[Interest] Qt 5.6LTS vs 5.7+

[Roland Hughes]

>Qt 5.6 is for those who cannot upgrade. If you can upgrade, upgrade.

>>How (un)likely is it that one can remain locked into 5.6 because of dependent
>>code that doesn't build against 5.7+? Qt's backward compatibility principle
>>should prevent that, no?


It is extremely likely for development to remain locked to a version. 
Forget for a minute identity theft enabling devices, also known as idiot 
phones but marketed as "smart" phones. Think about real systems. There 
are still systems locked at 3.3.

http://www.indeed.com/cmp/Peoplentech-LLC/jobs/Qt-Developer-888a0efa7f9c86b9?q=Qt+Developer+3.3

That posted contract is less than a month old. Once you get a large 
scale production thing going it becomes very difficult to change. If you 
are building/producing a medical device, be it a patient monitor, 
surgical robot or something in between FDA mandated new product testing 
kicks in when you make a significant change to the device, such as a new 
development library or OS. Some of these test paths can be many years 
long. It can take in excess of 7 years to get something like a surgical 
robot through all of the testing and field trials. (No, I don't think 
the process should be shortened. One of those things could end up 
cutting on _me_ some day!) Required test procedures for "minor" 
enhancements such as a new display feature are much less onerous.

I have heard tell of various electrical grid monitoring/control systems 
locked at 4.2. Others have told me some rail monitor/control systems are 
currently locked at 4.8 (as are a good number of medical devices) 
because once you get tested & trusted, you cannot risk a major change. 
You know where the current problems are with your tools and, more 
importantly, you know how to avoid/work around them.

The problem with Qt right now is that it is trying to serve multiple 
masters. It is trying to bring in script kiddies with this disasterrous 
QML project. I just ran a simple QML project test on the Raspberry Pi:
http://www.logikalsolutions.com/wordpress/information-technology/raspberry-qt-part-12-qml-blows-big-stinky-chunks/
Yimminy is it a resource pig. They are also trying to serve the 
real/true embedded systems developers slaving away to squeeze ever 
second of battery life and ounce of performance from an underpowered 
CPU. It is no secret that running a processor above 90% utilization 
draws more current than running it at 8% or less. If you want to know 
why trendy phone owners end up being "wall huggers" unable to get too 
far for too long from either a wall outlet or a USB port, it is the 
prevalence of scripting engines and applications written to use them 
keeping the processor pegged.

-- 
Roland Hughes, President
Logikal Solutions
(630)-205-1593

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