I no longer have to drag my butt anywhere everyday, but I do enjoy revisiting a time where I understood how shit worked. I can appreciate the 'eureka!' moment of throwing a switch and getting a prompt (without the need for a fire extinguisher).
G'day from Australia It's Monday here, but I'm working a night shift, so also watching before work, three hours before I need to be out of the house and on the road to work.
I hope this doesnt get lost in the comments but just a little reminder: it seems that you have connected the mains live wire to the center pin of your toggle-switch. This means that the second terminal of your switch is live all the time the device is turned off. And since that contact is openly accessible It may be sensible to either change the two connections (then mains is on the outside and not connected while in the off-position) or at least to secure it against you touching it. After all i want to keep getting centurion updates and not hospital ones ;)
A 555 ... THANKYOU!!! Seems everyone throws an Arduino or a Pi Pico at simple stuff like this these days. Grid frequency will drift about too, although it's nominal frequency would be 60Hz, so I wouldn't worry about a tenth of a second or two. Oh and happy year of the rabbit! 🐰
Just a suggestion, but for the wooden panels you can buy rolls of self-adhesive vinyl wrap with a woodgrain effect. They're normally used as a quick fix for old furniture where the veneer has started to break away but might help to make your mini Centurion look a little more like the full sized one.
Centurion actually used glue on rosewood veneer on MDF themselves for the genuine panels, so that's a really excellent idea! I have some ideas I'm mulling around for how to vastly improve this design in time VCF East in April, so quite a lot will get remade and I think like you suggest, I'll go with something a little closer to how Centurion actually built it back in the day.
@@UsagiElectric Another idea is to visit IKEA and buy Sinarp kitchen cover panels, veneered in walnut, and cut to appropriate size. That would probably look very similar to the Centurion panels.
@@UsagiElectric That's interesting! Really surprised to hear they actually used MDF panels. I assumed they'd just silk screen printed a wood effect directly onto the metal. You learn something new every day!
thats awesome, but one thing i would do for safety.... you need to ground that main power switch... if anything happens in that switch, that whole thing and the bracket can become live. Also, i would put some big heat shrink over those brackets that you made for the ribbon cables
See you next SAT. Hope you take a few videos at the event on the 28th to show off the first Centurion model in 30+ years. Intro of the Mini-Centurion single 8" floppy system. Also noticed you now have two working Centurion ADDS terminals.
Great job! A couple of suggestions though: (1) Run a green ground wire from the power cord to all the metal parts, including the power switch. You never know when a short might develop or a critter might try cuddling up or into a power supply. Don't rely on the flat cables to pass short-circuit currents. Don't ask me how I learned that is a hugely poor idea. (2) Add a circuit breaker or fuse of appropriate size right at the power inlet, in the black hot lead.
It just blows my mind how much troubleshooting is involved with making this an actual working system! I'm pretty well convinced that we have it way too easy with relatively stable modern systems, and programming languages that don't rely on a minuscule amount of memory to get the job done. I think the Centurion is going to be a big hit at the show if it continues to work as advertised!😄👍
What an incredibly entertaining journey that made me feel way smarter than I actually am. Shared passions will do that, but moreso it is your keen ability to share the project in such an easy-going manner. Also, the case is stunning!
You could extract the 60Hz signal from mains with a simple PCB-mounted transformer. If all fails, just gut an old wall wart. They usually consist of a transformer, full-bridge rectifier and optionally a linear regulator. The 555 will seriously have trouble keeping time.
@@kdrum90 I doubt it's at a fraction of the cost, but yes, you could. A transformer will be self-sufficient in this case, though, because it's its own power supply.
Nice to see that you managed the system to work. I am 69 and grew up with this type of machines. Are you interrested in a working Atari portfolio? The first portable MSDOS computer that fits in your pocket. It is a complete set with parrallel and serial extension port and also a removable 128k Memory card. its working on 4 AA batteries, Only the optional powersuply is missing but can be replaced by a small 6Volt PSU.
I once saw somebody disassemble a computer like this. And they removed the module that controls the text in-out interface, and they were hotwiring the blinking cursor module just by connecting a powered cable on a metallic terminal on the circuit, and manipulating the blinking. They made the cursor blink, then they made it stop blinking, and they made the cursor just stay. It was really cool.
This is so cool. I'd be first in line to see it if I could get to Texas. One idea - rounding off the edges of the ribbon cable hold-downs would protect the cables if they were to rub up against the sharp edges. The machine will be moving around, after all.
I once built a work bench PC from junk I had lying around, using two 5.25 floppies, 360k. 286 main board. First disk was the OS, second disk had a QBasic program to generate test screens for adjusting CRT monitors, test printers, etc. I remember it was a lot of fun to build and get working.
That's really cool! I think it turned out great considering the time constraints. Although I am a little disappointed you didn't make the power switch a key lock that you don't have the key for, so you had to pick it to start the computer.
