What is Runtime?

" Every action performed has a calculated time period, so does a program for which the time phase matters more."

When a program is executed, it consists of a series of instructions that guide the software through executing the action. Once all instructions are done, the program is set to run and this running phase or period is when the code is executed.

The runtime is essentially a system for displaying the time period during which a program is running. The programming lifecycle is also known as the software lifecycle because it is the time it takes for instructions to be properly executed.

Runtime is the last phase of the program lifecycle also known to be the execution phase of the program. If there is any disruption in the runtime, then you can find that there is a crash in the program.

Program lifecycle phases

While executing a program or running a code, there are sections of other commands and their respective time periods. In a programming lifecycle, the runtime is the final phase of execution.

Program lifecycle phases

Edit time

The codes written might have errors while running, the program might have bugs and there will be various other issues. Edit time is when the code of the program is edited which includes bug fixes, refactoring and other additional changes.

Compile time

The work of a compiler is to translate the input code into the programming language for execution to occur. So generally compile-time refers to the phase in which the code is compiled and translated to the simpler programming language.

Link time

A linker is a computer program that takes two or more object files into a single executable file. Link time is the programming phase during which the linker is in action, which occurs after the compiling of code is completed.

Distribution time

The process or phase through which the program is translated in the form of source code to the user. It is basically a process of transferring a copy of the code that is executed in the program.

Installation time

Installation is the action of setting up the program to be ready to be executed. The time at which the program is being executable is known to be installation time.

Load time

Load time is related to the operating system which usually loads the program or libraries to be executed. The action performed is that during the loading time the contents of the program that is being executed is read before running it.

How does runtime work?

As said before, the runtime is the last phase in executing a program. So the process goes like this.

  • For the most part, the editing and bug fixing is done in the program.

  • After which it is the work of the compiler to translate the codes into a programming language.

  • The linker and compiler prepare the object file for execution by linking the files present in the program.

  • After the program has been loaded, the loader links all the files to memory, linking the program with the external libraries so that execution can begin.

When the program is executed and this is where runtime plays its part.

Runtime systems and runtime environments are integral parts of how instructions and codes are executed.

Runtime systems: It is part of the OS which helps in running the main program along with some additional programs.

Runtime environment: This is the place or environment in which the program is executed.

Runtime library: This is the link between the compiler and runtime, where the instructions are stored to help in executing the program.

What are runtime errors?

These errors can take different forms, including runtime errors. A runtime error is nothing but a glitch in the program or code during the process of execution.

The presence of a runtime error can be detected if the program runs slowly or if the software crashes. These errors can be caused by a variety of factors.

  1. Coding error: This is generally caused due to the presence of bugs in the program. Even a manual error can result in the crash of the program.

  2. Leakage of resources: A program being executed needs to be compiled and the result needs to meet expectations. When there is a lack of resources during execution, it falls under resource leak.

  3. Memory leak: Memory leak is also a form of a resource leak in which the programmer usually fails to delete the resource that is no longer needed for execution.

  4. Buffer overflow: This occurs when code or a program overruns a memory or code of a nearby memory location.

Programmers constantly use the word debugging while they work. Debugging is nothing but the process through which you detect and remove the errors or bugs present while executing the program.

What is exception handling?

Just by detecting the errors, it is not going to fix automatically. This is where exception handling pops in which is the process of fixing or responding to the errors and bugs that are detected while executing the program.

You do have automated exception handling languages that are designed and enabled in certain programming languages which helps in fixing the runtime errors. But generally, it is done manually by analyzing and observing the abnormalities in the runtime.

Examples of Runtime

1. Android Runtime (ART)

This is an application runtime that is associated with the Android OS. It performs actions like translating the byte code into instructions that are used by the device during its runtime. It uses AOT as well as JIT compilation for its performance.

2. Common Language Runtime (CLR)

This is the runtime environment that is designed for the Microsoft .NET framework. It uses the JIT compilations for the execution of the program and it is highly language-specific (i.e., only the OS can read the instructions)

3. Java Virtual Machine (JVM)

JVM is a virtual machine that is used to run JAVA programs that are written and executed in other languages. The main work is to execute the codes related to the JAVA environment and libraries related to it.


Runtime is basically a critical piece of software that is needed for the execution of a program, as this entire article suggests. The main use of runtime is that programmers can easily detect bugs present during the execution period.

That's the prime reason to understand runtime systems and other systems related to them.

Further Reading

  1. What is Latency?
  2. Guide to Containers
  3. RuntimeError: Working outside of application context in flask

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