Would anyone be willing to help a slow learner?

[dmac05]

I plan on going slow and taking my time with the material here and really making sure I understand it. But I am only on the second page in Chapter 1 and already not understanding why the truth table has the values it has in the last column and how the boolean expressions are being created from it. I don't want to clutter up the message board with simple questions so I thought maybe if I could email someone a question from time to time that might be a better way for me to go about it. Thank you very much.

[ashort]

I could help over email.  Not sure if my email is visible for you

[ashort]

Of course others may benefit from your questions, so perhaps this forum is best…

[WBahn]

Don't worry about cluttering up the message board with simple questions. If a thread has no interest for someone, they can simply ignore it. But I can pretty much guarantee you that you are not the only one struggling with whatever is holding you up. There are plenty of people for which this whole subject is so new and foreign that it takes quite a bit of time and help getting started down the path, so the discussion here will almost certainly help out other people down the road.

[WBahn]

dmac05 wrote

I am only on the second page in Chapter 1 and already not understanding why the truth table has the values it has in the last column and how the boolean expressions are being created from it.

Which edition of the text are you using?

If you are talking about Figure 1.1 in the 1st Ed.,  then that is just an example of a Boolean function of three variables and the last column is the output of the function for each possible input. It is just an example and the values in the output are arbitrary -- the author could have (and perhaps did, though probably not) flipped a coin eight times to get the eight values.

For our purposes, we don't care what the function means. Perhaps (just making this up as I type), x represents the output of a thermostat, y represents the state of a switch, and x represents whether or not water is present in some tank. The person designing the system needs to use those three input to determine whether a heater should be turned on and, after doing a lot of analysis and tests, has come up with the last column of that table.

However that function came about, and whatever it means, we don't care. It's been thrown over the wall to us and we just have to implement it.

The text doesn't show, yet, how to go from the truth table (which defines how the function is supposed to behave) to the Boolean expression (which, hopefully, has the same behavior). Instead, it is essentially saying, "Hey, one of the kids next door thinks that this expression will work. Let's verify that it really does."

So, with that in mind, do you follow the steps used to verify that the equation really does produce the results in the table? If not, we can take a step back and work through that. If so, then if you would like to, we can look at one way (there are several) to come up with that equation starting from the table.

[a1ph4byte]

dmac,

Me and a couple of people from Reddit just bought the book and will be working through the project together, message me if you're interested in joining the group!

[dmac0505]

Thank you for the replies everyone. Sorry it has taken me so long to get back. I've been very busy and may continue to be for another month or so. But I wanted to ask, is it ok learn from the first edition of the text or should I buy the 2nd version in the hopes of it explaining things clearer to me? Thank you.

[WBahn]

I think the first edition of the book is quite good, but the authors did go to some effort to improve the second edition based on what seemed to be common sticking points for people. I have no idea whether those improvements will be a benefit to you (or anyone in particular).

[dmac05]

I see and understand thank you. I am going to be starting a different course tomorrow but, if I have time, I am anxious to go through the nand2tetris material as well. So, I will ask questions as I have time - thank you.

[burge91]

just take breaks and come back to it wwhen you have the energy. i have owned the book for probably 5 years and am still barely half way through it xD

it's a tough course, but also extremely good. you have to be persistent and dogmatic and be willing to try things in different ways. however it could just be that it's too difficult, in which case you can just move on. we all have our limits.