Lot of people are contacting me about this book and TSRs in general. I may not be able to help you via email or article comments. I request you to use this forum[archived] to post any questions, information and discussions on this topic. Thank you.
This book is for experts in C . It is not easy to follow this book if you dont have good knowledge of C . Since the book teaches TSRs , portability should be least of your concerns . This book has a lot of code and less than adequate explanation .
Overall a good book for learning to program TSRs in C . As TSRs were supposed to be written only in assembly you might encouter a few asm statements in the code . Be prepared for that also.