It means that Thursday evening, when you're tired, it's easier to pick yourself up and work, because doing so gets you a _better_conversation_ on Saturday. I'm a cellist - this comes from private music lessons.
See also http://en.wikipedia.org/wiki/Bloom's_2_Sigma_Problem . In that study, the median person learning one-to-one performed at the 98th percentile in a control group. That's huge!
You're not being fair to IRC. IRC can just as easily give you a one-to-one relationship with another person who cares. Private messages exist, among other means. Moreover, the experience can be completely asynchronous. You don't have to both be available to make progress.
The main benefit of something like Understudy is to mediate the introduction of users to mentors. There is something to gain from a sustained conversation with the same mentor, but Understudy can make no more guarantees about the availability of your mentor than IRC can. Furthermore, that both the mentor and the mentee have to pay $5 if they're using the app more than two hours a month demolishes the potential userbase, not to mention that you also need an iOS device. IRC is multi-platform, free, and already attracts the sort of individuals that would be capable and willing to mentor users in something like SICP.
Studying SICP (or anything) can involve different "modes":
Reading and doing exercises will often be solitary. Q&A could definitely be asynchronous (IRC works great for that!). But we're talking about explaining what you've learned; only in synchronous conversation will you get the back-and-forth "wait what? How's that work?"
A hard part of learning is figuring out exactly what you don't know; conversation is remarkably effective at elucidating that. Where do you feel uncomfortable while speaking? Where does your partner look especially confused or skeptical? The human connection gives you expression, body language, tone of voice, etc. in a quick feedback loop.
(disclaimer: not involved in creating Understudy, but I'm a happy user!)
There is something to be gained from synchronous conversation, but what you've listed can be done asynchronously.
In either case, my point was IRC doesn't have to always be synchronous. When you're both available, the conversation can be synchronous.
I agree that there is a huge benefit from having a synchronous, spoken conversation, but my reply was contesting that "Understudy gives you is a one-to-one relationship with another person who cares" in contrast to IRC. IRC can do exactly that, so what sells Understudy is certainly something different.
But your way is the way I can recommend.
Still, I give them the benefit of the doubt that their software may be helpful. I'm not going to get an iPad for it though.
Yes. I used DrRacket with Neil Van Dyke's SICP package http://www.neilvandyke.org/racket-sicp/ , and that's what we recommend.
> What about MIT Scheme in Emacs?
It seemed more complicated to get running, but one of our beta testers is doing it that way, and he's happy with it.
#lang planet neil/sicpIt seems to that the term covers the hardware associated with iOS and doesn't imply anything one way or another about the company which manufactures it.
It is not as if there is just one "iPhone" and one "iPod" and one "iPad". There are diverse models of each and little point in being pedantic over all the retinas and 2' and 3's and 4's and GS's and plain old S's and mini's and nano's when the important point is that one cluster of them is required to use the product.
Folks, you don't need proprietary software or an iThing to get help with SICP. Hop on #scheme on freenode and check out http://schemers.org/ for resources.
Get yourself a good Scheme implementation like GNU Guile or Racket and get hacking.