I would like to show you the last Z80 computer ever made, at least for some definition of
computer.
And for some definition of made.
Because the 80 computers are still being made today, you can get one for one hundred
per a few euros from Amazon.
And it will be shipped tomorrow for free.
But the only reason this is using a Z80 is for compatibility reasons with a long family
of previous machines that stretches back to the late 80s.
So if they build this today, they would probably use ARM or X5.
So that's not what I have in mind.
And of course, you can also find the Z80 in embedded systems.
And in hobby machines made for fans of retro computer.
So for people like you.
So again, that's not really what I would like to talk about.
What I really want to know is when was the last time that somebody sat down to design a completely new computer
and he tectr for the general public.
So not for you.
And he decided that the Z80 was the best match for it.
So I asked tragedy.
And it showed me this.
Which is a nice guess.
But of course, tragedy is wrong.
Because two years later, we got a nice Z80 based pound-top, for example.
And yet, two years after that, we got this.
A sweet call mail station.
And this is the last Z80 based architecture that I was able to find.
So what is the mail station?
Well, in the 90s, there was a choice to build the built machines that were labeled as
internet appliances to make connecting to the internet easier.
If you ever wanted to go online on Windows 95, you know that it's, let's say, not very easy.
So for many people, it was a standing block to go online and use the web or the email.
So many companies built specialized appliances that let you just plug it in,
turn it on, and it would work.
So the official slogan through the main station was email made easy.
You just plug the machine into your phone line.
You turn it on, it would dial to the ESP phone number and you could send and receive emails.
For some reason, they renamed it very quickly to email without a PC.
So I guess that was not that easy after all.
But that's the main station.
And if you look at the hardware specs, it has a blazing fast Z80 processor running at 20 megahertz.
A lot of memory, a modem, and it has even a printer port.
So you could not only read your emails on the screen, but actually print them out.
And it will prove very useful in a few minutes.
So because it's a specialized machine, it stretches a little bit the definition of a computer.
But at least for me, if it works like a computer and it works like a computer, then probably it's a computer.
And the most important reason why I think so is that because it can run custom applications.
So you are not limited just to the email sending receiving firmware that's on the machine, but you can also run your code on it.
And if you can run application, then of course you can hack the machine.
And that's the most important thing you do with the computer.
Let's do it.
First, I would like to show you the official method of running applications on this machine.
If you power it on, you can see a little Yahoo icon.
And if you choose this many options, you get a list of various information channels.
In this case, these are top stories and TV types.
Also subscribe to weather forecasts, stock quotes, horoscopes, these kind of things.
And this would be updated on your machine every day.
So if you choose top stories, for example, this is what you get.
Because it's an American machine or the top stories about mass shootings.
And you would think that this is some kind of America language that is used to display this information on your screen, but it's not.
It's a bit map.
And those top stories icon that you just clicked is an application written in the 80 assembly code that displays this bit map on your screen.
So you could have any kind of application written and you could just run it the same way.
So the way it works is if you subscribe to an information channel, Yahoo sends you an email every day with an updated application.
Your computer downloads this email and without telling you, it does not put it in your inbox, but it just extracts the application and puts it in the Yahoo folder.
And this application can run any Z80 codes.
And it because it's as 80, that's of course no memory protection.
So as you should know, the first rule of image security is do not open unknown attachments.
But it does not apply to the main station because in the main station, you don't open the attachments, the computer opens them for you.
So of course, the creators of the machine thought about some security issues.
So there is some kind of checksum that must be correct in order for all these to work.
So they even find a patent where you can read about all these.
So I was not really familiar with this simple desk version of encryption.
So I asked John GPT how easy it would be to crack it.
And the answer was not very much.
So what you could do?
What you could do is write your application and send yourself 1224 emails with different checksums.
And one of them is guaranteed to work.
There's only one tiny little problem here.
You would need to have an email account configured on your station.
And if you try to do that, you may get the screen.
So I called this number.
And I was put on hold.
It was half an hour of my life that I will never get back.
And finally I learned that support for the main station stopped about 20 years ago.
So the dial-up numbers don't work.
The servers don't exist anymore.
They will not configure the email address for me.
But don't worry, we are not done yet.
When the machines were released to the market, some enterprising hacker disordered the wrong sheep from the mainboards.
And when it analyzes, he found those ASCII strings.
So those strings suggest that there is some way to update the software on the machine.
So a couple of guys got together and they started analyzing the code around those strings.
And they came up with nice diagrams that show how the code works.
It's really easy to follow and there's just 10 pages of it.
