NM234, contact your local DOC and ask for a tour, or when the next oneis going through. You will be required to submit your SSN, etc, for clearance.
As for your housing questions, I have no idea how your local DOC does it, but we use an extensive classification process based on two overall factors - Insitutional Risk, and Public Risk, resulting in what we call a P and I score. Many factors are used, (I have never worked Programs, so I couldn't tell you what factors they are, but I think it's available on our public website), then score of 1-5, 5 being the worst, is used to determine where an inmate is incarcerated. Other factors are also used now, including age, violent/non violent crime, etc, in housing in cells. Also, sex offenders are segregated from others. So, on my yard, I have thugs who are also rapists, but on a GP yard they're just thugs. Mostly murderers are in higher custody units, but some leak down to us, due to one factor or another. A new classification system in being worked in, to help avoid another Lewis tower incident.
Once again, we are not "guards". And, no, officers are not allowed to "beat up" on inmates. I personally know a LT who self-demoted to inmate for that. Uses of force are strictly controlled, taped, reviewed, etc. Any planned use of force, cell extraction, etc, has to have approval from the top before moving in...all because of liberal lawyers and lawsuits. I have seen good staff injured because they didn't want to get sued for a use of force. We always have theright of self defense, but assault on inmates is a huge no-no, and WILL result in criminal prosecution.
Last, police keep no eye on us - they don't come in. We are the law enforcement inside the walls. In many states COs are LEOs. PD don't like coming inside, surrounded by convicted felons, approx, at my yard, 33.5 to one, unarmed. That's OK, I wouldn't like thier job. At least, in here, the teams are clearly defined. PD rarely enters farther than the sally port/intake, dropping off or picking up for county jails/new warrants.
We do have our version of Internal Affairs, known as CIU, who takes care of staff investigations. They have full arrest powers, and have been known to remove bad staff in cuffs.
I hope that explains more. I see your view of COs is inspired by depictions like that of Walker:Texas Ranger, where we are either stupid, corrupt, or both. The reality is far more boring.