Great work! I know the process of recording the build must have been a lot of work on top of the tight deadlines, but also it is super cool to watch the project come together. Thank you very much!
Thank you! This video had quite a lot of different shots taken throughout the build. A normal episode uses around 50 different shots, but this one clocked in at near 150 shots! But, it was fun showing the whole build process start to finish, even with the little things like making brackets.
This was an absolutely beautiful and stunning build! I don't think Centurions ever made it to Denmark, but they are before my time, so I really don't know. I did learn assembler programming on a DEC Professional 350 (LSI-11?) though, back in 1988. So I'm watching your new PDP-11 videos with great interest. Greetings and a big "Hurrah, well done!" from DK!
Huge success! What a brilliant project. I'm sad I can't be at the meetup to see it in person. Looking forward to your recap of the event, and next week's PDP content!
Thank you! I'll try to take some pictures, but usually at these events, I'm so busy talking with people that I don't get a chance to get the camera out unfortunately. But, we're not done with the mini-Centurion project though because VCF East is coming up, and the mini-Centurion needs to evolve a bit for it!
As of the last video, I realized you are DFW-ish. Will be heading to the Meetup and look forward to seeing the mini. Really have enjoyed your videos. Cheers
One thing of note with power supply timing is take a look at the 4116 memory datasheet, you'll see that Vbb (-5v) should be applied first and removed last, so there is at least that power sequencing requirement (in reality the computer manufacturers I'm familiar with that used that memory didn't bother and let it all turn on and off at the same time, and the chips still work fine decades later!) so it's worth having a look to see if there are any power supply sequencing requirements when you have multiple supplies.
This is so cool. But I would really love to see a video going full deep dive on the issues surrounding this OS. Its so wild finding out that it's still being used in some capacity, absolutely crazy.
This is actually a part of the whole story of Centurion that I'm working on figuring out. I've been building a timeline of the company from inception to today by talking to various people who used to work there, and I'm starting to get a good picture. Unfortunately, the current IP holder has been... less than helpful, but I'm nothing if not persistent, so I'll get the full story eventually!
Ack! I forgot to like this first time through, so I'm watching it again. This mini-Centurion is a beast. I wonder if it would be possible to interface an old MFM drive to it to provide it with a hard drive. The Centurion and this new mini have been quite the project. (You might cover the edges of the ribbon cable clamps with some 3M Super 88 or some extra large olefin-based heat shrink tubing, just to give the ribbons some protection.)
I believe the Finch is an early MFM or an ST506-style drive with a modified pinout. The floppy drive is a regular Shugart-type from CDC which only has an adapter to connect it to the FFC card, so that would mean the Finch also has a Shugart/ST-506 style interface with only a different pin setting. Similar adapter boards could be made to take a regular 5,25" floppy and an original ST-506... both of which he has sitting in his PDP-11 chassis in the background.
@@Stoney3K There may have been several models of Finch (there doesn't seem to be much documentation). I don't think the Finch that interfaces with with the FFC card in the Centurion is ST-506/MFM (if I am wrong, life will be a lot easier). The later smaller Wren drive had at least four different interfaces: Finch like, ST-506, ESDI, SCSI
Interesting memory board. the "stagger" on it is a brilliant idea. For someone who thinks in dead verticals and horizontals it seems wrong, but it gives better line traces out and in, which takes some thinking
How about using some peel and stick vinyl with that wood grain pattern and color on your wood pieces? It's what many travel trailer companies do over MDF and OSB.
Hey, Btw, if you want to match the other systems wood paneling the color stain they used (or simulated) was black walnut. You can put it right over the top (assuming you didn't varnish the panels yet) of the existing panels and it will take the color back to more of a brown.
This build really deserves a de-luxe cabinet with real walnut and smooooth spray painted aluminium panels. And this not a critique of the one built - given the lack of woodworking expertise and the hastened construction, it is very impressive. And very true to the design of the originals, obviously! Just amazing!
Occasionally on snapped pins a small rare-earth magnet will pull them out when you can't find a small enough pair of tweezers, or want to save replacing the socket as a measure of last resort...
Have a great time at the event! One idea - make the back panel latched so it can be lowered and people can see the back. Not sure how interesting that may be…
Question. Could not you eventually get a backplane made to put the CPU6, MUX, and RAM cards (and maybe a floppy controller), and put the drive next to the four cards? you could cut the X dimension in half, you could also possibly change the orientation of the cards to make the centurion's actual computing hardware no bigger than the FDD's outer shell. For extra portaility you could even get a non period accurate MFM SSD, which is against the goal of this project, but you'd save on weight and reduce the physical dimensions even further. This is all in the eye of the beholder, but power supplies and storage are definitely not as important as the actual hardware, authenticity wise, than on which the software runs on (). It would make carrying it to conventions so much easily. This all is for a potential Mini-Centurion Mark II, since all you had was a week to get things done
Nice work on getting the mini Centurion built and running. The one thing still is some text beside the buttons and lights on the front panel. If it was me working I would wire up a small circuit to get 60Hz from the mains supply. The 555 timer may be good enough for demonstration purposes as you going to be running the machine for days on end without turning it off. 60.2 Hz means it will be about 28 seconds fast each day (if my math is right). It isn't very accurate. You could change the ratio of the fixed timing resistors vs the variable one so you can get better accuracy in the 60Hz signal. Another option is use a faster signal and divide it down. Have fun at the show.
