As I most often am not able even to ask the right question, much lesser to understand answers, I have decided to read thoroughly Knuth's TeXbook. But on Appendix B--Control Sequences--I find reference to INITEX, no longer used in Mac Distributions. What would you suggest to a student that thinks "it is necessary to study Chemistry in order to learn how to strain a good coffee", as my problem, as I understand now is to learn how to make Formats--as stated in Knuth's TeXbook--or whatever/however I name it now? Or, should you suggest another learning path? I see no good in asking ready solutions from experts whose language I am not yet able to understand!!!!!
If you want to study TeX (as opposed to LaTeX, ConTeXt or other formats), then a book to read is TeX by Topic by Victor Eijkhout. You can buy a printed copy from Lulu. Or, if you wish to read from the screen, just call texdoc texbytopic in a modern distribution.
After you read and understand Victor, return to The TeX book and reread it.
texfrom your shell (orpdftexif you want PDF output). – egreg Apr 12 '12 at 20:15initexfor your system. In particular, do read section 3.6 (starting on p. 6) on the subject of "Creating format files". – Mico Apr 12 '12 at 20:54