[nickcw]

I'm not old enough to have used a PDP-11 so I read through the assembly code description with interest.

Wow, it seems so modern. I've used a lot of assembly languages over the years but I'd feel immediately at home here. Nice sensible orthogonal instruction set with enough registers and a stack pointer. It reminded me immediately of ARM assembly - what a breath of fresh air that was when it came it.

I never realised quite how much influence the PDP-11 had on computer architecture. I knew about it's software legacy but I suspect that was enabled by it's ground breaking architecture.

[mrandish]

My first computer had a 6809 with 4K of RAM and I learned assembler on that 6809, which was greatly inspired by the PDP-11 architecture. My second computer was an Amiga 1000 with a 68000, a CPU even more directly a successor to the PDP-11 than any other. As far as I knew, those two PDP-11-like systems were computer architecture. Orthogonal instruction sets, user and system stacks treated just like any other register, layered interrupts, indirect addressing, memory mapped I/O, auto-increment/decrement, relocatable zero page, contiguous flat memory map, relative addressing that made position-independent, re-entrant code trivially easy. Yeah, in the 1980s, I led a sheltered, happy computing life.

It was around the mid-90s by the time I tried x86 assembler. I don't think "shocked" quite captures the experience. It was more like disbelief, then something akin to abject horror, which finally just faded into creeping existential dread. Before the X86, I loved coding in assembler but the nicest thing I can say about x86, is it motivated me to learn C as fast as possible. :-)