So if you look at the diagrams and analyze how they work, it's basically this.
And the one ever used one of those?
Yeah.
Yeah, exactly.
So the main station has a pointer port, right?
And a smart company named LappLink came up with a way to use a pointer port for bi-directional configuration.
Because in addition to the data bits, the pointer port has also some lines to which status back from the pointer later.
The pointer is busy, the pointer is out of paper, the pointer is on fire.
So if you cross-connect those status bits with data bits, you can send data back and forth.
So using this kind of cable, you can upgrade the firmware on the main station.
So I wrote a short program, which does exactly that.
The only tiny little problem is that you need to upgrade the whole one megabyte of firmware.
So even if you write a tiny change to some tiny function in the wrong, you still need to upload the whole one megabyte through the cable.
And if something wrong happens in the middle of this process, you get a breakdown of the station.
Trust me, I should know.
So is there an easier way to do it?
Well, there is.
At least for some definition of easier.
If you power on your station and press a secret key combination, you will get a nice diagnostic mini, which asks you to choose one of the six options.
Don't do that, of course.
But press another secret key combination.
And you will get a hex viewer, which allows you to view the contents of the flash chip that holds all the user data and settings.
And using yet another secret combination,
turns the hex viewer into a hex editor.
So you can write your application and enter the hex decimal codes for all the bytes in your app in the editor and then you can run it.
But if for some reason you don't want to do that, you can use that instead.
This is called a stage one loader.
It's a program that's 64 bytes long.
And because the main station film already has the ladling transfer routines built in, it uses the existing ROM to download and execute the program from the PC.
So all you ever need to do is to enter those 64 bytes into your machine and you're done.
And then you can upload a stage 2 loader, which is a very nice mini-driven application that allows you to upload and download data from the main station.
And then you have hacked it.
So what have people done with the machine so far?
Well, of course, because it has a more than somebody built a nice application that allows you to dial into your local BBS and interact with it.
And if you don't like the modem, that's also why if I want to do it, that's somebody built.
And of course, since it's a Z80 machine, you would like to run CPM on it, which is unfortunately not that easy because it has ROM at the bottom of the memory map.
So somebody built a hardware modification to put RAM there instead.
And then he wrote a nice CPM BIOS and he wrote, I think, something like that.
Okay, so these are some of the projects that I find on the internet.
But the most important project has not been written yet.
And maybe you are the one who's going to write it.
If you want to do that, I created a main station function library, which allows you to interact with some such hardware functions as screen keyboard timers, interrupts, modems, stuff like that.
We added some more resources, so there's an emulator here as well.
It's pretty basic, but it works, so you don't really need an actual machine.
You can write your code and run it in the emulator.
There are some sample codes, libraries, documentation, data sheets.
All you ever need to hack the main station is here.
But I also have those two boxes here with me.
And each box contains a main station.
We've staged to loader already installed, so you don't ever need to use the hex editor.
A U of P on the power supply, a lapling cable, and my email address.
So if you want to get your hands on a Z80 machine and do some hacking, find me after the talk, and one of those boxes will be yours.
Otherwise, thank you very much.
I'm for questions.
We have one here.
How many did you break?
Three.
Three broken and he still has two to give away.
And I still have eight at home, so.
How the graphics work is it just a framework?
It's just a framework, yes.
Have anyone wrote a demo, demo scene demos?
There are some applications in the GitHub repository that draw a bit up on the screen, for example.
So you could count it as kind of demo, I guess.
Maybe you can write about the one.
Okay, over here.
Can I have sound or can I convert modern port to make sound or something?
I tried that.
I haven't had success so far.
So yes, there is a modern chip and there is a speaker.
And from the data sheet of the modern chip, I concluded that it is possible to play some wave sounds.
But so far, I was unlucky in that.
So it could be done probably, but I can't be 100% sure.
Double question.
What if I tried to refresh the firmware on one of the broken consoles?
And does it run doom?
Okay, number two, not yet.
That is a matter of time, of course.
Number one, if you break your main station, it means that the code, on the main station side,
used to download the firmware is not working anymore.
So you can't re-flash a briefed my station.
What you can do, of course, is to disolder the wrong chip.
Use your eProm programmer to reprogram properly and then solder it back.
Some people have reported success with doing that.
You have time for one very short question, and I can ask a question of to come up to the front.
Test somebody over there, I think.
Where the system updates, cryptographically secured, or was it SDS again?
Now, there are not cryptographically secure.
You just push bites to the machine.
Okay, thumbs up. May thanks, Michel.
Thank you very much.