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Hello 8bit'ers,

this email in your inbox is the perfect indicator - it's Friday. That means, tomorrow the weekend just starts. And it is therefore the perfect time to celebrate the birthday of the ZX Spectrum.

Birthdays happen on average every 365 days, but this one is a special one, because it's the 40th. That's why we're a little Speccy-heavy in this issue. But we also found additional topics this week, which are quite worth their money. 

Judge yourself and enjoy Issue #47.

PS: There won’t be an issue next week, we’ll touch down in your inbox May 13th again.


Pico Speccy

Pico Speccy
Imagesource: Bill Bertram - Wikipedia - CC BY-SA 2.5

So many birthdays every year. And every year we celebrate again. But this birthday is special, because it's the 40th. And of course it is the birthday - better release date - of the ZX Spectrum. 🎉

Actually, you're not old when you're 40. As they say, the first 40 years of childhood are the best after all. 😁

And so the litte machine - affectionately named Speccy - has a huge fan base to this day, still producing new hardware and software for this masterpiece from Sir Clive Sinclair.

Since this week's focus is on the little 8-bit'er, we join the queue, and provide a few of the gems of this week. First up is Peter Misenko with his Pocket ZX Spectrum. The info on Hackaday is a bit thin, currently you can only become Peter's Patreon, to get access to the PCBs. It actually is a Raspberry Pi Pico based home-brew, in a very handy format.

If that’s your thing and if you would like to build your own Pico, you find more info in our Issue #17. There we had already reviewed the first version of the device. But in this issue it is of course a perfect fit. 

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Z80 Debugger

DeZog - Z80 Debugger
Imagesource: https://github.com/maziac/

To play or work with the Speccy is one thing. (Certainly an interesting one.) But it becomes really exciting when you want to implement real-world requirements on the Z80 CPU of the machine in Assembly itself.

"Does anyone do that anymore" I hear you say? The Z80 is still in production today, That answers the question. Once you warm up to the way the Z80 Assembly works, you'll have real fun with the thing. But the fun also ends very quickly, when you have to distribute coding, assembling, debugging, disassembling, sprite conversion and all other tasks over a whole bunch of different applications. 

The unfortunately unknown author maziak has recognized this problem, and has a solution for it.

DeZog will probably be known to pretty much everyone, who gives the Speccy a proper Assembly treatment.

But for those who don't know it yet, DeZog is a real enlightenment. The VSCode extension has a lot to offer. As a debugger it fulfills all expectations. Standard debugging as you know it, sprite display, performance measurement, disassembly of existing object code, display of registers, stack and callstack ...

If you program for the Z80, you can't get around this piece of software. Prerequisite: VSCode.

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ZX Spectrum Mixtape

ZX Spectrum Mixtape
Imagesource: https://itch.io/b/1343/

And one last one for the Spectrum. Quantum Sheep has compiled 40 current software titles on a Mixtape, to celebrate the machine's birthday. 

30 creators contributed, and the total price of $10.00 is a real bargain. Honestly, this bundle might be a good reason to buy or switch to the little, black plastic box.

Check it out for yourself. As always with commercial products, we are not sponsored, just think the project is worth supporting.

Have a look.

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Frog Find

Frog Find
Imagesource: http://frogfind.com/

Frog Find is a really cool idea from Sean aka Action Retro

The problem: You have a machine that has slightly gray and thin hair, but is far from being old-fashioned. The box even connects to the Interwebs, and has a browser. But it's so old that you can hardly open any modern website in a meaningful way?

This is exactly where Frog Find kicks in. The search engine is a wrapper for DuckDuckGo, acts as a proxy and translates modern Markup and CSS into very simple HTML, with which even browsers from the stone age should be able to cope. Websites that are otherwise not displayable on aging devices get a second chance this way.

Best of all: Thanks to modern technologies from the future, 8bitnews also renders server-side, and can thus be read on vintage machines thanks to Frog Find.

A dream! Thanks Sean.

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NT Gameboy

Windows NT Gameboy
Imagesource: https://unsplash.com/

If someone has a correct and concrete definition for retrocomputing, then please ping me. Are we simply talking about age? If so, Windows NT doesn't count in my time calculation. Neither does the Gameboy, which turned 33 a few days ago.

But what if you combine the two? Doesn't make sense? Oh yes, it does!

Thanks to a hint from netzherpes we became aware of the side project of oerg866 this week. And it's about just that - a Gameboy emulator for Windows NT - mercyboy.

Build targets besides NT are (buckle up) Windows95 and DOS. 14 games including Super Mario Land 1 & 2 have already been tested by oerg866, probably more should run. There are minor problems, but a perfect emulation is not the primary goal for implementations in this state.

What counts is to emulate one of the most popular gaming machines of its time on one of the most popular Microsoft operating systems of the same era. The primary ISA alone has 245 instructions that want to be emulated. And that's not the end of the story.

Very special, but definitely a project for a few weekends or even a few more. Great work.

