PDP-11 Trouble With A Ruthless Power Supply Issue

January 15, 2024 by Maya Posch 9 Comments

After [David Lovett] of [Usagi Electric] was donated a few cars full of DEC PDP-11 minicomputers of various flavors and vintages, he passed on most of them to loving homes, but kept a few of them himself. One goal of this being to put together a PDP-11 system that could be more easily taken to vintage computer shows than the ‘rollable’ PDP-11s he had access to prior. Of 1980s PDP-11s, the first-generation Large Scale Integration (LSI) PDP11/03 system (so-called Q-Bus models) is among the smallest, taking up about as much space as a 1980s desktop PC, while supporting the second generation LSI PDP-11/23 cards. It all seemed so easy until [David] tried testing the PDP-11/03’s PSU and everything went south.

Despite having access to the circuit diagrams of the PSU, figuring out what was going wrong was an absolute nightmare for [David], after some easy fixes involving replacing a blown fuse and bulging capacitors failed to deliver salvation. Reading through the comments to the video, it would seem that people are generally confused about whether this PSU is a linear, switching or some other configuration. What is clear is that with the absolutely massive transformer, it looks more like a linear power supply, but with a lot of protections against over current and other failure modes built-in, all of which rely on transistors and other components that could have gone bad.

Although in round 1 the PDP-11/03 PSU won the battle, we hope that once round 2 commences [David] will have had the proverbial training montage behind him (set to ‘Eye of the Usagi’, probably) and will manage to get this PSU working once more.

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Reverse-Engineering The ESP32’s WiFi Binary Blob With A Faraday Cage

January 15, 2024 by Maya Posch 37 Comments

The Faraday cage constructed by Jasper Devreker.

As part of a team reverse-engineering the binary blob driver for the ESP32’s WiFi feature at Ghent University, [Jasper Devreker] saw himself faced with the need to better isolate the network packets coming from the ESP32-under-test. This is a tough call in today’s WiFi and 2.4 GHz flooded airwaves. To eliminate all this noise, [Jasper] had to build a Faraday cage, but ideally without racking up a massive invoice and/or relying on second-hand parts scavenged from eBay.

We previously reported on this reverse-engineering project, which has since seen an update. Although progress has been made, filtering out just the packets they were interested in was a big challenge. The solution was a Faraday cage, but on a tight budget.

Rather than relying on exotic power filters, [Jasper] put a battery inside a Faraday cage he constructed out of wood and conductive fabric. To get Ethernet data in and out, a fiber link was used inside a copper tube. Initial testing was done using a Raspberry Pi running usbip and a WiFi dongle. The Faraday cage provided enough attenuation that the dongle couldn’t pick up any external WiFi signals in listening mode.

The total cost of this build came down to a hair over €291, which makes it feasible for a lot of RF experiments by hobbyists and others. We wish [Jasper] and the rest of the team a lot of luck in figuring out the remaining secrets of Espressif’s binary WiFi blob using this new tool.

Haiku OS: The Open Source BeOS You Can Daily Drive In 2024

January 15, 2024 by Maya Posch 25 Comments

Haiku is one of those open source operating systems that seem to be both exceedingly well-known while flying completely under the radar. Part of this is probably due to it being an open source version and continuation of the Be Operating System (BeOS). Despite its strong feature set in the 1990s, BeOS never got much love in the wider computer market. Nevertheless, it has a strong community that after twenty-two years of development has now reached a point where you can daily drive it, according to the [Action Retro] channel on YouTube.

One point where Haiku definitely scores points is with the super-fast installation and boot. [Action Retro] demonstrates this on real hardware, and we can confirm that it boots very fast in VirtualBox on a low-end Intel N100-based host system as well. With the recently introduced QtWebEngine-based Falkon browser (formerly known as QupZilla) even JavaScript-heavy sites like YouTube and retro Mac emulators work well. You can even get a Minecraft client for Haiku.

Although [Action Retro] notes that 3D acceleration is still a work-in-progress for Haiku, his 2014-era AMD system smoothly played back 1080p YouTube videos. Although not addressed in the video, Haiku is relatively easy to port existing software to, as it is POSIX-compatible. There is a relatively modern GCC 11.2 compiler in the Beta 4 release from 2022, backed up by solid API documentation. Who doesn’t want to take a poke at a modern take on the OS that nearly became MacOS?

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Why The IPad Doesn’t Have A Calculator

January 14, 2024 by Maya Posch 78 Comments

For the handful among us who have an iPad tablet from Apple, some may have figured out by now that it lacks a feature that has come standard on any operating system since roughly the early 90s: a calculator application. Its absence on the iPad’s iPadOS is strange since the iPhones (iOS) have always had a calculator application built into the system. Even Apple’s laptop and desktop systems (MacOS/OS X/MacOS) include a calculator. As [Greg] at [Apple Explained] explains in a 2021 video, this seems to have been initially due to Steve Jobs, who didn’t like the scaled-up iOS calculator that the person in charge of iPad software development – [Scott Forstal] – was working on and set an ultimatum to replace or drop it.