@@davidellsworth4203 That's a very good question. I have no idea. I ran the numbers again and it is indeed a drift of 4.8 seconds per day. Me being me, I would still aim for better than that. :)
@@kevincozens6837 4.8 seconds would be pretty acceptable for this level of project. But *4.8 minutes*, which it was actually off by, is quite bad indeed :-) And yes the Centurion OS is not Y2K compliant, so he can't set the actual current date on it. But from the looks of it when he was adjusting the 555 timer, it would not have been hard to get it to be much more accurate - and I think it would've been worth it.
Re: libraries and tracks/sectors, this sounds a lot like VSAM or mainframe data sets. I've been following your Centurion videos closely, and I wouldn't be surprised the authors from the Centurion OS were MVS users in the past - a lot of parallels between the Centurion OS and MVS exists.
Its really interesting to see how stuff like folders and such were set up in the era tbh like it makes sense if u think about it but id have never guess it, also really wild how small the files end up being like you have the whole os with the compiler and all on the floppy and still have PLENTY of space left like ?? i wasnt expecting that wow
Yeah, the OS requires a definite shift in thinking about things. It took us a lot of digging and trial and error to figure out how to min-max the OS as much as possible. Ren absolutely killed it with his script, though we've stuffed a few extra things in there since then that have pushed us up to 70 tracks, but there's still a solid 25 tracks left for building new programs, which is pretty good.
While the relays off the 5V were good, it might have been an idea to use an AND gate and opto-isolators, then you can use it as a voltage protection circuit. If one of the PSUs doesn't come up for some reason, the machine won't start one leg down.
Regardless of the small negatives, that's still the world's first portable centurion, no? oh and with bloatware removed :D Result mate, awesome job and wonderful build and view to see too :D
Regarding the display "Fail" message, the status indicates DMA failure. Since the self-test is for the memory and IO, I have to assume it's DMA with the UART. It doesn't give any more details. I got this out of a ADDS Regent 200 manual. I'm hoping that's close enough to what you have.
Cat went down the drain! 🙂. The mini Centurion is actually pretty cute. How about a mini retro Centurion in time for Christmas! Like retro game consoles.
With triple-supply DRAM (4116's) in there, you would probably be better off making the -12V come on first. The 4116's don't like not having the -ve bias up when the +ve voltages are applied.
yep, if the -5v line isnt present when the other 2 come up, they can pass heavy current and be damaged , this happens a lot in zx spectrums with dc-dc converter issues
Love this little brother !!!!!. Any chance of emulating the hawk for this machine using a HW of some sort. You have very smart guys behind this project
I bet you could get a 60 Hz signal from the mains by using an optocoupler like PC817. As a bonus, the corresponding circuit would actually be much simpler than 555 oscillator.
And more accurate. The 555 isn't temperature compensated or anything, so even if it was dialed in precisely to 60 Hz initially (and it wasn't, so...), any change in the local environment can cause it to drift a little one way or the other. I mean, I get how simple the 555 approach is and I can't argue with that. But it's about the least accurate way to provide the necessary clock signal. There are many other options that would be better, from an accuracy standpoint (even if not expediency).
Core memory. Sounds tempting. Sounds *very* tempting actually, he-he. I wonder if....... Nah.... Or...... Well.... I bet one day...... Yeah. With core memory. Delightful episode. There's just something with these more or less 300 Baud speed text based systems. It's like you can feel the data coming through the wires. Immensely satisfying.
One small thing to check, because you're (hopefully) going to be using this for years you might want to think about putting inrush current limiters in your +-12v lines. When the relays close any capacitors on those lines are going to get hit pretty hard as they try to charge limited only by their internal resistance. I'd hate for you to power on at an event then blow up an old cap. You can get little disk type inrush limiters but I'm not sure what the load is on your supply if they will be up to it. Similar idea to your soft start circuit on the tube processor but running in a fraction of a second instead of a fraction of a minute ;-)
Rather than the 555, you could get your 60Hz signal from a very small AC transformer connected to the mains, but with a low voltage output. Then it would be guaranteed to have the correct number of cycles per day form the power company.