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C64 Engineers’ Story

Commodore 64 Engineers' Story
Imagesource: https://spectrum.ieee.org/

Tekla Perry and Paul Wallich are always a guarantee for excellently researched stories about retro technology topics. And since this year beside the ZX Spectrum also the C64 will celebrate its 40th, the two dug deep in the history of the machine.

Instead of generic and well-known facts, their article on spectrum.ieee.org features the engineering background of the breadbin that, among other 8-bit machines, brought microcomputers into the homes of the 80s. If you have a little sense of history and interest in technology, the article is definitely a recommendation.

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New CPU Features

New CPU Features
Imagesource: https://unsplash.com/

The charm of CPUs from the 70s and 80s is partially based on the fact that besides the instruction set, the implementation model of these transistor collections can still be understood by a single person. For everything constructed after the end of the 90’s, this is no longer the case in my opinion. And please raise your arm, who knows every single mnemonic or even the majority of them of the x86 architecture.

Fact is, since the design of the first really successful 8-bit CPUs in the mid-70s, a lot has happened in the field of CPU design and optimization. And everything that humans can't explain on the basis of their own knowledge, seems sufficiently like magic. In order to demystify exactly that, Dan Luu has dealt with the architectural CPU features, that represent the delta between the 8-bit dwarfs and modern 64-bit bolides.

For those, who like to send electrons through only few atoms thick wires with the help of their own designs, Dan's article is the perfect reference and a treasure chest filled with additional resources to deepen your knowledge. And if you're feeling spurred on now, there's another excellent video by Matt Godbolt on x86 ISA in our Fun section below.

Have fun.

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Before Calculators

Why Sliderules matter
Imagesource: https://unsplash.com/

Sometimes you have to look beyond your own nose. And sometimes it helps to look back to the past to get a clearer view of the future. Likewise, every now and then we make the mistake of not ascribing knowledge and competence to generations before us to the extent that we should.

And even if the following topic is a completely analog one, and precision has to be replaced by approximation, the knowledge about it definitely makes a good addition to the tool belt of a modern software developer.

Besides, a real hoot for party nights ... or maybe not. Depends more on the audience, I guess. 🤓


Scott Locklin doesn't go into detail about their functionality, but rather why sliderules still have a definite reason to exist nowadays.

And without prejudice. Skilled calculation with a sliderule can be faster than with a calculator. Depends on the application. And accuracy to several decimal places is no problem, if you know what you are doing.

Maybe a pastime for cozy evenings and weekends, and in any case useful if you don't have 1200€ to spare for a Curta.

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DialUp Internet

DialUp Internet
Imagesource: https://youtu.be/Je8lwcUPBys

When I first saw a video stream over the Internet in 1997, it was as sensational as it was bad. The RealVideo codec was quite groundbreaking at the time, but connected via a 56k modem the video was the size of a postage stamp (the things one put on postcards in the past), and the blocks were so coarse, that you often had the impression of sitting in front of Chaos-Tetris.

56k transmission speed was state-of-the-art at that time, in Europe you could only get faster with ISDN or a 1MBit sync leased line from Telekom (the latter cost about 5000€ per month in Germany as far as I remember).

Anyway, DialUp technology is interesting. Therefore RetroBytes has decided to take a closer look at the topic, and in his current video he leads us through the technology itself, over terminals to the construction of your own ISP.

Informative and entertaining. Definitely worth checking it out.

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Mega65 Community Videos

Mega65 Community Videos
Imagesource: https://twitter.com/MEGA65Retro

In our very first issue we started with something big. The Mega65 that you most probably know. Ever since we touched the device here and there but never really dug into related videos.

That changed this week when we found the Mega65 Community Videos playlist from the Mega65 Team.

Unfortunately, the hardware is not a permanently available product, but can only ever be produced in pre-funded batches. The reason is, that the project is not designed for commercial success, and is driven by a number of enthusiasts in their spare time. But if you want to build your own Mega65, you can do so as well. We had all the info in Issue #24.

But if you just want to get a taste, you'll find more than enough material in the playlist.

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x86 Internals

x86 Internals
Imagesource: https://youtu.be/hgcNM-6wr34

As an addendum to the CPU History topic above, here's a clear recommendation on the x86 Instruction Set presented by Matt Godbolt.

The presentation is already a few years old, and the actual slides would make the talk shine, but even without them the following is really fun and super interesting.


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That was it again. We hope that the after-party headache of all Speccy fans will not last too long. But with the topics in this issue the suffering time on the weekend can be endured quite well. We hope that one or the other topic was included for you.

You have criticism or suggestions? Don’t wait. Just press the Reply button in your mail client form some sentences and press Send. You can reach us any time. 

And while you're at it, right next to the Reply button you'll find the one that says "Forward". Make your friends happy and just send them this issue directly. Everyone should be a little more 8-bit.

Have fun celebrating to all Speccy fans. Build something. And speak about it.

Take care.

Jan & Bastian

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