In the video, [Greg] shows sections of an interview with Apple software chief [Craig Federighi], who when confronted with the question of why iPadOS doesn’t have a calculator or weather app, quickly slithers out of the way of the incoming question. He excuses the absence with the idea that Apple won’t do anything unless it makes people go ‘wow’ when they use it. Fast-forward two years, and iPadOS 17 still doesn’t have a version of the Apple Calculator app, making for rich meme fodder. One question that gets raised by some is whether Apple really needs to make such an app at all since you can use Spotlight and Siri to get calculations resolved, in the latter case, using the apparently hidden Calculator app.

These days, you can use Google Search as a calculator, too, with it even throwing up a calculator UI when you ask it to perform a calculation, and the App Store is full of various calculator apps, with or without advertising and/or paid features. In this context, what could Apple do with a calculator that would positively ‘wow’ its users?

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Wiring An SD Card To A Handspring PDA’s 68K Bus With Only Three SOT23s

January 13, 2024 by Maya Posch 13 Comments

In 1998 the founders of Palm had a bit of a falling out with the wildly successful PDA company’s new owners. They set up a new company called Handspring, which enabled them to make PDAs again in the way they preferred, This resulted in the Handspring Visor line of PDAs, which featured a big cartridge slot called the Springboard Expansion slot. Much like a Gameboy, you could put in a range of modules, ranging from games to cameras to memory expansion and more. Since these modules connect directly to the internal Motorola 68k-based microprocessor, you could make a module either to comply with this standard or if you’re like [Dmitry], you’d figure out a way to get an SPI device like an SD card to communicate and expand storage.

Editor note: Dmitry’s design isn’t the first SD/MMC interface for the Visor. Portable Innovation Technology’s SD MemPlug Module supported SD/MMC way back in 2002. However – MemPlug was a commercial product, while Dmitry’s work is open source.

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TMS 1000 Microcontroller - By Antonio Martí Campoy - Own work, CC BY-SA 4.0

The Early History Of The Microcontroller: It Came From Texas

January 12, 2024 by Maya Posch 17 Comments

Ti’s presentation of the rapid integration of calculator chips.

Although for most generations alive today the era of microcontrollers (MCU) feels like it starts somewhere with the Intel 8051 and AVR MCUs, the history of these self-contained computing marvels that are now found just about anywhere begins long before those were even conceptualized. In a recent article titled Tiny Computers From Texas, [Babbage] goes through this early history of what would ultimately become such an integral part of daily life.

An MCU is defined as a small, self-contained computer, which requires few to no external components to function. This contrasted with the more traditional MPUs, or microprocessor units, where a computer was assembled out of one or more MPUs, I/O chips, memory SRAM and so on. It’s perhaps little surprise that the drive towards MCUs was the result of primarily the calculator market, where competing firms were trying to upstage each other with higher levels of integration into as few chips as possible, while driving down costs and power usage.

Ultimately, the Texas Instruments TMS 1000 was the first true MCU that got produced in large volumes after its release in 1974. Moving beyond calculators, the TMS 1000 found its way into toys, including the Speak & Spell – which uses another Ti chip (TMS 5100) for the voice synthesis – so that today any toy can be interactive in exciting and often noisy ways.

Back in 2020 we took our own affectionate look at this chip.

Bambu Lab To Allow Installing Open Firmware After Signing Waiver

January 12, 2024 by Maya Posch 26 Comments

On January 10th Bambu Lab published a blog post in which they address the issue of installing custom firmware on your Bambu Lab X1 3D printer. This comes hot on the heels of a number of YouTube channels for the first time showing off the X1Plus firmware that a number of X1 users have been working on as an open source alternative to the closed, proprietary firmware. Per the Bambu Lab blog post, there is good and bad news for those wanting to use X1Plus and similar projects that may pop up in the future.

After Bambu Lab consulted with the people behind X1Plus it was decided that X1 users would be provided with the opportunity to install such firmware without complaints from Bambu Lab. They would however have to sign a waiver that declares that they agree to relinquish their rights to warranty and support with the printer. Although some details are left somewhat vague in the blog post, it appears that after signing this waiver, and with the target X1 printer known to Bambu Lab, it will have a special firmware update (‘Firmware R’) made available for it.

This special firmware then allows for third-party firmware to be installed, with the ability to revert to OEM firmware later on. The original exploit in pre-v1.7.1 firmware will also no longer be used by X1Plus. Hopefully Bambu Lab will soon clarify the remaining questions, as reading the Reddit discussion on the blog post makes it clear that many statements can be interpreted in a variety of ways, including whether or not this ‘Firmware R’ is a one-time offer only, or will remain available forever.

It’s not the first time we’ve seen a 3D printer manufacturer give users this sort of firmware ultimatum. Back in 2019 Prusa added a physical “appendix” to their new 32-bit control board that the user would have to snap off before they could install an unsigned firmware, which the company said signified the user was willing to waive their warranty for the privilege.

Thanks to [Aaron] for the tip.