An Amstrad PCW Receives A Bit Of Love

April 6, 2025 by 6 Comments

If Clive Sinclair’s genius in consumer electronics was in using ingenious hacks to make cheaper parts do greater things, then his Amstrad competitor Alan Sugar’s was in selling decade-old technology to consumers as new and exciting. His PCW series of computers are a great example, 1970s CP/M machines smartly marketed for late 1980s home offices. They were a popular choice at the time, and [Retro Recipes] has one. In  a video filmed in period standard definition he’s taking us through a repair to its Gotek drive, and then a RAM upgrade.

The repair and upgrade are fairly straightforward, the former being a failed OLED screen on the drive and the latter being the installation of a bank of DIP memory chips. The interest lies in how they cost-minimised a CP/M machine as a consumer product. The board relies heavily on custom chips as you might expect, and there’s a brief glimpse of one of those unusual 3″ floppy drives. The power supply is part of the monitor board as was often the case with Amstrad machines, and the whole thing is about as simple as it can be. The full video can be found below the break.

We’re guessing that particularly in the UK there will be plenty of PCWs still languishing in dusty attics, but surprisingly given their popularity at the time we see less of them that might be expected. There has been a significantly upgraded model on these pages though.

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Emulating IPhone On QEMU

April 6, 2025 by 3 Comments

[Georges Gagnerot] has been trying to emulate iOS and run iPhone software in a virtual environment. There were a few choices, and qemu-t8030 had a number of interesting features that you can check out in his post.

The project requires a patched QEMU, and [Georges] did some basic jailbreaking techniques. The real problem, of course, was not having the Apple Silicon GPU. Older versions of iOS let you select software rendering, but that option is gone on newer versions. However, it was possible to patch the phone to still use software rendering. There are still apps that directly use Metal or OpenGL that won’t run, but that’s another problem.

There is a plan to explore forwarding GPU calls to a real device. However, that seems difficult so it will have to wait for now.

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Celebrating 30 Years Of Windows 95 At VCF

April 6, 2025 by 78 Comments

It’s been 30 years since Windows 95 launched. [Ms-Dos5] and [Commodore Z] are celebrating with an epic exhibit at Vintage Computer Festival East 2025. They had no fewer than nine computers — all period-correct machines running versions of Windows 95. The pictures don’t do it justice, so if you are near Wall, NJ, on Sunday, April 5, 2025, definitely go check out this and the rest of the exhibits at VCF.

An exhibit like this isn’t thrown together overnight.  [Commodore Z] and [Ms-Dos5] worked for months to assemble the right mix of desktops, laptops, and peripherals to showcase Windows 95. Many of the computers are networked as well – which was no easy task.

One particular Thinkpad 760e required pliers and force to remove a stuck PCMCIA modem card. After a struggle that was ultimately destructive to the card, the pair determined it was stuck due to a sticker that had effectively glued the card into the laptop. As the sticker finally gave up, the card popped itself out of the laptop.

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A Low F Number Lens, From Scratch

April 6, 2025 by 52 Comments

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length. Lenses with low F-numbers are prized by photographers for their properties, but are usually expensive because making a good one can be something of a challenge. Nevertheless [Rulof] is giving it a go, making an 80mm F0.5 lens with a Sony E-mount. The video below the break has all the details, and also serves as a fascinating primer on lens design if you are interested.

Rather than taking individual lenses, he’s starting with the second-hand lens from an old projector. It’s got the required huge aperture, but it’s by no means a photographic lens. An interesting component is his choice of diaphragm for the variable aperture, it’s a drafting aid for drawing circles which closely resembles a photographic part. This is coupled with the triplet from an old SLR lens in a 3D-printed enclosure, and the result is a lens that works even if it may not be the best. We know from experiences playing with lens systems that adjusting the various components of a compound lens like this one can be very difficult; we can see it has the much sought-after bokeh or blurred background, but it lacks sharpness.

Perhaps because a camera is an expensive purchase, we don’t see as much of this kind of hacking as we’d like. That’s not to say that lenses don’t sometimes make their way here.

