In 2003 I was sentenced to 6 years in a Texas prison. The how and why isn't relevant, other than to say it was a terrible mistake I made seven years prior. At that point, I was about 5 years into my tech career. I wasn't in there for a "hacker" crime, so I was in general population, and had more freedom than the author did.
As for prison conditions, not much I can add to the conversation. It was hot, miserable, crowded, things we all know about. No real opportunity to improve yourself; you mostly have to focus into your own little niche and do what you can to keep yourself safe and maintain who you are as a person (it's easy to lose yourself in "prison games")
Served a full six year sentence, despite never getting trouble. Parole release for "good behavior" is a cliche.
During my time there, my wife divorced me and my father passed away.
There was some adjustment upon getting out. (2009) However, the first couple of computers I used were actually running XP, so that was an easy adjustment. I think the biggest adjustment was how much more prominent mobile device use was (in 2003 I think I only received a text from one person ever, on my fancy monochrome flip phone). From a development standpoint, gettting used to AJAX was interesting, but to be honest, I did my best to keep up in prison, with a handful of books I had sent to me.
I remember the first line of code I wrote, in a language I considered myself and expert in. It felt familiar, but like I was pulling memories from a fog. Eventually, the "muscle memory" of working in the language came back, but I can see how it could be very frustrating for someone who was out of the loop longer than I was.
First job was a remote role, $20 an hour. Some previous writings I still had online sold the employer on my knowledge, and I actually beat out 4 people in the interview. I was able to leverage some relationship I had before, get some additional remote gigs, and continue to build my income and my life back up.
I was actually to be quite successful that way, building up my network, finding contracting. Of course, I have constraints: traditional employers are typically not an option, which includes most w2 contracting roles. I've had to keep learning of course, and have more flexibility than the usual person who can carve out a niche in one main technology or stack. However, I could work around the issues of having a felony conviction and maintain a market-level income. I've even had a couple of situations where I did have to discuss my past and was able to work through it. (Again, sticking to strict 1099 contracting, and small companies is the key) However, contracting is no longer a need: through my personal connections, I was able to turn was one of my gigs into a full time significant role with all of the full time income and benefits advantages you'd hope for.
I don't mean to diminish the challenges that many face, but I just wanted to point out that a lot of presumptions aren't automatically true.