Why can’t a compiler just “think more” about optimization?

This happens to me from time to time: I compile my code with the highest optimization level (-Ofast) of the allegedly fastest compiler (GCC) of one of the fastest languages (C/C++). It takes 3 seconds. I run the compiled program, measuring performance. Then I make some trivial change (say, marking a function inline), compile it again, and it runs 20% faster.

Why? Often I’d rather wait a few minutes or even hours, but be sure that my code is at least hard to optimize further. Why does the compiler give up so quickly?

As far as I know modern architectures are super complicated and hard to a priori optimize for. Couldn’t a compiler test many possibilities and see which one is the fastest? I effectively do this by making random changes in the source code, but that doesn’t sound optimal.

Does anyone know what this encoding format for passwords is? I think it is a decimal array but I can’t seem to convert it

During a penetration test, I ran across a server that was storing passwords in its database in what seems to be a binary array of sorts:

password_table  1,10,11,21,21,11,21,13,00,00,00,000 11,61,19,11,46,108,09,100 110,118,100,107,108,117,123,62,108,108,62,62 

(slightly edited for confidentiality)

The server in question is a Tomcat server and the application is running a Java program. I considered that this might be a array of sorts but I can’t seem to convert these arrays into anything readable or usable. Does anyone have any ideas?

Should we think of 5e’s greatsword as an especially beefy longsword, still able to be carried at the hip?

Historically, greatswords were so long they were impossible to carry at your hip, so you typically carried one around with it resting, point-up, against your shoulder. One benefit justifying this inconvenience was their reach. However, in 5e, greatswords are not “reach” weapons. Should we therefore think of the 5e greatsword as just an especially beefy longword–twice as heavy, but still short enough to be carried at the hip? Or, since we’re telling fantastical stories about fictional epic heroes, do we simply buy into the Hollywood back sheath, no matter how unreasonable that’s been shown to be in real life?

Bonus Question: Does your same answer apply to 5e’s other heavy and 2-handed but non-reach melee weapons, the maul and battleaxe?

Is it reasonable to think that most magic users would be familiar with the spell Silence and thus know easy ways to counter it? [closed]

The spell Silence as described in the PHB:

For the Duration, no sound can be created within or pass through a 20-foot-radius Sphere centered on a point you choose within range. Any creature or object entirely inside the Sphere is immune to thunder damage, and creatures are Deafened while entirely inside it. Casting a Spell that includes a verbal component is impossible there.

The spell is obviously a useful tool against magic wielders, but I’m trying to get clarification on its limitations.

Would it be common for magic users to recognize the Silence spell and know easy ways to counter its effects? For example, a wizard familiar with the spell might know to just run a short distance in any direction to leave its area of effect, and then continue casting spells. I understand that different types of characters will have different knowledge of spells, but Silence isn’t a high level spell and would seemingly be well known to many mid- and even low-level magic users.

The related question below might shed light on how a character would react to the Silence spell, because they might instead interpret the effect as being deafened.

Related questions:

Deafness vs Silence – How to distinguish Darkness from being blinded and Silence from being deafened?

Practice question for security plus I think is wrong. Integrity vs availabilty

So there is the following question on a practice test:

Which service are you addressing by installing a RAID array and load balancer?

A. Confidentiality B. Availability C. Accountability D. Integrity

The correct answer according to practice test is “Integrity”.

Can someone explain this and why it would not be Availability? Not understanding how availability wouldn’t be the correct choice.

I want Lay on Hands, but I think Paladins are campaign-wreckers and won’t play one. What are my options?

I’ve DM’d for Paladins as PCs before, and my experience is that they can unwittingly derail a campaign, even without any effort or powergaming on the part of the player. As such, now that I’m a player, I refuse to play a Paladin. I don’t want to inflict campaign-derailing sidequests just because I accidentally broke the Code and have to go on a redemption quest just to be a useful party member; I don’t want to torment my DM with at-will detect evil, like I have been tormented.

I still like the character concept and some of the abilities though; I especially like their Lay on Hands class feature. So, as a first stab at finding acceptable alternatives to the Paladin class, I was wondering if there were abilities one could acquire that work just like or very close to Lay on Hands, but without being a Paladin.