WEBVTT 00:00.000 --> 00:30.000 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, 00:30.000 --> 00:40.560 I'm going to go right now, I'm going to go one by one, so lightly, lightly that you have to, 00:40.560 --> 00:49.600 ever seen a 900 in person, I'm quite sure that you are familiar with this machine, which actually uses a video 00:49.600 --> 01:03.600 cheap developed for the 900s. Sorry for the technical difficulties. The unique 01:03.600 --> 01:10.960 machine itself is so rare that only two times in the whole history there was a 01:10.960 --> 01:20.840 Commodore 900 sold on eBay. And one of them was bought by me. So in 2014 I acquired this 01:20.840 --> 01:28.000 beautiful work station with no keyboard, no mouse, no screen, no software, entered 01:28.000 --> 01:33.440 already didn't power on as well. So since I have only 15 minutes today I cannot 01:33.440 --> 01:39.520 tell you everything I did to make the machine work but this is what I wanted to show 01:39.520 --> 01:45.120 you. When I finally was able to turn it on I saw that it was trying to load the 01:45.120 --> 01:50.760 operating system from the hard drive and showing me a very helpful and informative 01:50.760 --> 01:58.640 message saying start to sff. So what the f is start to sff. There's no mention of it in 01:58.640 --> 02:04.400 the documentation. So after scratching my head for some time I realized that the only 02:04.400 --> 02:09.080 way to find out was to disassemble the boot ROM and try to understand what 02:09.080 --> 02:21.080 this is doing. So anyone here ever programmed the Z8000. Me neither. So I had to learn 02:21.080 --> 02:28.040 and after going through approximately 300 pages of this I found the place where the 02:28.040 --> 02:33.520 computer was trying to access the disk and it works like this. It places a 02:33.520 --> 02:38.800 common to the disk controller into the memory and the disk controller is supposed to 02:38.800 --> 02:44.760 override the status byte with its response. So if the status is still ff it means 02:44.760 --> 02:52.000 the disk controller never responded at all. Why? Maybe it's broken. So I thought if I 02:52.000 --> 02:57.600 can replace the disk controller maybe I could make the machine work but the problem was 02:57.600 --> 03:04.600 when I entered the disk controller name into Google I got zero results. Nothing. 03:04.600 --> 03:08.800 Today if you entered the disk controller name into Google you will get many 03:08.800 --> 03:13.600 results but all of them are me asking for help on different forms. 03:19.600 --> 03:25.160 So turns out this controller is completely custom made just for this machine so I can't 03:25.160 --> 03:30.720 replace it. So if I can replace it maybe I can fix it. So I started examining the 03:30.720 --> 03:37.360 disk controller board and I found the broken chip. So I was so happy for about two minutes 03:37.360 --> 03:41.360 and the output the machine on and I so didn't know it was still giving me the same 03:41.360 --> 03:49.720 error. So I replaced some other chips on the board. Nope. So the same error. So we flash 03:49.720 --> 03:55.320 the micro controller on the board. Nope. Still the same error. So I thought okay maybe 03:55.320 --> 04:00.120 I will disassemble the firmware of the micro controller and they I will understand what 04:00.120 --> 04:07.120 it's doing and why it's not responding. Yeah anyone here programmed the Intel 8048? 04:07.120 --> 04:15.400 You did. You have my condolences. It's a very old and very primitive micro controller 04:15.400 --> 04:21.520 from the 70s. So after going through the disassembly for many days I still had no idea 04:21.520 --> 04:27.520 what the code was doing. But fortunately I found an ASCII string with the copyright note 04:27.520 --> 04:40.640 and the name of the developer who will the firmware. So I found the guy. Yeah so I found 04:40.640 --> 04:50.600 the guy only to in and sent him a message asking for help. And he never replied me back. 04:50.600 --> 04:55.800 So I was on my own and I thought okay maybe that this controller is not broken. Maybe 04:55.800 --> 05:02.120 the disk is broken. So I bought the identical hard drive and headed shipped from United 05:02.120 --> 05:09.280 States and nope still the same error. So I bought a completely different hard drive and headed 05:09.280 --> 05:17.440 shipped from United States and wonder of wonders. I saw a different error message. So instead 05:17.440 --> 05:24.960 of status FF the computer was now turning me bedfile type. Any probablin means that the computer 05:24.960 --> 05:30.960 does not understand the file system that's on the disk. But it also means that this controller 05:30.960 --> 05:37.440 works and the disk works and the computer can read data from the disk. So how is it possible 05:37.440 --> 05:44.080 that a completely random drive from eBay works and the original one doesn't. The replacement 05:44.080 --> 05:49.360 for the original also doesn't. Well if you go back to the second slide that I showed you it 05:49.360 --> 05:57.520 is MFM hard drive and MFM hard drives needs to be low level format it before you use them. 05:57.520 --> 06:04.880 So by pure luck I was able to buy a disk that was format it in the same way that my disk 06:04.880 --> 06:12.800 controller wanted. And the original disk was not format it. So the computer couldn't use it and instead 06:12.800 --> 06:19.440 of giving me a proper error message that this controller just went and infinite loop trying 06:19.440 --> 06:24.880 to find a sector on an unformatted disk. So maybe it's a good thing that the firmware guide did 06:24.880 --> 06:29.600 not respond to me because now I had a thing or true to say to him about a proper error error. 06:30.480 --> 06:39.200 But okay I had a disk now but unfortunately after playing with the disk some more it turned out 06:39.200 --> 06:48.320 that every 17th sector was still giving me a error FF. Why? Well 17 turns out so be exactly 06:48.320 --> 06:55.200 the number of sectors per truck. And since this is a disk that came most likely from a PC 06:55.280 --> 07:02.640 if you format a disk on a PC the sectors are numbered from one. But this is a unique machine so 07:03.360 --> 07:11.520 maybe it needs a sector to be numbered properly starting from zero. So I had to reformat the 07:11.520 --> 07:18.160 disk anyway. So I went back to the guide that sold me the hard disk and I thought hey I bought 07:18.160 --> 07:23.280 the hard disk from you can you tell me which controller you use with it so I can buy it as well 07:23.360 --> 07:28.400 and use it to reformat it with different sector number. And he was like that's a method just 07:28.400 --> 07:35.120 format it in your old machine and I said I can't format it in my own machine because I do know 07:35.120 --> 07:42.320 how. So just tell me which controller you use and then I will try to use it as well. And he was like 07:42.320 --> 07:48.400 that's a method just format it in your own machine. Just going back and forth like this a few times 07:48.400 --> 07:56.000 as I said finally okay I am going to format in my machine. So how can I do that? Well this screen tells 07:56.000 --> 08:07.920 you press any key twice. Don't do that. Instead if you press one and the nine you will go into 08:07.920 --> 08:14.960 a machine language monitor and a machine language monitor allows you to put data into the memory and 08:15.120 --> 08:21.600 like I told you this is exactly the way you communicate with the disk controller. So I could use it 08:21.600 --> 08:28.640 to send a format disk commands to the controller and the only tiny little problem is this comment 08:28.640 --> 08:40.960 is not implemented. So now I really had a few things to say to the firmware guide but I thought okay 08:40.960 --> 08:48.000 they they had to be a way to format the disk somehow right. So I went back to the firmware 08:48.000 --> 08:54.160 this assembly and I found out that okay there is no format disk commands but there is a format track 08:54.160 --> 09:02.560 comment. So I could enter comments to format individual tracks one by one and there are only 2600 tracks 09:02.560 --> 09:12.000 on the disk. So if I started