Just for the fan pun I hit the thumbs up! Nice work brother, looks good from here. I think your videos are great and your a wealth of knowledge so keep up the awesome work and have a great day.
I'm glad someone caught the fan pun, I laughed to myself quite a bit when I said it while recording the voice-over! Thanks for the kind words on the videos, it's awesome to hear you're enjoying them!
@@UsagiElectric I have a Compaq 286 Luggable with Monochrome plasma screen and detachable keyboard. The idea of finding something like that with (non standard display parameters!) a surround bezel in Centurian colours and a wander keyboard of any kind really would be fun. Our DEC computers at college had Newbury terminals because they were cheaper than DEC
That's fantastic. It looks great and it works. Best of both worlds. My projects are either one or the other, seldom both. (sometimes neither LOL). Good luck at the show. :)
Speaking of library’s this kind reminds me of MVS datasets. However with datasets you have extended space available so when it fills up it will consume a new track each time it overflows.
You could have used a 4-pole relay and just used 2 power switches to turn the unit on, one for the AC and one for the DC once the power-supplies stabilized.
The Centurion Veles (because it's light [ish], portable[ish], and veles goes with centurion) build came out well. I wonder how difficult it would be to modify the stripped down OS to use the memory card a bit more and speed up operating time.
I tried making something like this. I had some scrap styrofoam pieces, in symmetrical shapes. I made it look like some sort of crt. An Ipad or screen could fit in the one styrofoam piece, what had a square opening. The back of the styrofoam tv, has to parts that open up.
I would go another way. Take tools, yeah, .. .but because there will be folks wanting to look inside some cool stuff, with "open brain Centurion" , . . if it is possible ., . I know I would! God speed ..
I realize this is all after the fact now, but if memory serves me correctly, the @JX files are the JCL command files, @TX are the transient files, the OSEG files are I believe chunks of the operating system executable code, the IOD files are likely the IO driver executables. Like I said, "if memory serves me..." it has been over 40 years since I worked on those systems.
Why not a single +5 +12 -12 combo PSU, hell why not just an ATX PSU? This seems way overboard on complexity, although bonus points for using MeanWell, very good PSUs.
Anybody else using these videos to respark the joy of the job before dragging butt into work Monday morning to turn stuff off and on again? IT is fun!
I no longer have to drag my butt anywhere everyday, but I do enjoy revisiting a time where I understood how shit worked.
I can appreciate the 'eureka!' moment of throwing a switch and getting a prompt (without the need for a fire extinguisher).
Come to the dark side, security, you can watch credential stuffing attacks all weekend.
Same here haha
G'day from Australia
It's Monday here, but I'm working a night shift, so also watching before work, three hours before I need to be out of the house and on the road to work.
These videos ARE my Monday morning.
I hope this doesnt get lost in the comments but just a little reminder: it seems that you have connected the mains live wire to the center pin of your toggle-switch. This means that the second terminal of your switch is live all the time the device is turned off. And since that contact is openly accessible It may be sensible to either change the two connections (then mains is on the outside and not connected while in the off-position) or at least to secure it against you touching it. After all i want to keep getting centurion updates and not hospital ones ;)
That's actually something I totally didn't think about!
I'll swap the two connections next time I head out to make it safer, thank you so much!
A 555 ... THANKYOU!!!
Seems everyone throws an Arduino or a Pi Pico at simple stuff like this these days.
Grid frequency will drift about too, although it's nominal frequency would be 60Hz, so I wouldn't worry about a tenth of a second or two.
Oh and happy year of the rabbit! 🐰
The first program you run at the meetup HAS to be hellorld!!!
Just a suggestion, but for the wooden panels you can buy rolls of self-adhesive vinyl wrap with a woodgrain effect. They're normally used as a quick fix for old furniture where the veneer has started to break away but might help to make your mini Centurion look a little more like the full sized one.
Centurion actually used glue on rosewood veneer on MDF themselves for the genuine panels, so that's a really excellent idea!
I have some ideas I'm mulling around for how to vastly improve this design in time VCF East in April, so quite a lot will get remade and I think like you suggest, I'll go with something a little closer to how Centurion actually built it back in the day.
@@UsagiElectric Another idea is to visit IKEA and buy Sinarp kitchen cover panels, veneered in walnut, and cut to appropriate size. That would probably look very similar to the Centurion panels.
Gold will short fall
Brilliant! 🏆
@@UsagiElectric That's interesting! Really surprised to hear they actually used MDF panels. I assumed they'd just silk screen printed a wood effect directly onto the metal. You learn something new every day!
Your ingenuity and patience are both astounding . Thank you.
Thank you so much! I'm happy with how it came together!
thats awesome, but one thing i would do for safety.... you need to ground that main power switch... if anything happens in that switch, that whole thing and the bracket can become live. Also, i would put some big heat shrink over those brackets that you made for the ribbon cables
I love the Centorini
See you next SAT. Hope you take a few videos at the event on the 28th to show off the first Centurion model in 30+ years. Intro of the Mini-Centurion single 8" floppy system. Also noticed you now have two working Centurion ADDS terminals.
