Author: Maya Posch

1404 Articles

A Brief History Of Cyrix, Or How To Get Sued By Intel A Lot

November 12, 2024 by 29 Comments

In a new installment on computer history, [Bradford Morgan White] takes us through the sordid history of Cyrix, as this plucky little company created the best math co-processors (FasMath) and then a range of interesting x86-compatible CPUs that would give competing x86 CPUs a run for their money. Even though Cyrix played by the rules of licensing agreements, Intel would keep suing Cyrix repeatedly since the 1980s well into 1990s, for a total of seventeen times until Cyrix counter-sued for patent violations in May of 1997.

This case was settled between Cyrix and Intel, with a cross-licensing agreement established. Unfortunately these mounting legal costs and the stresses of keeping up with the competition (i.e. Intel) was proving too much and Cyrix was sold off to National Semiconductor, who wasn’t enthusiastic about competing with Intel. After this Cyrix got split up into Geode (sold to AMD) and Cyrix Technologies (sold to VIA). Interestingly, VIA’s x86 patent licenses and patents ended up being the foundation of Zhaoxin: a joint venture between VIA and Shanghai’s government which produces x86 CPUs for primarily the Chinese market.

We looked at the Cyrix Cx486DLC processor a while ago, and why their 386 upgrade options were perhaps not that great. Their later CPUs have however left a strong legacy that seems to endure in some way to this day.

Minuteman ICBM Launch Tests Triple Warheads

November 12, 2024 by 75 Comments

On November 5th, the United States launched an LGM-30G Minuteman III ICBM from Vandenberg Space Force Base in California. Roughly 30 minutes later the three warheads onboard struck their targets 4,200 miles (6,759 km) away at the Reagan Test Site in the Marshall Islands. What is remarkable about this test is not that one of these ICBMs was fired — as this is regularly done to test the readiness of the US’ ICBMs — but rather that it carried three warheads instead of a single one.

Originally the Minuteman III ICBMs were equipped with three warheads, but in 2014 this was reduced to just one as a result of arms control limits agreed upon with Russia. This New Start Treaty expires in 2026 and the plan is to put three warheads back in the 400 operational Minuteman III ICBMs in the US’ arsenal. To this end a validation test had to be performed, yet a 2023 launch failed. So far it appears that this new launch has succeeded.

Although the three warheads in this November 5 launch were not nuclear warheads but rather Joint Test Assemblies, one of them contained more than just instrumentation to provide flight telemetry. In order to test the delivery vehicle more fully a so-called ‘high-fidelity’ JTA was also used which is assembled much like a real warhead, including explosives. The only difference being that no nuclear material is present, just surrogate materials to create a similar balance as the full warhead.

Assuming the many gigabytes of test data checks out these Minuteman III ICBMs should be ready to serve well into the 2030s at which point the much-delayed LGM-35 Sentinel should take over.

Why The Saturn V Used Kerosene For Its Hydraulics Fluid

November 11, 2024 by 38 Comments

We usually think of a hydraulic system as fully self-contained, with a hydraulic pump, tubing, and actuators filled with a working fluid. This of course adds a lot of weight and complexity that can be undesirable in certain projects, with the Saturn V Moon rocket demonstrating a solution to this which is still being used to this day. In a blast-from-the-past, a December 1963 article originally published in Hydraulics & Pneumatics details the kerosene-based hydraulics (fueldraulics) system for the S-1C stage’s gimbal system that controlled the four outer engines.

Rather than a high-pressure, MIL-H-5606 hydraulic oil-based closed loop as in the Saturn I, this takes kerosene from the high-pressure side of the F1 rocket engine’s turbopump and uses it in a single-pass system. This cuts out a separate hydraulic pump, a hydraulic reservoir, which was mostly beneficial in terms of reducing points of failure (and leaks), ergo increasing reliability. Such was the theory at the time at least, and due to issues with RP-1 kerosene’s relatively low flash point and differences in lubricity properties, ultimately RJ-1, RP-1 and MIL-H-5606 were used during checkout leading up to the launch.

In hindsight we know that this fueldraulic system worked as intended with all Saturn V launches, and today it’s still used across a range of aircraft in mostly jet engines and actuators elsewhere of the Boeing 777 as well as the F-35. In the case of the latter it only made the news when there was an issue that grounded these jets due to badly crimped lines. Since fueldraulics tends to be lower pressure, this might be considered a benefit in such cases too, as anyone who has ever experienced a hydraulic line failure can attest to.

Featured image: Gimbal systems proposed for the F-1, oxygen-kerosene engine with a fueldraulic system. (Source: Hydraulics & Pneumatics, 1963)

Welcome To SubTropolis: The Limestone Mine Turned Climate-Controlled Business Complex

November 10, 2024 by 32 Comments

After extracting all the useful stuff from a mine, you are often left with a lot of empty subterranean space without a clear purpose. This was the case with the Bethany Falls limestone mine, near Kansas City, Missouri, which left a sprawling series of caverns supported by 16′ (4.9 meter) diameter pillars courtesy of the used mining method. As detailed by [Benjamin Hunting] in a recent article on the Hagerty site, this made it a fascinating place for a  business complex development now called SubTropolis that among other things is used for car storage by Ford and long-term stamp storage by the US Post Office. (Check out their cool period photos!)

