I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now, I'm going to go right now,
I'm going to go right now, I'm going to go one by one, so lightly, lightly that you have to,
ever seen a 900 in person, I'm quite sure that you are familiar with this machine, which actually uses a video
cheap developed for the 900s. Sorry for the technical difficulties. The unique
machine itself is so rare that only two times in the whole history there was a
Commodore 900 sold on eBay. And one of them was bought by me. So in 2014 I acquired this
beautiful work station with no keyboard, no mouse, no screen, no software, entered
already didn't power on as well. So since I have only 15 minutes today I cannot
tell you everything I did to make the machine work but this is what I wanted to show
you. When I finally was able to turn it on I saw that it was trying to load the
operating system from the hard drive and showing me a very helpful and informative
message saying start to sff. So what the f is start to sff. There's no mention of it in
the documentation. So after scratching my head for some time I realized that the only
way to find out was to disassemble the boot ROM and try to understand what
this is doing. So anyone here ever programmed the Z8000. Me neither. So I had to learn
and after going through approximately 300 pages of this I found the place where the
computer was trying to access the disk and it works like this. It places a
common to the disk controller into the memory and the disk controller is supposed to
override the status byte with its response. So if the status is still ff it means
the disk controller never responded at all. Why? Maybe it's broken. So I thought if I
can replace the disk controller maybe I could make the machine work but the problem was
when I entered the disk controller name into Google I got zero results. Nothing.
Today if you entered the disk controller name into Google you will get many
results but all of them are me asking for help on different forms.
So turns out this controller is completely custom made just for this machine so I can't
replace it. So if I can replace it maybe I can fix it. So I started examining the
disk controller board and I found the broken chip. So I was so happy for about two minutes
and the output the machine on and I so didn't know it was still giving me the same
error. So I replaced some other chips on the board. Nope. So the same error. So we flash
the micro controller on the board. Nope. Still the same error. So I thought okay maybe
I will disassemble the firmware of the micro controller and they I will understand what
it's doing and why it's not responding. Yeah anyone here programmed the Intel 8048?
You did. You have my condolences. It's a very old and very primitive micro controller
from the 70s. So after going through the disassembly for many days I still had no idea
what the code was doing. But fortunately I found an ASCII string with the copyright note
and the name of the developer who will the firmware. So I found the guy. Yeah so I found
the guy only to in and sent him a message asking for help. And he never replied me back.
So I was on my own and I thought okay maybe that this controller is not broken. Maybe
the disk is broken. So I bought the identical hard drive and headed shipped from United
States and nope still the same error. So I bought a completely different hard drive and headed
shipped from United States and wonder of wonders. I saw a different error message. So instead
of status FF the computer was now turning me bedfile type. Any probablin means that the computer
does not understand the file system that's on the disk. But it also means that this controller
works and the disk works and the computer can read data from the disk. So how is it possible
that a completely random drive from eBay works and the original one doesn't. The replacement
for the original also doesn't. Well if you go back to the second slide that I showed you it
is MFM hard drive and MFM hard drives needs to be low level format it before you use them.
So by pure luck I was able to buy a disk that was format it in the same way that my disk
controller wanted. And the original disk was not format it. So the computer couldn't use it and instead
of giving me a proper error message that this controller just went and infinite loop trying
to find a sector on an unformatted disk. So maybe it's a good thing that the firmware guide did
not respond to me because now I had a thing or true to say to him about a proper error error.
But okay I had a disk now but unfortunately after playing with the disk some more it turned out
that every 17th sector was still giving me a error FF. Why? Well 17 turns out so be exactly
the number of sectors per truck. And since this is a disk that came most likely from a PC
if you format a disk on a PC the sectors are numbered from one. But this is a unique machine so
maybe it needs a sector to be numbered properly starting from zero. So I had to reformat the
disk anyway. So I went back to the guide that sold me the hard disk and I thought hey I bought
the hard disk from you can you tell me which controller you use with it so I can buy it as well
and use it to reformat it with different sector number. And he was like that's a method just
format it in your old machine and I said I can't format it in my own machine because I do know
how. So just tell me which controller you use and then I will try to use it as well. And he was like
that's a method just format it in your own machine. Just going back and forth like this a few times
as I said finally okay I am going to format in my machine. So how can I do that? Well this screen tells
you press any key twice. Don't do that. Instead if you press one and the nine you will go into
a machine language monitor and a machine language monitor allows you to put data into the memory and
like I told you this is exactly the way you communicate with the disk controller. So I could use it
to send a format disk commands to the controller and the only tiny little problem is this comment
is not implemented. So now I really had a few things to say to the firmware guide but I thought okay
they they had to be a way to format the disk somehow right. So I went back to the firmware
this assembly and I found out that okay there is no format disk commands but there is a format track
comment. So I could enter comments to format individual tracks one by one and there are only 2600 tracks
on the disk. So if I started in 2014 I would probably be finishing a run now. So how can I do
it better? Well this is a unique server right? So how do you access a unique server? Today you
would access it over a network in 1985 you access it over a terminal. So if I could attach a PC
and make it act as a terminal and pretend that I'm typing all those track formatting commands
I could make it work and this is the program that does exactly that.
So now I had a properly formatted disk I was ready to put software on it software that I didn't have.
But fortunately there are images of the installation floppy on the internet. So I could download
the images and make the floppy. How do I make the floppy? Well the images are 1.2 megabytes
inside. Inside the floppy is a 5 inch. So maybe I could just make them on a PC right?
Now it turns out I can't because it's Commodore and Commodore uses a different disk encoding than
everybody else. So maybe I could get a Commodore disk drive from the Commodore pads that also
uses GCR encoding and use this one to make the floppy. One turns out I can't because it's Commodore
but unique Commodore. So the sextos are bigger than on the 8 bit machines. So maybe I could hack
a Commodore floppy drive to use bigger sectors. Noters like I can't because the track density
is different as well. So at this point I was like really guys. So in the end what I had to do
was to go back to my disk formatting program and modify it so that it puts data for every
sector into the computer memory and issues the sector right comments to the floppy controller.
And it took this way it took only 18 hours to make one floppy.
Provided that there was no arrow in the middle. So after a week or so I had this beautiful set
of installation floppy. I could use to put the system on my properly formatted hard drive.
And when I did that this is what I got.
And if you look at this photo carefully you will see that the root account has no password.
So apparently that's how you use the Unix in 1985. Thank you very much for your attention.
Thank you.
I have been in touch with the guy from the Richard Lane Cave channel, because I'm going
on 100 times 10 as well.
I haven't been in touch with the guy from the YouTube channel, what's the name of the channel?
Richard Lane Cave, I have seen the video, but I have not been in touch with him.
He made the video recently, and I did this like 11 years ago.
So no, no, I haven't.
How did I celebrate? I'd rather not say.
Sorry?
Possibly?
Great folks for how are you doing?
When you finally got the floppy image, we installed the system through your already pop at the top right.
Unfortunately, no, it turns out that the system installation disks already assumed that your hard drive is formatted.
So there are rumors that there exist a floppy format in software somewhere in Austria, but I haven't been able to verify the rumors.
I have been in touch with the guy from the Richard Lane Cave channel.