Yeah, that seems to have been a pretty popular book, but I've literally never seen it. At the time, no library near me had it available, and ordering it from the UK was just too expensive for 13-year-old-me. I did have my own ROM disassembly, in two school notebooks, that I still keep to this day. Mu handwriting was pretty bad already then, though, so I prefer to think of all this as "lost in time" anyway.
Decades later, I did (pre-)order and read "The ZX Spectrum ULA", which documents, in painful detail, the inner workings of the custom Ferranti chip that powered most of the Spectrum.
This really did drive home the message that, no matter how much I thought I understood the low-level workings of my Speccy, there were still many lower-level layers left to explore. Which, I guess, is the central lesson of IT...
Decades later, I did (pre-)order and read "The ZX Spectrum ULA", which documents, in painful detail, the inner workings of the custom Ferranti chip that powered most of the Spectrum.
This really did drive home the message that, no matter how much I thought I understood the low-level workings of my Speccy, there were still many lower-level layers left to explore. Which, I guess, is the central lesson of IT...