in 2014 I would probably be finishing a run now. So how can I do 09:12.000 --> 09:20.720 it better? Well this is a unique server right? So how do you access a unique server? Today you 09:20.720 --> 09:29.120 would access it over a network in 1985 you access it over a terminal. So if I could attach a PC 09:29.200 --> 09:36.000 and make it act as a terminal and pretend that I'm typing all those track formatting commands 09:36.000 --> 09:40.000 I could make it work and this is the program that does exactly that. 09:50.080 --> 09:57.680 So now I had a properly formatted disk I was ready to put software on it software that I didn't have. 09:59.840 --> 10:06.880 But fortunately there are images of the installation floppy on the internet. So I could download 10:06.880 --> 10:14.320 the images and make the floppy. How do I make the floppy? Well the images are 1.2 megabytes 10:14.320 --> 10:21.200 inside. Inside the floppy is a 5 inch. So maybe I could just make them on a PC right? 10:21.760 --> 10:27.600 Now it turns out I can't because it's Commodore and Commodore uses a different disk encoding than 10:27.600 --> 10:35.360 everybody else. So maybe I could get a Commodore disk drive from the Commodore pads that also 10:35.360 --> 10:43.360 uses GCR encoding and use this one to make the floppy. One turns out I can't because it's Commodore 10:43.360 --> 10:50.320 but unique Commodore. So the sextos are bigger than on the 8 bit machines. So maybe I could hack 10:50.320 --> 10:55.760 a Commodore floppy drive to use bigger sectors. Noters like I can't because the track density 10:55.760 --> 11:06.880 is different as well. So at this point I was like really guys. So in the end what I had to do 11:06.880 --> 11:13.600 was to go back to my disk formatting program and modify it so that it puts data for every 11:13.600 --> 11:20.800 sector into the computer memory and issues the sector right comments to the floppy controller. 11:20.880 --> 11:24.480 And it took this way it took only 18 hours to make one floppy. 11:29.360 --> 11:36.640 Provided that there was no arrow in the middle. So after a week or so I had this beautiful set 11:36.640 --> 11:44.000 of installation floppy. I could use to put the system on my properly formatted hard drive. 11:44.000 --> 11:47.200 And when I did that this is what I got. 11:59.040 --> 12:03.760 And if you look at this photo carefully you will see that the root account has no password. 12:05.600 --> 12:12.560 So apparently that's how you use the Unix in 1985. Thank you very much for your attention. 12:14.960 --> 12:16.960 Thank you. 12:16.960 --> 12:37.960 I have been in touch with the guy from the Richard Lane Cave channel, because I'm going 12:37.960 --> 12:40.960 on 100 times 10 as well. 12:40.960 --> 12:50.960 I haven't been in touch with the guy from the YouTube channel, what's the name of the channel? 12:50.960 --> 12:55.960 Richard Lane Cave, I have seen the video, but I have not been in touch with him. 12:55.960 --> 13:01.960 He made the video recently, and I did this like 11 years ago. 13:01.960 --> 13:11.960 So no, no, I haven't. 13:11.960 --> 13:22.960 How did I celebrate? I'd rather not say. 13:22.960 --> 13:25.960 Sorry? 13:26.960 --> 13:31.960 Possibly? 13:31.960 --> 13:35.960 Great folks for how are you doing? 13:35.960 --> 13:46.960 When you finally got the floppy image, we installed the system through your already pop at the top right. 13:47.960 --> 13:57.960 Unfortunately, no, it turns out that the system installation disks already assumed that your hard drive is formatted. 13:57.960 --> 14:14.960 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. 14:17.960 --> 14:21.960 I have been in touch with the guy from the Richard Lane Cave channel. 14:21.960 --> 14:26.960 I have been in touch with the guy from the Richard Lane Cave channel. 14:26.960 --> 14:31.960 I have been in touch with the guy from the Richard Lane Cave channel. 14:31.960 --> 14:37.960 I have been in touch with the guy from the Richard Lane Cave channel. 14:37.960 --> 14:42.960 I have been in touch with the guy from the Richard Lane Cave channel.