I agree. Your clock is going to drift. I'd suggest getting a board with 32767 HZ crystal oscillator and circuit to produce your 60 Hz signal.
Catch you next weekend Ken, it'll be fun to get you hands on with the mini!
Great job! A couple of suggestions though:
(1) Run a green ground wire from the power cord to all the metal parts, including the power switch. You never know when a short might develop or a critter might try cuddling up or into a power supply. Don't rely on the flat cables to pass short-circuit currents. Don't ask me how I learned that is a hugely poor idea.
(2) Add a circuit breaker or fuse of appropriate size right at the power inlet, in the black hot lead.
Really enjoying this series of videos.
Sadly I’m not even on the same continent but I hope the meet-up is a roaring success!
It just blows my mind how much troubleshooting is involved with making this an actual working system! I'm pretty well convinced that we have it way too easy with relatively stable modern systems, and programming languages that don't rely on a minuscule amount of memory to get the job done. I think the Centurion is going to be a big hit at the show if it continues to work as advertised!😄👍
What an incredibly entertaining journey that made me feel way smarter than I actually am. Shared passions will do that, but moreso it is your keen ability to share the project in such an easy-going manner.
Also, the case is stunning!
Thank you so much!
I'm pretty happy with how it turned out, but I'm already thinking about how we can improve it for VCF East in April!
I love all of the work you've put into this, Great work!
Thank you so much!
Ahhh! A new video right at my bed time before the college exam tomorrow!! Guess I HAVE to watch it ^^
The cats would be happy if Usagi Electric would use some of the scrap plywood to build nice cozy cots for them. 🙂
You could extract the 60Hz signal from mains with a simple PCB-mounted transformer. If all fails, just gut an old wall wart. They usually consist of a transformer, full-bridge rectifier and optionally a linear regulator. The 555 will seriously have trouble keeping time.
Optocoupler would do the same at a fraction of the cost.
@@kdrum90 I doubt it's at a fraction of the cost, but yes, you could. A transformer will be self-sufficient in this case, though, because it's its own power supply.
Can't wait to see it at the meetup, it looks adorable
Excellent, will catch you there!
Nice to see that you managed the system to work. I am 69 and grew up with this type of machines.
Are you interrested in a working Atari portfolio? The first portable MSDOS computer that fits in your pocket. It is a complete set with parrallel and serial extension port and also a removable 128k Memory card. its working on 4 AA batteries, Only the optional powersuply is missing but can be replaced by a small 6Volt PSU.
I once saw somebody disassemble a computer like this. And they removed the module that controls the text in-out interface, and they were hotwiring the blinking cursor module just by connecting a powered cable on a metallic terminal on the circuit, and manipulating the blinking. They made the cursor blink, then they made it stop blinking, and they made the cursor just stay. It was really cool.
This is so cool. I'd be first in line to see it if I could get to Texas. One idea - rounding off the edges of the ribbon cable hold-downs would protect the cables if they were to rub up against the sharp edges. The machine will be moving around, after all.
"MINOS" eh? Are you building a retro computing labyrinth? Well done on the custom mini Centurion
maybe MINOcenTAURion
I thought that name was reserved for discrete PNP transistor builds...
I once built a work bench PC from junk I had lying around, using two 5.25 floppies, 360k. 286 main board. First disk was the OS, second disk had a QBasic program to generate test screens for adjusting CRT monitors, test printers, etc. I remember it was a lot of fun to build and get working.
Hope you Have Fun at the Event...And Load up the Simple Program HANG-MAN....
That's really cool! I think it turned out great considering the time constraints. Although I am a little disappointed you didn't make the power switch a key lock that you don't have the key for, so you had to pick it to start the computer.
I thought about it! But, I figured for version 1 here we'd go simple with a switch.
Version 2 though, that's going to be a lot more interesting!
I'm absolutely awed, no, overawed by how much you got done in a week.
Thank you!
After the event at the end of the month, we have two months until VCF, and I think we can build something even better by then!
Great work! I know the process of recording the build must have been a lot of work on top of the tight deadlines, but also it is super cool to watch the project come together. Thank you very much!
Thank you!
This video had quite a lot of different shots taken throughout the build. A normal episode uses around 50 different shots, but this one clocked in at near 150 shots! But, it was fun showing the whole build process start to finish, even with the little things like making brackets.
This was an absolutely beautiful and stunning build! I don't think Centurions ever made it to Denmark, but they are before my time, so I really don't know. I did learn assembler programming on a DEC Professional 350 (LSI-11?) though, back in 1988. So I'm watching your new PDP-11 videos with great interest. Greetings and a big "Hurrah, well done!" from DK!
