I'm a little surprised by their approach. I mean, it did work, it is cool, and it is the most important thing. Still I can't stop thinking that I wouldn't sleep before I wrote an assembler and a disassembler. Judging by the presentation they had no assembler and disassembler for several months and just lived with that.
asm/disasm can help to find typos in listings, they can help to find xrefs or even to do some static analysis to check for mistake classes they knew they could make. It wouldn't replace any of the manual work they've done, but still it can add some confidence on top of it. Maybe they wouldn't end with priors 50/50 for the success, but with something like 90/10.
Strange. Do I underestimate the complexity of writing an asm and disasm pair?
He mentioned a few times that writing an assembler was a no-go.
It would have taken much more time than they had available, and since an assembler would be a new tool, it would have required certification. (So, even more time and paperwork.) Plus, they had incomplete docs and there is no working copy or simulator of Voyager here on Earth. So any assembler written would by definition be incomplete or inaccurate.
Well, it was a totally bespoke CPU, and we don't have any working models on earth.
Writing an assembler for a bespoke CPU is one thing, many of us have done it as a toy project, but stakes are a bit different here. You'd have to mathematically prove your assembler and disassembler are absolutely 100% correct. When your only working model is utterly irreplaceable and irrecoverable upon error, it probably takes a lot more resources to develop.
What you're saying is that "creating a tool requires validation, but not creating a tool and winging it doesn't."
Which is engineering-speak ridiculous.
To debug anything you need a mental model of the thing in question. With that mental model you can build a software-based model of it (a simulation), you can document it, or both. But for some reason you believe that documentation doesn't require validation, but the tool that expresses a model represented by the documentation does not.
Realistically speaking, they have 2 days between command and response, so they have plenty of time to write a simulator.
No but the time it would take to build the assembler and validate its output would take more time than just writing the patch by hand. It’s for a craft that isn’t going to last more than 5 more years tops anyway.
I'm with you. I feel like having automated tools - even though they aren't certified - would be an improvement over doing it all manually in both time and reliability.
asm/disasm can help to find typos in listings, they can help to find xrefs or even to do some static analysis to check for mistake classes they knew they could make. It wouldn't replace any of the manual work they've done, but still it can add some confidence on top of it. Maybe they wouldn't end with priors 50/50 for the success, but with something like 90/10.
Strange. Do I underestimate the complexity of writing an asm and disasm pair?