One of my regular commenters on A&D, Random832, wrote the following in response to my inclusion criteria for Things Every Hacker Once Knew.
On “common knowledge at the time”, I think the problem with dismissing things as “fascinating but obscure trivia” means too much exclusion of the real facts behind things that were already forgotten or inaccurately known, and reduces its value as a historical document. There’s also the fact that the intersection between, say, the Lisp and Unix hacker spaces seems to have been tenuous enough to cause some things to have been lost in translation […] – maybe there was never really anything every hacker once knew, just some things some hackers once knew, and other things other hackers once knew, all worth preserving. I think arbitrarily drawing lines around “provides too much historical context” runs the risk of the document being better described as “Things Eric Once Knew”.
I think this comment raises real issues that deserve to be squarely engaged. I’ve omitted one sentence that I think is based on a a factual misunderstanding in order to focus on the large questions.
The first and most obvious point is that this is not a new set of issues. I already had to engage them in connection with the Jargon File a quarter century ago. My answer now, as it was then, is that of course every historian has unconscious biases and selectivities. But if we let that paralyze us we could never write any history at all. This would be a cure worse than the disease that Random832 is pointing out.
There are equally obvious ways to address this problem. One is doing now as I did in 1990: exposing my process to peer review and willingly engaging in a public conversation about both fact and interpretation – not just accepting correction from other witnesses but inviting it. This is more than most historians are willing or even practically able to do.
In this particular situation, I think I am a reliable negative filter (if I didn’t know it, it wasn’t common knowledge) but a less reliable positive one (if I knew it, and thought everyone else did, it was common knowledge).
The reason for this is precisely the position that Random832 sees as a possible weakness: in the crucial period 1976-1985 I lived at the intersection of three subcultures. They were: the Lispers, the Unix minicomputer guys, and the micro hobbyists. It wasn’t a perfectly symmetrical situation; I was deeper in the Unix culture than in in the Lispers and micro guys. But it gave me a breadth of perspective that nobody confined to those individual subcultures could quite match.
But putting it that way also risks overstating the divergence. Because, for example, essentially everybody who learned his chops before the early 1990s either had to deal with serial terminals day to day, or (if they were on a workstation or micro) had recent memory of doing so. There simply was no way for this not to be true, given the technological surround. Similarly for modems in the pre-DSL era.
I am, therefore, actually pretty confident about the ubiquity of most of what’s in there – that it isn’t just things Eric once knew. I get some confirmation of this from the rather high volume of traffic related to the document in my mailbox. The overwhelmingly dominant tone is “Thanks for the trip down memory lane”; I don’t think anybody has yet said “I didn’t know that”, or suggested that I’m too focused on one of the subcultures. I have been alert for such criticism because I understood the issue going in.
Looking over the whole document with this in mind, these are actually just two pieces that worry me that way. One is the ‘graph about the Space Cadet keyboard; the other is the discussion of standard vs. TTL serial. They present opposite problems.
On the one hand, I’m not certain the Space Cadet keyboard was common knowledge at the time. It became so later, but that might have been a retrospective effect of the Jargon File.
On the other hand, I now think the details of the level distinction in RS-232 were common knowledge then – even though I, less hardware-savvy then than now, only vaguely knew of it – but I could still be wrong; that might have been been micro-culture only, which is why I was only vaguely aware.
Whereof one cannot speak, one must remain silent; but if one chooses to bear witness, the hazards of imperfect memory and limited perspective are ever present. The best we can hope for is to mitigate them by cultivating humility and openness.