On this channel, we dive into old school technology, focusing heavily on vacuum tubes. My primary goal is to build computing circuits based off the legendary machines of yesteryear, only with a slight modern twist. All the tubes will be operating with very low voltages on the plate, making the projects safe and easy to follow along with. So, lets grab our multimeters, some random tubes and a low voltage power supply and have fun!
Usagi Electric covers one of my main passions, while my other main passion can be found over on Usagi Motors.
Another episode on the mini Centurion, Yah! Nice well things are still fresh. But definitely time to go off on another topic for a while. Especially after assembly if you're not used to assembly. There are 10 binary reasons to program in assembly.
Assembly programming is NOT hard (I spent 46 years doing it). What you're probably facing is device interfscing, and that can be a bit fiddly(I need to admit that I'm less than 2 minutes in... (Although it's not that difficult on IBM mainframes.)
This reminds me of my CPSC degree back in the 90s. Late night in the lab. Working hard to get something to happen in a low level language. 2AM it finally starts working and there is a mini celebration.
Great bare metal assembly coding! This reminds me of experimenting with the track format command [WD1797] in 1985, squashing the preamble and inter-sector gaps enough to fit an 11th 512 byte sector in (and over-stroking to 83 tracks) to reliably increase my Nascom 2 CP/M floppy free space from 786K to 898K.
I did a lot of Z80 on my Nascom 2. If the program is small, I don't even need an assembler (or disassembler); I know Z80 in hex! When programming on my PC, I find the C x86/x64 intrinsics make most things possible (SIMD, AVX), but I still need the extra control that assembly coding provides to do optimizations that the C compiler can't manage. Sometimes, assembly coding is the only way to ge the job done!
It's not just doing asm, it's doing asm in hard mode (without a debugger such as gdb, and does the Centurion CPU even have any debug support? You can still make a debugger without it, but that's quite hard too!)
Not stupid, it is just what happens when you are not a software person. A software person like myself probably couldn't have even gotten the system working to the point of being able to run that program. hardware is a magic box that does what I tell it but if it doesn't do what I tell it 🤷♀ time to do something else and try again tomorrow
The more difficult and complex the program, the more time you need to take to step back and clear your head. The most effective problem solving technique: a good night's sleep.
David, the next time you're able to talk with David Gesswein, please ask him how *he* pronounces his last name. I think you mispronounced it, but I'm just as likely to have been mispronouncing it for years too. ;) Also, will you be posting these podcasts on this channel (for those of us who miss it live)?
David, I love seeing the comments in this piece of code! In the Increment routine: "Shabloinks A, B, and Z registers" LOL! I don't speak Japanese as you do, but I am assuming that "shabloink" is something like "destroy"? Please advise, and good luck in Dubai and at VCFSW! BTW the "Round 1"... "Round 6" thing is real life in embedded programming! But you persevered to the end, and it worked! Congrats!
I was rejoicing and cried tears of joy with you on seeing all your hard work and effort scroll up that screen with a successful result! Keep up the good work!
Well the way we did that kind of thing was write 'C' programs to write 'Assembly' programs ;) don't ask me to do that again I haven't done it since before you where in 'short pants' and I do not have all the 'C' code that would emulate the platform we where programming to. ;)
Am I missing something? The reason why he can't low-level format the disk is because the format command isn't accessible to the Mini Centurion. So either the format command that he has on his other drives is for the v6 CPU only, and hence is incompatible with the Mini Centurion, or he can just copy the format command file over to a floppy disk, move the floppy drive and controller card to the Mini Centurion and copy it over to the removable platter (or run it directly from the floppy, if possible). Assuming the former situation, where no v5 CPU format command exists, it would seem feasible to connect the Hawk drive in question to the v6 CPU (without moving the drives from the cabinets, just string a cable) and low-level format the drive using the v6 CPU & operating system? Or is the low-level format different between v5 & v6 CPUs?
The Centurion dealer in C. Ohio removed the CPU5 JCL [ .Format ] command from the CPU5 OPSYS on the disk that they gave to the dealers customers. Some dealers removed the [ .Format ] command from the OPSYS so the customer had to purchase all the disk packs they needed from the dealer at a higher than normal street price. - When the CPU6 OPSYS was written the disk file-system was updated with new features that made the JCL (Job Control Lang. ) [ .Format ] command only "format" the disk platter in a way that the platter only worked on CPU6 systems, not CPU5 systems.
Oh lordy lordy, I remember that feeling. Late at night, hours and hours of effort and failure, and then... success! Up until the success all you want to do is go to sleep, then when it works you are so happy you want to waste more time playing around and experiencing the joy. I sort of miss those days but... nah... nope, I don't miss it.
If you ever come accross a HARRIS/5 grab it. It's a early 70's computer with 48k core 24bit words memory. And removable cart drives 5meg if not mistaken that look a lot like the ones ued in the centurion. I don't have any hardware but i do have an image of the OS on a PC media.
I'm so happy for you! When I look back at what the Centurion was like 3 years ago when you first got it, I'm flabbergasted! Sadly my bunny died 1 hour before you're video was released...
I have watched each and every episode about the Centurion and have loved every minute of it all !!! Now this is just an idea here, but what if you were to write a book about the Centurion ? Maybe explain how to make a homebrew replica of it ? Like I said, it's just an idea.
_As a software developer of over 40years experience. Started assembly/machine code on a commodore PET. It's not about being smart, or dumb. Its all about being methodical and unrelenting. _*_Well done._*
Congratulations from N. Ireland. Been following your Centurion blues (accidental pun!) for a while, I'm of an age to remember other old stuff like Datapoint 2200.
