do the same. Because at times you have only a few MB left in C: on your device.
[/quote]

The Smart Installer will force it onto C as well, and fail gracefully if there is not enough space.

kamalakshantv · wrote on 14 Sept 2010, 09:37

[quote author="snowpong" date="1284456669"][quote author="QtK" date="1284456470"]
Thank you for making it clear.

Does Nokia smart installer do the same. Because at times you have only a few MB left in C: on your device.
[/quote]

The Smart Installer will force it onto C as well, and fail gracefully if there is not enough space.

[/quote]

Will this delay in launching be observed in anyway, if an end-user application has some libraries and are not placed in C:. Or this affects only the Qt runtime libraries.

snowpong · wrote on 14 Sept 2010, 09:45

[quote author="QtK" date="1284457056"]Will this delay in launching be observed in anyway, if an end-user application has some libraries and are not placed in C:. Or this affects only the Qt runtime libraries.
[/quote]

Typically no. It's a special case. You'll experience it if:

Your library is big (2-5megs for example)

You have lots of plugins that link back to your library again

So in general, don't worry. If you have a library with your app it's not gonna hit you in most cases.

kamalakshantv · wrote on 14 Sept 2010, 09:55

[quote author="snowpong" date="1284457553"][quote author="QtK" date="1284457056"]Will this delay in launching be observed in anyway, if an end-user application has some libraries and are not placed in C:. Or this affects only the Qt runtime libraries.
[/quote]

Typically no. It's a special case. You'll experience it if:

Your library is big (2-5megs for example)

You have lots of plugins that link back to your library again

So in general, don't worry. If you have a library with your app it's not gonna hit you in most cases.

[/quote]

Thank you for the clarification.

jaak · wrote on 16 Sept 2010, 08:04

I read on forum nokia discussion forums that the smart installer is currently useful only for deploying Qt apps to a very few Symbian devices. The reason cited was lack of space on c drive on most of the current devices. Is this true ? I have one project I'am planning to do in Qt. If the above is true I have to revert back to native Symbian api.

kamalakshantv · wrote on 16 Sept 2010, 08:33

[quote author="Jayakrishnan.M" date="1284624241"]
I read on forum nokia discussion forums that the smart installer is currently useful only for deploying Qt apps to a very few Symbian devices. The reason cited was lack of space on c drive on most of the current devices. Is this true ? I have one project I'am planning to do in Qt. If the above is true I have to revert back to native Symbian api.[/quote]

Smart Installer too installs Qt libraries to C:, so if there is not enough space it cannot get installed.

kamalakshantv · wrote on 16 Sept 2010, 08:34

But then going forward more devices are expected to be launched with Qt pre-installed.

snowpong · wrote on 16 Sept 2010, 09:40

Here is the "best documented list":http://www.forum.nokia.com/Distribute/Packaging_and_signing.xhtml#article1_a I could find of the current devices OVI / Smart Installer likes.

jaak · wrote on 16 Sept 2010, 10:50

[quote author="snowpong" date="1284630014"]Here is the "best documented list":http://www.forum.nokia.com/Distribute/Packaging_and_signing.xhtml#article1_a I could find of the current devices OVI / Smart Installer likes.[/quote]

Thanks for the link.

xsacha · wrote on 3 Dec 2010, 04:59

There is a new SmartInstaller v1.1 by the way.
http://info.publish.ovi.com/?p=596
Mandatory as of today but was released last week.

Some stuff may have changed with regards to this topic.

snowpong · wrote on 3 Dec 2010, 11:39

Thanks for the update

But - why can't they put a date on news releases like this? They say "Starting today, the new Nokia Smart Installer v1.1 is now mandatory for all Qt- based Symbian apps submitted to Ovi Publish" yet there is no date anywhere...

xsacha · wrote on 3 Dec 2010, 14:29

It says it was released on the 24th in the wiki that page links to. Unless you meant when it became mandatory. Date of article was 2nd of December I think. I remember seeing the date before but now that I look, it's not there :O

By the way, just after this announcement one of my smart installer apps passed QA. So it's only for new submissions.

xsacha · wrote on 4 Dec 2010, 03:10

But Nokia have stated that all Qt runtimes will be backwards compatible with Qt4.6.3. So not really a mess. The only things that aren't back compatible are the 'labs' that you shouldn't be using in production app anyway.

Also, they are fixing the Smart Installer thing. You won't have to say it may download up to 13MB of additional files anymore.

The only markets I wasn't able to distribute apps using SmartInstaller were Mainland China (without licencing partnership) and Korea (no idea?). But I don't think those had anything to do with Qt or Symbian C++.
I'm not sure why an operator would restrict Qt. Makes no sense really. Surely the customers would debrand their device or yell at their operator and not come back.

xsacha · wrote on 4 Dec 2010, 04:17

Well as they are removing the "download up to 13MB of additional files" restriction, maybe they are also making the Qt download come from Ovi Store.

What's the domain that Ovi Store uses? There's no reason they couldn't host Qt Installer on there.