The first "portable" computer fit in two trailer vans and weighed 20 tons


Originally published at:


See Traveller was right! Computer power is measured in tons.


Well, you’ve got to start small. Sort of.


When I was a kid we didn’t have Chromebooks. We had to lug two ten ton trailers to school, through a blizzard, uphill, both ways!


I remember the trouble I had going to catch my first Ram Upgrade…


They were fast though. Bit hard to fit in the socket.

Yak yak yak.


Tons of water displaced, or as a unit of weight?


Apparently 14 cubic meters, or 1,000kg of Liquid Hydrogen.




or two grid squares.


Hats off to the engineers who trucked around mercury delay line memory. It’s a mobile superfund site in the making if there was an accident.


But to be fair, half of that weight was the battery.


depends on the quantity of mercury. Remember, mercury was used in everything-- thermometers, barometers, lots on engineering equipment.


You would be amazed at how much mercury was in the average building only 20 years ago or so. Back around 2006 when mercury thermostats were no longer allowed to be sold, a college that had recently built a dorm asked about whether it was wise to replace the mercury thermostats in the dorm rooms. There was 175 separate stats, each with at least 28 grams of mercury. That added up to over 10 lbs.

In 2001 the total mercury used in just thermostats was 14.6 tons. Remember this mercury was held in thin walled glass capsules, and with no laws that mandated recycling you can assume that much mercury entered the trash stream every year just from thermostats.

BTW, mercury relays and contactors can still be bought and used. They are sealed better, and mercury recycling is much more available today, but still


How far we have come.


I remember my chemistry teacher passing around a bottle of mercury so we could all dip our fingers in to feel how dense it was. No gloves needed!


That’s probably the only perk of building a portable computer in the 1950s. CERCLA wouldn’t become law for almost 30 years; so, while a spill would mean data loss and potentially the mercury amalgamating with all the gold plated components goddamn it corrosion short circuit nightmare hell probably with some of those zesty vacuum tube drive voltages thrown in; a few ambient neurotoxins would be a-OK.


Never mind the mercury in the delay lines, the notion of moving a vacuum tube computer by truck, and then expecting it to work properly, must have caused the builders of this thing a lot of anguish. Those machines were finicky, with many thousands of connections and delicate parts to cause trouble.


To be fair, there were earlier computers able to move around under their own power:


I’m having trouble accessing TFA right now(speaking of portable computer reliability…), so I apologise if this is already answered; but I’d be curious if they used (in addition, one assumes, to trying every mechanical engineering trick that can attenuate shock) any of the attempts at improved modularity that were hitting the scene at the time. Something like Project Tinkertoy was still a fairly preliminary Navy research thing in 1953; but it shows that the idea was out there, and, while going modular means more connectors to worry about it also means more connectors where ‘re-seat module’ is a viable troubleshooting/repair step.