Huge success! What a brilliant project. I'm sad I can't be at the meetup to see it in person. Looking forward to your recap of the event, and next week's PDP content!
Thank you!
I'll try to take some pictures, but usually at these events, I'm so busy talking with people that I don't get a chance to get the camera out unfortunately.
But, we're not done with the mini-Centurion project though because VCF East is coming up, and the mini-Centurion needs to evolve a bit for it!
This video, like all your others was an absolute joy. Super excited for the PDP-11!
As of the last video, I realized you are DFW-ish. Will be heading to the Meetup and look forward to seeing the mini. Really have enjoyed your videos. Cheers
Awesome, catch you there!
I'd go to the event but its a killer bus journey from Bristol UK.
One thing of note with power supply timing is take a look at the 4116 memory datasheet, you'll see that Vbb (-5v) should be applied first and removed last, so there is at least that power sequencing requirement (in reality the computer manufacturers I'm familiar with that used that memory didn't bother and let it all turn on and off at the same time, and the chips still work fine decades later!) so it's worth having a look to see if there are any power supply sequencing requirements when you have multiple supplies.
Amazing work, good luck at the event!
This is so cool. But I would really love to see a video going full deep dive on the issues surrounding this OS. Its so wild finding out that it's still being used in some capacity, absolutely crazy.
This is actually a part of the whole story of Centurion that I'm working on figuring out. I've been building a timeline of the company from inception to today by talking to various people who used to work there, and I'm starting to get a good picture. Unfortunately, the current IP holder has been... less than helpful, but I'm nothing if not persistent, so I'll get the full story eventually!
Ack! I forgot to like this first time through, so I'm watching it again. This mini-Centurion is a beast. I wonder if it would be possible to interface an old MFM drive to it to provide it with a hard drive. The Centurion and this new mini have been quite the project. (You might cover the edges of the ribbon cable clamps with some 3M Super 88 or some extra large olefin-based heat shrink tubing, just to give the ribbons some protection.)
I believe the Finch is an early MFM or an ST506-style drive with a modified pinout. The floppy drive is a regular Shugart-type from CDC which only has an adapter to connect it to the FFC card, so that would mean the Finch also has a Shugart/ST-506 style interface with only a different pin setting.
Similar adapter boards could be made to take a regular 5,25" floppy and an original ST-506... both of which he has sitting in his PDP-11 chassis in the background.
@@Stoney3K There may have been several models of Finch (there doesn't seem to be much documentation). I don't think the Finch that interfaces with with the FFC card in the Centurion is ST-506/MFM (if I am wrong, life will be a lot easier). The later smaller Wren drive had at least four different interfaces: Finch like, ST-506, ESDI, SCSI
Interesting memory board. the "stagger" on it is a brilliant idea. For someone who thinks in dead verticals and horizontals it seems wrong, but it gives better line traces out and in, which takes some thinking
Am I just imagining it, or did you suddenly learn to use adverbs? I love it.
I’m looking forward to this coming weekend. You’ve done a fantastic job in such a short amount of time.
Thank you and catch you there!
How about using some peel and stick vinyl with that wood grain pattern and color on your wood pieces? It's what many travel trailer companies do over MDF and OSB.
Hey, Btw, if you want to match the other systems wood paneling the color stain they used (or simulated) was black walnut. You can put it right over the top (assuming you didn't varnish the panels yet) of the existing panels and it will take the color back to more of a brown.
This build really deserves a de-luxe cabinet with real walnut and smooooth spray painted aluminium panels. And this not a critique of the one built - given the lack of woodworking expertise and the hastened construction, it is very impressive. And very true to the design of the originals, obviously! Just amazing!
Occasionally on snapped pins a small rare-earth magnet will pull them out when you can't find a small enough pair of tweezers, or want to save replacing the socket as a measure of last resort...
You didn't open a Centurion-related video with "HELLORLD"!!! 😭
Have a great time at the event! One idea - make the back panel latched so it can be lowered and people can see the back. Not sure how interesting that may be…
Question. Could not you eventually get a backplane made to put the CPU6, MUX, and RAM cards (and maybe a floppy controller), and put the drive next to the four cards? you could cut the X dimension in half, you could also possibly change the orientation of the cards to make the centurion's actual computing hardware no bigger than the FDD's outer shell. For extra portaility you could even get a non period accurate MFM SSD, which is against the goal of this project, but you'd save on weight and reduce the physical dimensions even further.
This is all in the eye of the beholder, but power supplies and storage are definitely not as important as the actual hardware, authenticity wise, than on which the software runs on (). It would make carrying it to conventions so much easily.