The reason for this is the extremely stable climate within these man-made caverns, with relative humidity hovering around a comfortable 40% and temperatures stable year-round at about 21 °C (70 °F), making it ideal for storing anything that doesn’t like being placed outdoors, while saving a lot on airconditioning costs. With Ford one of the biggest companies in SubTropolis, this means that many companies providing customization services for vehicles have also moved operations inside the complex.

With the only negative being a lack of daylight, it seems like the perfect place for many businesses and (evil) lairs, assuming electrical power and constant air circulation are provided.

Featured image: “Subtropolis” by [ErgoSum88]

Building A Motor Feed For The UE1 Vacuum Tube Computer’s Paper Tape Reader

November 10, 2024 by 9 Comments

Building a paper tape reader by itself isn’t super complicated: you need a source of light, some photoreceptors behind the tape to register the presence of holes and some way to pull the tape through the reader at a reasonable rate. This latter part can get somewhat tricky, as Usagi Electric‘s [David Lovett] discovered while adding this feature to his vacuum tube-era DIY reader. This follows on what now seems like a fairly simple aspect of the photosensors and building a way to position said photosensors near the paper tape.

As the feed rate of the paper tape is tied to the reading speed, and in the case of [David]’s also contains the clock for the custom tube-based UE1 computer, it determines many of the requirements. With 8 bits per line, the tape forms the ROM for the system, all of which has to be executed and used immediately when read, as there is no RAM to load instructions into. This also necessitates the need to run the tape as an endless loop, to enable ‘jumping’ between parts of this paper-based ROM by simple masking off parts of the code until the desired address is reached.

For the motor a slot car motor plus speed-reduction gear was chosen, with a design to hold these then designed in FreeCAD. Courtesy of his brother’s hobby machine shop and a CAD professional’s help, producing these parts was very easy, followed by final assembly. Guides were added for the tape, not unlike with a cassette player, which allowed the tape to be pulled through smoothly. Next up is wiring up the photodiodes, after which theoretically the UE1 can roar into action directly running programs off paper tape.

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Excerpt from 1995 Stratasys patent, showing the drawings of FDM layers, including brick layers.

Brick Layers: The Promise Of Stronger 3D Prints And Why We Cannot Have Nice Things

November 9, 2024 by 87 Comments

It is a fact of life that 3D printed parts from an FDM (fused deposition modeling) printer have weaknesses where the layers join. Some of this is due to voids and imperfect layer bonding, but you can — as [Geek Detour] shows us — work around some of this. In particular, it is possible to borrow techniques from brick laying to create a pattern of alternating blocks. You can check out the video below.

The idea of ‘brick layers’ with FDM prints was brought to the forefront earlier this year by [Stefan] of CNC Kitchen. Seven months after that video you still can’t find the option for these layers in any popular slicers. Why? Because of a 2020 patent filed for this technique by a 3D printing company which offers this feature in its own slicer. But is this patent even valid?

It’s no surprise that prior art already exists in the form of a 1995 Stratasys patent. The above image shows an excerpt from the 1995 Stratasys patent, covering the drawings of FDM layers, including brick layers. This covered all such ways of printing, but the patent expired in 2016. In 2019, a PrusaSlicer ticket was opened, requesting this feature. So what happened? A second patent filed in 2020 assigned to Addman Intermediate Holdings: US11331848B2.

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Exploring The Physics Behind Cooling Towers

November 9, 2024 by 21 Comments

A characteristic of any thermal power plant — whether using coal, gas or spicy nuclear rocks — is that they have a closed steam loop with a condenser section in which the post-turbine steam is re-condensed into water. This water is then led back to the steam generator in the plant. There are many ways to cool the steam in the condenser, including directly drawing in cooling water from a nearby body of water. The most common and more efficient way is to use a cooling tower, with a recent video by [Practical Engineering] explaining the physics behind these.

For the demonstration, a miniature natural draft tower is constructed in the garage from sheets of acrylic. This managed to cool 50 °C water down to 20 °C by merely spraying the hot water onto a mesh that maximizes surface area. The resulting counter-flow means that no fan or the like is needed, and the hyperboloid shape of the cooling tower makes it incredibly strong despite having relatively thin walls.

The use of a natural draft tower makes mostly sense in cooler climates, while in hotter climates having a big cooling lake may make more sense. We covered the various ways to cool thermal plants before, including direct intake, spray ponds, cooling towers and water-free cooling solutions, with the latter becoming a feature of new high-temperature fission reactor designs.

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