Hacker News Reader

Comment by tptacek | Hacker News Reader

I wanted to find something debunking the notion that userids at CompuServe were based on the PDP-10s that ran the service, because it seemed improbable that anyone was running a major online service on PDP-10s by the time the Microsoft Chicago betas were circulating, but, nope: that's real.

http://www.inwap.com/pdp10/compuserve.txt

View on HN

CompuServe had their own pet PDP-10 vendor after DEC discontinued the line: https://en.wikipedia.org/wiki/Systems_Concepts

They were still running PDP-10-compatible systems from SC up until the original Compuserve service ended in 2009.

You can still buy a brand-new PDP-10 compatible in a certain sense... XKL, another SC-like company, still exists, and they make specialized network gear. As far as I know, all the control planes still run a TOPS-20 derivative on a PDP-10 compatible architecture, even today.

The Digital Antiquarian has a wonderfully in-depth series on CompuServe and the surrounding ecosystem of early internet firms, which includes this detail:

https://www.filfre.net/2017/10/a-net-before-the-web-part-1-t...

This reads like the show bible for season 2 of Halt and Catch Fire. I thought the technical details of that season were all wrong, but, guess not.

Very interesting but the story in that post is dated 1988, long before Windows 95. I'm calling it a "post" because I'm not sure what it is: Email? Message? File? The header:

  File name:  compus.txt
  Date:  31-Aug-88 15:44 EDT
  From:  Sandy Trevor [70000,130]
  Subj:  PDP-10 History

  TO: Joe Dempster

Right, but it ends just as CompuServe is making a major new purchase of PDP-10 gear.

The date is repeated below, so that's not a typo. He then talks about how Compuserve has been using PDP-10s for the previous 17 years. Compuserve was around in 1971??

Edit: Holy shit, Compuserve was founded in 1969(!) as a subsidiary of an insurance company.

https://en.wikipedia.org/wiki/CompuServe

The "70000,130" appears to be a CompuServe User ID, for what it's worth.

I think I read on HN recently that McDonald's restaurants' accounting ran on PDPs (10?) until the 90s. Can't find any info online to back that up though.

Wouldn't surprise me. Code that works has a tendency to stick around longer than people think. There's a lot of institutional knowledge built into that codebase. It would be like firing an employee of 20 years who works for nothing and hiring someone for millions of dollars.

This is the most succinct description of this phenomenon I've ever seen.

As technologists, we often wonder why new, better tech doesn't dominate. If something suffices, why change?

Inertia is vast for the core systems that power large organizations. But these legacy systems do eventually yield as new requirements render change non-negotiable. Those ancient, messy, arcane, yet somehow supremely reliable systems tend to become frozen reflections of the organization they serve. It does eventually make sense to replace them when the organization has changed sufficiently that the reflection is no longer accurate.

New regulations, new products, new markets, new acquisitions, divestment, outsourcing... these are the real drivers of change that move an organization’s technology forward - not the new tech itself.

Because maintenance and replacement (in some way) is good practice. Quit thinking of tech as some magic thing that will never go bad and start thinking of it like any other piece of equipment. Regular maintenance is required. Replacement may be required.

Because generally the new tech isn’t better. It’s just newer.

McDonalds ran a lot of stuff on SCO Unix, those references are pretty easy to find because they're all through SCO's marketing materials.

Fun fact: SCO Unix started out as Microsoft Xenix, which started out as a license of Unix:

"Microsoft, which expected that Unix would be its operating system of the future when personal computers became powerful enough, purchased a license for Version 7 Unix from AT&T in 1978"

https://en.wikipedia.org/wiki/Xenix

Reply on news.ycombinator.com