Software Reliability is how likely a program is to work without errors for a certain time in a specific setting. It's crucial for overall system reliability. Unlike hardware, software reliability shows how well a program is designed, not made. The complexity of software is a big reason why it can have reliability issues. There are models to predict software reliability, but choosing the right one is key. Measuring software reliability is still new, and there aren't great ways to do it accurately yet. There are ways to make software more reliable, but it's tough to balance that with time and money during development.