Is /proc/sys comparable to the Windows registry?

Question

Does Linux's /proc/sys expose similar functionality to that of the Windows Registry or are they incomparable?

From what I've seen, both allow the user to change various arcane system functions by changing key values, so they seem alike. Linux tends to focus on configuration through various binary interfaces and the kernel config file/kernel modules from what I've seen (this may be incorrect, and if so, what is the proper/popular approach?) but /proc/sys has its place as well. I saw someone get flamed on an Arstech blog for suggesting they are similar, so perhaps I'm wrong here.

Answer 1

The Windows registry is a database which stores most of the settings for a Windows system as a whole, whether that’s the kernel, drivers, applications, etc.

Linux’ /proc/sys, aka sysctl, exposes configurable kernel settings only, and only at runtime. It can be complemented by tools like sysctl or systemd which allow values stored in text files (/etc/sysctl.conf etc.) to be applied at boot; but it doesn’t store any values itself beyond a running instance’s lifetime.

So they are really quite different. The Windows registry exists whether the system is running or not, persists from one boot to the next, and stores information for far more than the running system (including long-obsolete settings). sysctl only ever provides access to information valid in the running kernel, nothing beyond that, and it doesn’t persist.

Answer 2

The eqivalent of the windows registry in linux would be closer to the /etc directory of config files and the hidden config files in the user's home directory that start with a period.

The unix config files are much less structured than the windows registry, and both location and syntax varies from application to application. On the other hand, most of them are intended to be directly edited, and many are designed to be machine editable as well.

While probably just as many in linux are dangerous to edit in that errors in editing can be disastrous to the system, typically applications are designed so that they will tell you about syntax errors in the config files, and fixing such errors is typically not too hard.