Yep, similar experience here. My first computer was a Tandy / Radio Shack Color Computer. It had a 6809 processor (8/16-bit precursor to the 68000) @1.8MHz, 4k of RAM (upgradable to 64k), 16k or 24k ROM memory with a quite expansive MSFT Extended Basic Interpreter (supposedly the last ROM OS & BASIC that had assembler written by BillG himself).
I taught myself BASIC, assembler, graphics programming and game programming on that machine over a period of about four years of hacking around on it (including hand-commenting some significant chunks of the ROM). By the time I retired it for a shiny new Amiga 1000 in 1986 I'd upgraded it to 256k of bank switched RAM with a soldered-in hack board, added four floppy drives, various I/O boards and learned OS/9 (a UNIX-inspired multi-tasking, multi-user OS) and hacked in my own extensions to the ROM OS (including adding my own new commands and graphics modes to the BASIC interpreter).
It started out as a lot of trial and error but, on later reflection, ended up being a surprisingly thorough grounding in computer science from which to launch my career. That 6809 machine was also the last time I really felt like I was aware of everything happening in a computer from interrupts to registers to memory mapping down to the metal.
I taught myself BASIC, assembler, graphics programming and game programming on that machine over a period of about four years of hacking around on it (including hand-commenting some significant chunks of the ROM). By the time I retired it for a shiny new Amiga 1000 in 1986 I'd upgraded it to 256k of bank switched RAM with a soldered-in hack board, added four floppy drives, various I/O boards and learned OS/9 (a UNIX-inspired multi-tasking, multi-user OS) and hacked in my own extensions to the ROM OS (including adding my own new commands and graphics modes to the BASIC interpreter).
It started out as a lot of trial and error but, on later reflection, ended up being a surprisingly thorough grounding in computer science from which to launch my career. That 6809 machine was also the last time I really felt like I was aware of everything happening in a computer from interrupts to registers to memory mapping down to the metal.