What Do SZ and VSZ Mean in HP-UX `ps` Output?

In HP-UX, when you look at the output of the `ps` command, you'll see two important metrics: SZ and VSZ. SZ represents the size of the process's core image, measured in kilobytes, while VSZ stands for the virtual size of the process, also in kilobytes. The key difference between the two is that VSZ indicates the total amount of virtual memory that the process has allocated, which includes memory that may not yet be used. Essentially, it reflects how much memory the process has reserved for potential use, but it doesn't necessarily mean that this memory is actively being utilized. In contrast, SZ is more about the actual size of the core image itself. It's important to note that neither SZ nor VSZ directly indicates the actual memory usage of the process. They provide insight into how much memory is allocated or reserved, but they don't tell you how much of that memory is currently in use. In some cases, if a process doesn't share resources, SZ and VSZ might be the same, but this is not common. Even when they are equal, it doesn't accurately reflect the real memory consumption of the process. So, if you're trying to determine how much memory a process is actually using, you'll need to look beyond SZ and VSZ.