This all is for a potential Mini-Centurion Mark II, since all you had was a week to get things done
Nice work on getting the mini Centurion built and running. The one thing still is some text beside the buttons and lights on the front panel. If it was me working I would wire up a small circuit to get 60Hz from the mains supply. The 555 timer may be good enough for demonstration purposes as you going to be running the machine for days on end without turning it off. 60.2 Hz means it will be about 28 seconds fast each day (if my math is right). It isn't very accurate. You could change the ratio of the fixed timing resistors vs the variable one so you can get better accuracy in the 60Hz signal. Another option is use a faster signal and divide it down. Have fun at the show.
60.2 Hz means it will be 4.8 minutes fast each day: (60.2/60-1)*60*24 = 4.8. How did you get 28 seconds?
@@davidellsworth4203 That's a very good question. I have no idea. I ran the numbers again and it is indeed a drift of 4.8 seconds per day. Me being me, I would still aim for better than that. :)
@@kevincozens6837 4.8 seconds would be pretty acceptable for this level of project. But *4.8 minutes*, which it was actually off by, is quite bad indeed :-)
And yes the Centurion OS is not Y2K compliant, so he can't set the actual current date on it. But from the looks of it when he was adjusting the 555 timer, it would not have been hard to get it to be much more accurate - and I think it would've been worth it.
Re: libraries and tracks/sectors, this sounds a lot like VSAM or mainframe data sets. I've been following your Centurion videos closely, and I wouldn't be surprised the authors from the Centurion OS were MVS users in the past - a lot of parallels between the Centurion OS and MVS exists.
Copacetic indeed! And event sounds like it's gonna be a blast!
Perseverance pays.
Awesome work😊
Nice work dude! Love your vids!!
Thank you so much!
Its really interesting to see how stuff like folders and such were set up in the era tbh like it makes sense if u think about it but id have never guess it, also really wild how small the files end up being like you have the whole os with the compiler and all on the floppy and still have PLENTY of space left like ?? i wasnt expecting that wow
Yeah, the OS requires a definite shift in thinking about things. It took us a lot of digging and trial and error to figure out how to min-max the OS as much as possible. Ren absolutely killed it with his script, though we've stuffed a few extra things in there since then that have pushed us up to 70 tracks, but there's still a solid 25 tracks left for building new programs, which is pretty good.
While the relays off the 5V were good, it might have been an idea to use an AND gate and opto-isolators, then you can use it as a voltage protection circuit. If one of the PSUs doesn't come up for some reason, the machine won't start one leg down.
My two cents:: Cover the cable management brackets with a heat shrink tube to prevent the edge chaffing & shorting the ribbon cable.
Regardless of the small negatives, that's still the world's first portable centurion, no? oh and with bloatware removed :D
Result mate, awesome job and wonderful build and view to see too :D
If you fit a handle it becomes a luggable.
Regarding the display "Fail" message, the status indicates DMA failure. Since the self-test is for the memory and IO, I have to assume it's DMA with the UART. It doesn't give any more details. I got this out of a ADDS Regent 200 manual. I'm hoping that's close enough to what you have.
Once again, YOU MADE IT ! Congrats, man
Cat went down the drain! 🙂. The mini Centurion is actually pretty cute. How about a mini retro Centurion in time for Christmas! Like retro game consoles.
I am sure someone is 3D printing the basis of chassis for them now !
If nothing else, you now have a working backup system.
A floppy emulator hidden in the back could be real handy
New to your channel and blown away by your skills and interesting subject matter! Looking forward to more PDP-11 developments!
Diggin' the beginnings of the Frank Zappa look there, Dude! 🙂
With triple-supply DRAM (4116's) in there, you would probably be better off making the -12V come on first. The 4116's don't like not having the -ve bias up when the +ve voltages are applied.
yep, if the -5v line isnt present when the other 2 come up, they can pass heavy current and be damaged , this happens a lot in zx spectrums with dc-dc converter issues
Love this little brother !!!!!. Any chance of emulating the hawk for this machine using a HW of some sort. You have very smart guys behind this project
Look at the datasheets for the devices that use multiple supply voltages and check what is recommended for power sequencing.
Uploaded after my bed time, but had to watch. And so happy ut works.
I bet you could get a 60 Hz signal from the mains by using an optocoupler like PC817. As a bonus, the corresponding circuit would actually be much simpler than 555 oscillator.
And more accurate. The 555 isn't temperature compensated or anything, so even if it was dialed in precisely to 60 Hz initially (and it wasn't, so...), any change in the local environment can cause it to drift a little one way or the other.
I mean, I get how simple the 555 approach is and I can't argue with that. But it's about the least accurate way to provide the necessary clock signal. There are many other options that would be better, from an accuracy standpoint (even if not expediency).
Coolest thing you’ve built IMO, love how it looks!
I haven’t caught up on the vacuum tube computer yet though, so I’m not saying this is better if that makes sense haha
Maybe some broad shrink tube on the flat cable holders.
Core memory. Sounds tempting. Sounds *very* tempting actually, he-he. I wonder if.......
