I wasn’t around back then ;) But I think the big problem with steam tractors was since they were so heavy they would sink into the fields. I don’t think that was an issue really solved until gas powered tractors came around. Frank
> On Aug 26, 2025, at 2:35 PM, Adrian Godwin via cctalk <[email protected]> > wrote: > > Exploding boilers seem a lot worse than batteries. They can produce jets of > flame and toxic smoke but not cast iron shrapnel. > > > On Tue, 26 Aug 2025, 19:31 Steve Lewis via cctalk, <[email protected]> > wrote: > >> Your quote "to get into the head of those original engineers" is a great >> sentiment on what the hobby is about. >> >> I recall reading about early "steam tractors" - almost trains, before there >> were any tracks. Monstrous things, I can't recall if they were before >> steam ship engines - but exploding broilers was a problem (which I view as >> being akin to "exploding batteries" that we might occasionally deal with >> today- it happens now and then, as we still haven't perfected the tech {or >> at least, hadn't 10 years ago}). >> >> I'm reading more about those electric powered flying vehicles - with some >> becoming available around $120K? I think the Joby eVTOL recently did a >> first public flight between two airports. I've been flying one in MS >> simulator, neat to see that they might become a reality. The main >> naysayers of electric-anything vehicles tend to point to cold weather >> (northern winter) environments. >> >> >> Anyhow, those "personal minicomputers" from 1968-1969 are neat. It's a >> whole generation of computing that (IMO) is kind of forgotten about - but >> then again, they cost as much as a house then, so generally only business >> owners (like supermarket owners) could afford them. I suspect Gomez >> Addams had a few in their basement :) I've seen some Data General's of >> that era restored. I'm still trying to see if there are any functional >> DDP-116 or SEL810B around - but you're right, flip-switch programming is >> kind of a drag and working teletypes are hard to find these days. >> >> You mentioned having your own RAM card, like custom built? Someone >> recently made an SRAM based replacement RWS for the IBM 5110. Neat stuff, >> I never yet had the patience (or equipment) for that kind of detailed >> signal analysis to reverse engineer something like that. >> >> >> -Steve >> (voidstar / Domesticating the Computer) >> >> >> >> >> >> >> >> >> On Tue, Aug 26, 2025 at 11:26 AM Paul Koning via cctalk < >> [email protected]> wrote: >> >>> >>> >>>> On Aug 26, 2025, at 10:51 AM, Martin Eberhard via cctalk < >>> [email protected]> wrote: >>>> >>>>> Interesting for Tesla’s early history, but skip to 49:00 for a nice >> rack >>>> he is putting together with an 11/20. >>>>> https://youtu.be/88KHfX_kPIY >>>>> He also appears to be on the cctalk list. >>>> >>>> :-) Yes, I'm on this list. I was surprised to see Kim Java show that >>>> snippit of my PDP11/20 restoration project. I wasn't even aware that >> the >>>> camera was rolling at that point! >>>> >>>> So far, the CPU and the extended arithmetic element seem to be working >>>> great. I've got my own SRAM board >>>> < >>> >> https://deramp.com/downloads/mfe_archive/005-Documentation%20and%20Code%20by%20Martin/PDP11%20Stuff%20by%20Martin/Unibus%20Boards/Unibus%20RAM0ROM-Bootstrap/ >>>> >>>> in it. The RX211 is also working great, as is the DL11. I'm in the >>> process >>>> of restoring the RK11 disk subsystem (RK03 Diablo drives, external >>>> controller). I can now read, write, and format on one of the drives. >> The >>>> other has lots of work to be done. I need to tear both drives apart >>> enough >>>> to replace the rotted foam seals for the air-blower interface, and the >>>> rubber strip on the front door. I am also considering cleaning and >>>> re-lubricating the bearings on the positioner assembly. as they feel a >>>> little crunchy. Amazingly, I just bought new air filters for the >> Diablo >>>> drives! >>> >>> Nice! >>> >>> How do you load software into it? There's always the toggle switches if >>> you have enough patience. Or do you just update the ROM? >>> >>> For that machine, with a full load of memory, you have a bunch of OS >>> options. RT-11/SJ or /FB, DOS-11, RSTS-11. That last option would be >>> amusing: a machine quite similar to yours, with the addition of DECtape >> and >>> another 15 DL11 interfaces, is what my alma mater used for the college >>> timesharing system in 1973-1974. >>> >>> paul >>> >>> >>> >>
