It is same as when you attach debugger to an application, but this is at the lowest Operating system level.

Since kernel debugging means having a parallel machine, (physical or virtual) inspect the whole operating system in which your application is running. There are more than 10 alternatives to OllyDbg for a variety of platforms, including Windows, Linux, Mac, Online / Web-based and BSD. If you are into OS debugging/advanced patching, your 'someone' may be referring to whats called a Kernel debugging. Since even if you patched the wrong file/screwed up, all you need to do is restore the VM. The first debugger works in user mode, while the second one can debug kernel-mode code. IDA - The best-of-breed binary code analysis tool, an indispensable item in the toolbox of world-class software analysts, reverse engineers, malware analyst and cybersecurity professionals. This is a simple plugin that automatically installs the latest OllyDbg.exe from your build directory if you start 圆4dbg. The main candidates are 圆4dbg and WinDbg. When comparing X64dbg and Hiew, you can also consider the following products OllyDbg - OllyDbg is a 32-bit assembler level analysing debugger. This plugin is not even close to usable Come in Telegram, Gitter or IRC to discuss it with us. Thus experimenting, patching, destroying an application inside VM will have zero impact on your actual machine (at least theoretically, since in real world malware etc can escape from a VM). Implementation of OllyDbg 1.10 plugin SDK for 圆4dbg. Point is VMs are relatively reusable and disposable. That someone may mean don't patch the application, since it will ruin your original copy. Your question is relatively broad with at least 2 possible scenarios.

Ollydbg vs x64dbg