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Ben Eater Vs. Microsoft BASIC

April 5, 2025 by 12 Comments

[Ben Eater]’s breadboard 6502 computer is no stranger to these parts, so it was a bit of a surprise that when [Mark] wrote in asking us if we’d covered [Ben]’s getting MS BASIC running on the breadboard, that our answer was “no”. Well, that changes today!

This is a three-part video series, documenting how [Ben Eater] ports a 1977 version of MS BASIC to his 6502-based computer. The first video is all about just getting the BASIC up and working. It’s full of detail about how MS BASIC adapts to different architectures on the inside, and [Ben] essentially defines his own along the way.

Once he has BASIC working, the next two videos are about making it work not just with the serial terminal that he has attached, but also with the LCD display peripheral he has plugged into the breadboard. BASIC fans will not be surprised to see that it’s all about using POKE. But that ends up being to slow, so he extends it out with his own LCDPRINT command written in assembly.

Now that he can write a character to the LCD, he wants to be able to pass it a string: LCDPRINT “Hello world”. But that requires his command to be able to parse a string, and this has him diving down the rabbit hole into how MS BASIC parses strings, handles evals, and so on. If you want to know how MS BASIC works on the inside, this is the video for you. This video makes a lot of use of wozmon, which seems an almost ideal tool for this kind of low-level poking around.

All of this is done in [Ben]’s very well rehearsed, accessible, but pulling-no-punches style. Get ready to nerd out. All three of the videos are embedded just below the break.

While it’s not the Altair BASIC that Bill himself was writing about last week, it’s probably a direct descendent, and reading about the Altair version was what spurred [Mark Stevens] to send us the tip. Thanks!

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Inside An Edison Phonograph

April 5, 2025 by 14 Comments

If you think of records as platters, you are of a certain age. If you don’t remember records at all, you are even younger. But there was a time when audio records were not flat — they were drums, which was how the original Edison phonograph worked. [Our Own Devices] did a video earlier showing one of these devices, but since it was in a museum, he didn’t get to open it up. Lucky for us, he now has one of his own, and we get to see inside in the video below.

Ironically, Edison was deaf yet still invented the phonograph. While he did create the working phonograph — his self-identified most important invention — the original invention wasn’t commercially viable. You could record and playback audio on tin foil wrapped around a drum. But you couldn’t remove the foil without destroying it.

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How Shrinking Feature Size Made Modern Wireless Work

April 5, 2025 by 4 Comments

If you’re living your life right, you probably know what as MOSFET is. But do you know the MESFET? They are like the faster, uninsulated, Schottky version of a MOSFET, and they used to rule the roost in radio-frequency (RF) silicon. But if you’re like us, and you have never heard of a MESFET, then give this phenomenal video by [Asianometry] a watch. In it, among other things, he explains how the shrinking feature size in CMOS made RF chips cheap, which brought you the modern cellphone as we know it.

MESFET
MOSFET

The basic overview is that in the 1960s, most high-frequency stuff had to be done with discrete parts because the bipolar-junction semiconductors of the time were just too slow. At this time, MOSFETs were just becoming manufacturable, but were even slower still. The MESFET, without its insulating oxide layer between the metal and the silicon, had less capacitance, and switched faster. When silicon feature sizes got small enough that you could do gigahertz work with them, the MESFET was the tech of choice.

As late as the 1980s, you’d find MESFETs in radio devices. At this time, the feature size of the gates and the thickness of the oxide layer in MOSFETs kept them out of the game. But as CPU manufacturers pushed CMOS features smaller, not only did we get chips like the 8086 and 80386, two of Intel’s earliest CMOS designs, but the tech started getting fast enough for RF. And the world never looked back.

If you’re interested in the history of the modern monolithic RF ICs, definitely give the 18-minute video a watch. (You can skip the first three or so if you’re already a radio head.) If you just want to build some radio circuits, this fantastic talk from [Michael Ossmann] at the first-ever Supercon will make you an RF design hero. His secrets? Among them, making the most of exactly these modern everything-in-one-chip RF ICs so that you don’t have to think about that side of things too hard.

Thanks [Stephen] for the tip!

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