38
votes
How to modify software to become real-time?
Fast does not mean real-time and real-time does not mean fast.
Real-time means that the date when outcome is delivered is as important as its value. In other words, if the outcome has a correct value ...
- 15.5k
15
votes
How to modify software to become real-time?
As @mouviciel already said, real-time and fast are really two independent properties, even though many real-time deadlines imply that a relatively fast response is needed.
When writing real-time ...
- 75.7k
10
votes
Why is Modbus/TCP not considered a real-time protocol?
Sometimes (due to noise, collisions, ...) packets get mangled and/or just plain lost (dropped due to congestion, lots due to a router going offline, etc). TCP is supposed to recover from this by ...
- 3,975
9
votes
Is real-time processing a synonym for streaming?
Depending on the context these may mean the same. But to me these concepts are quite different.
Streaming is about communication, not about "real time". Characteristics of a stream would be:...
- 2,256
8
votes
How to modify software to become real-time?
I suppose the two-sentence explanation of realtime is that a realtime system is designed to understand and control the worst-case response time from inputs changing to outputs changing.
That requires ...
- 14.6k
7
votes
How to write integration tests for a distributed system highly dependant on current date and flow of time?
Never manipulate the actual time time or speed of the system you are testing on just to test time logic. It's hard to get right and may have lots of unforeseen side effects.
Instead, decouple all ...
- 110k
7
votes
How to avoid the accident that an item price is updated right after a user clicks purchase?
Say you changed your price at 11:39:46am. The customer looked 5 seconds earlier and ordered five seconds later. Had you changed the price ten seconds later, everything would have been fine. If you try ...
- 46.7k
7
votes
Critical Infrastructure Language Selection
The choice of language isn't really that important in your scenario. You need to look at the architecture as a whole to see whether it can meet the requirements (and maybe you need to look at the ...
- 17.1k
7
votes
Accepted
Is real-time processing a synonym for streaming?
As the other answer mentions, a 'stream' is an ordered sequence of events, and the concept of 'streaming' typically refers to transmission of events.
'Streaming' also generally implies that events are ...
- 12.1k
6
votes
What is so different about RTOS compared to normal programming?
By not treating all Interrupt Service Routines (ISR's) as the highest priority.
The kernel of an RTOS is preemptible where as a GPOS kernel is not preemptible. This is a major issue when it comes to ...
- 112k
5
votes
Why is Modbus/TCP not considered a real-time protocol?
Let's start again!
Under perfect conditions TCP would never need (e.g.) retries and times would be bounded. Under the exact same perfect conditions TCP would also never be needed - it'd be a silly ...
- 3,975
5
votes
How to get real time notifications, when a database change (insert, update, delete) occurs?
For PostgreSQL I know a way to get notification from the database when a row changes.
use trigger when insert / update / delete occurs.
when event occurs send a notify to a client socket.
be sure you ...
- 51
5
votes
Critical Infrastructure Language Selection
My question: I remember from the ‘90’s and early 2000’s there were flame wars about using Java on the server, and if that was the right option because Garbage Collection introduces potential for ...
- 28.4k
5
votes
Accepted
When should I be worried of Time of check time of use vulnerabilities during database queries?
So, the best option that came to my mind is asking myself whether the portion of code would really harm if exploited. In this case the user may delete a post milliseconds after another process strips ...
- 28.4k
4
votes
Accepted
Strategy to maintain data efficiency in real time application
If the list is small and changed frequently, it may be the best to let the subscriber query the full list from time to time. However, if the list is huge and changes occur seldom, you could log any ...
- 211k
4
votes
Develop Windows based application with 1/10th milisecond precision
According to this MSDN article section, Windows can definitely provide adequately accurate measurements for you to know whether your instructions are being executed fast enough, depending on the ...
- 2,472
3
votes
Architecture for real-time application, avoiding duplicate messages for queues with no active consumers
I am not sure to see the values of the queues here, a direct bidrectionnal communication would be better, and would solve your current problem, when the user come back from hibernating his computers, ...
- 3,516
3
votes
Cross-compiling Java app to run directly on ARM
You can compile Java to binary for a target using LLVM.
A quick look at the docs shows support for many ARM variants.
https://llvm.org/svn/llvm-project/java/trunk/docs/java-frontend.txt
Also another ...
- 3,553
3
votes
How should a service communicate with an activity in real-time?
You can also use Pending Intent,Event Bus or Messenger for real time communication from service with activity.
Check out my blog post at below link which covers all these approaches with example-
...
3
votes
Accepted
Do 1:1 mobile video call face filters belong on Client or Server?
Sometimes you just need to decide what the minimum hardware requirements are. Mobile devices are a fickle bunch. Small. Not as powerful. Spotty data connections. You could have a valid business reason ...
- 40.8k
3
votes
How to avoid the accident that an item price is updated right after a user clicks purchase?
A possible solution is to copy the price to the "order" record once the order is put in the cart.
This way, the price in the cart may still be different from the price previously listed in ...
- 130
3
votes
Deterministic behavior using RTOS with preemption
What kind of software architecture or mechanisms can be used to ensure that, using a real time os with preemption, everything that has to be run in a cycle is indeed run during that cycle ? How to ...
- 10.3k
3
votes
Is real-time processing a synonym for streaming?
At the margin the distinction may blur, but typically a stream is either continuous (in the sense of incessant) or reactive immediately, whereas a batch is scheduled explicitly on a rhythm or involves ...
- 10.3k
3
votes
Is real-time processing a synonym for streaming?
There are some parts of streaming that { can, must, should } be real-time. Whether this is the case, and if so, which of the requirement words applies, depends on what particularly you're streaming. ...
- 268
2
votes
Accepted
Can heavy use of the service pattern substitute pure functions without losing benefits?
As the referenced article mentions, this is very close to mimicking some basic OOP in Haskell, though, as it mentions, it provides first-class composition. It's also closely related to dependency ...
- 6,701
2
votes
how to calculate communication waste in Scrum ?
I think that trying to measure communication would be waste, in the Lean sense. It's incredibly difficult to do. The easiest way to do it would be self-reporting, but that adds unnecessary overhead to ...
- 83.7k
2
votes
how to calculate communication waste in Scrum ?
There are significant flaws in the reasoning behind this question.
What is the reason for assuming that intra-team communication around cancelled features is "communication waste". That term implies ...
- 39.4k
2
votes
How to detect real time change in API response
You can't push information from the end point itself. But since you control the deployment process you can add a push interface as part of the deployment.
For example.
Add a second interface which ...
- 78.5k
2
votes
Accepted
How to test software with near-real-time requirements?
Congratulations, your testing has now progressed to the stage where 'integration testing' is required.
You have mentioned that in addition to u it testing you have done some general testing so far as ...
- 921
2
votes
Strategy to maintain data efficiency in real time application
The sole purpose of the notification is to notify.
Your notification should enough information to the client so that the client can decide what it must do to update itself, including retrieving any ...
- 200k
Only top scored, non community-wiki answers of a minimum length are eligible