Nah.... Or...... Well.... I bet one day...... Yeah. With core memory.
Delightful episode. There's just something with these more or less 300 Baud speed text based systems. It's like you can feel the data coming through the wires. Immensely satisfying.
One small thing to check, because you're (hopefully) going to be using this for years you might want to think about putting inrush current limiters in your +-12v lines.
When the relays close any capacitors on those lines are going to get hit pretty hard as they try to charge limited only by their internal resistance. I'd hate for you to power on at an event then blow up an old cap.
You can get little disk type inrush limiters but I'm not sure what the load is on your supply if they will be up to it. Similar idea to your soft start circuit on the tube processor but running in a fraction of a second instead of a fraction of a minute ;-)
Nice job!
Awesome. Simply awesome.
Very well done, indeed! I think it's a very interesting system, would love to play with one some day.
Please wait, beard loading. ;) Loving your stuff mate.
This was a cool build.
Rather than the 555, you could get your 60Hz signal from a very small AC transformer connected to the mains, but with a low voltage output. Then it would be guaranteed to have the correct number of cycles per day form the power company.
Just for the fan pun I hit the thumbs up! Nice work brother, looks good from here. I think your videos are great and your a wealth of knowledge so keep up the awesome work and have a great day.
I'm glad someone caught the fan pun, I laughed to myself quite a bit when I said it while recording the voice-over!
Thanks for the kind words on the videos, it's awesome to hear you're enjoying them!
Love Your work!!!👍
Absolutely awesome job !!!!!!
You might be able to find a nice replacement CRT for that terminal too. That burn in is pretty serious. Refurbishing those would be fantastic too.
That's definitely something I'm keeping an eye out for, because the CRT in there is definitely tired!
@@UsagiElectric May reach out to Adrien from Adrien's Digital Basement. :)
@@UsagiElectric I have a Compaq 286 Luggable with Monochrome plasma screen and detachable keyboard. The idea of finding something like that with (non standard display parameters!) a surround bezel in Centurian colours and a wander keyboard of any kind really would be fun. Our DEC computers at college had Newbury terminals because they were cheaper than DEC
I hope you can come to VCF Midwest this fall and bring this! I hope micro-mini computers become a thing. Imagine a desktop Digital PDP system!
Next project: Pull out an FPGA and make a Centurion-on-a-chip without emulating it?
That's fantastic. It looks great and it works. Best of both worlds. My projects are either one or the other, seldom both. (sometimes neither LOL).
Good luck at the show. :)
nice job
For the color you could do color matching , paint shows do color patching.
2:22 wait now you're a magician too? :0 Took me like 4 replays to figure out where that pencil suddenly appeared from.
Speaking of library’s this kind reminds me of MVS datasets. However with datasets you have extended space available so when it fills up it will consume a new track each time it overflows.
Some semigloss clearcoat would make the wood look a lot nicer.
Nice!
Please record a video for us from the convention!
Great dopamine boost as ever!
You could have used a 4-pole relay and just used 2 power switches to turn the unit on, one for the AC and one for the DC once the power-supplies stabilized.
Did you ground the mains switch body?
The Centurion Veles (because it's light [ish], portable[ish], and veles goes with centurion) build came out well. I wonder how difficult it would be to modify the stripped down OS to use the memory card a bit more and speed up operating time.
please record a video at the event! I'm far too far away to visit it, otherwise i'd be there!
I tried making something like this.
I had some scrap styrofoam pieces, in symmetrical shapes.
I made it look like some sort of crt.
An Ipad or screen could fit in the one styrofoam piece, what had a square opening.
The back of the styrofoam tv, has to parts that open up.
Take some tools with you; surely something will shake apart during the journey :)
I would go another way. Take tools, yeah, .. .but because there will be folks wanting to look inside some cool stuff, with "open brain Centurion" , . . if it is possible ., . I know I would!
God speed ..
Absolutely planning on taking a ton of tools with me, as well as backups of nearly everything!
Is the Centurion terminal standard RS232? It looks amazing. I like that console look.
Yup!
It's an ADDS Regent 100 terminal and uses just plain jane 9600 7-E-1.
I realize this is all after the fact now, but if memory serves me correctly, the @JX files are the JCL command files, @TX are the transient files, the OSEG files are I believe chunks of the operating system executable code, the IOD files are likely the IO driver executables. Like I said, "if memory serves me..." it has been over 40 years since I worked on those systems.
Next step is installing a solid state drive.
If it weren't for the fact I live in the UK - I'd be there JUST to see the Centurion
Why not a single +5 +12 -12 combo PSU, hell why not just an ATX PSU?
This seems way overboard on complexity, although bonus points for using MeanWell, very good PSUs.
Connecting the ram card to a microcontroller to do ram testing would be a fun project. Shame i am in the UK