Right? It shows how easy it was to make a PC clone.

It's the most EDS thing that EDS could have done, lol.

Honestly, I'm surprised they didn't just go that way anyways. The IBM PC was almost entirely built of off the shelf components anyways (78xx logic and a few PLAs), and the clone market was just starting to spring up. They could have made a killing, and maybe stayed around a bit longer.

@@BlackEpyon It does look like the Compaq PC before Compaq built the desktop one.

@@BlackEpyon Well IBM actually used the original Intel reference design, and built it exactly like that, so cloning it was easy, it was an Intel computer system, and provided you bought the Intel support set with the processor, you had an automatic copyright to build the reference design. The most difficult thing was the IBM BIOS, but IBM published the BIOS code entry and exit specs, so anybody could build a clone provided they had a BIOS that followed that code entry and exit strategy, and not get a lawyer dog on them. Though many simply went and copied the IBM BIOS, and simply went and did a search and replace of IBM with their own 3 letters, and changed a few copyright strings to either spaces or null characters, and those figured they would sell a few thousand before big Blue found out, and they could close shop, move to another address, and open up as a new clone seller again. Plenty of clones like that were around, basically using the same exact board layout and components, just the silkscreen changed every few months to reflect a new company name instead. Same artwork for the copper boards all the time.

Fascinating. I never worked for them but I knew people who did and I was familiar with their prominence in the DC area govcon scene. They had an excellent reputation and the most professional project manager I ever encountered was trained there in the mid 1990s. It seems hilarious to me, though, that they made desktop hardware for a while. It would be the modern day equivalent of someone like Booz Allen introducing a smartphone. Or imagine if Palantir came out with a smartphone - that would be even more laughable, for obvious reasons.

I was with EDS for more than 20 years - I never saw one. I supported GM and all I saw ( in pc market ) was IBM - and 1 compaq. I saw one of these at the Toledo Ham Fest ( once a year flea market - SUPERSIZED - blocks in size ). I wondered if it was my EDS or someone else who used that logo. Now I know.

Whoa, interesting! Were they the same style PC as this, or were they a newer type of PC? I'm sure EDS took more than one crack at making a PC clone in its history.

@@UsagiElectric It's been over 30 years, and I don't remember ever looking at the back of the PCs. But the ones that I saw looked exactly like yours in the front. My location at EDS in 1988 was sort of a "backwater", so no doubt that we got cast-offs from other locations.

I started working for EDS in the Netherlands in 1999 and remember seeing one of those exact PCs in the EDS "museum" display case at the Spijkenisse datacenter.

That makes sense! I never thought about the single line being used for adjusting the white balance!

I worked in my father's shop. The way to adjust is to go into service mode for that horizontal line. Turn all colors down until the screen is dark. Turn one color up until you can see it, then slowly turn it back down until the line disappears. Lather, rinse, repeat for the other two colors. That's all it takes to make a good grey-scale.

Specifically, that single line mode disables the vertical deflection (so, don't keep it on in that mode for any length of time; as the entire screen's worth of electron beam(s) is hitting that single line of phosphors). I'm not an expert, this is just from watching old TV repair videos on KZfaq.

Another possibility is that the single white line is used to set the convergence of the R G and B guns. When all three guns are aligned perfectly you would get a crisp white line.

@@nzbsgfan That doesn't work for the vertical deflection; in all the videos I've watched the convergence is setup using the grid test pattern. Again, though, my knowledge is only from watching KZfaq, so.... 🤔

Not just any IBM clone, a Centurion IBM clone!

@@UsagiElectric how can you copy infor from the clone copies to a centurion , for execution, or storage, using the comms programm ?

@@UsagiElectric I heard that in the posh English TV advert voice for MnS. Not just any food, this is MnS Food.

@@highpath4776 So, we can't yet. The Centurion was never really intended to interface with... well, anything. The PC has a pretty good serial transfer program, so we might be able to write some custom software for the Centurion's OpSys that can receive, but we have some big hurdles to overcome to do that. Most notably, the PC will send things in 512 byte chunks, but the Centurion uses 400 bytes per sector, so moving data around gets real confusing. But, that's still something that I want to try to tackle someday!

This will be the fifth video on PC clones I've watched this week.

It physically hurts me whenever I hear about that place, because I didn't have the resources to go there when it was open to the public. And MAN did that look like a good time...

It was a fun 3-year project to empty it and get all that gear out to new homes. Volunteers get together from time to time when we can. :)

@@sterlingphoenix Same.

​@@sterlingphoenixSame here.

I managed to get there two times. The second time I went was only about a month or two before they shut down for good, and honestly, by that time, almost everything of note had been picked. The stuff that was left was either fairly common or in such sad shape that it was really repairable. The first time I went, I should have taken a bigger car with me though, they had some really awesome stuff that I was planning on getting on my second trip, but alas, I was too late.

I wonder what the owner was thinking when hoarding, did he knew that the stuff he has is rare, did he sell what he had when he was alive? I am glad that at the end a lot of things got into a hands of people that wanted them

@@Veso266 He knew what he had and loved to chat about the PCjr.

Please save some vacation days and drive out to Edgar Digital in Las Cruces and visit with Roger. Ask him about his Mercury and Apollo collections and enjoy digging through all the vintage electronics, test gear, industrial gear, and computer gear going back decades.

@@Arcadecomponentscom i do wonder when did his hoard get everywhere At first it seams there was some order, but at the end the whole wearhouse and his house was totaly full, (I saw this on lgr video i believe) What happened so that order was lost and all the stairs and all living space was filled I am a hoarder my self but my hoard is in the closet hidden away not to be in the way of my movment My grandfather has it the way usual hoarders has it (stuff everywhwere so crammed u can bearly move)

Or the 225. I ran a BBS on four 225s for a few years, man they were loud.

While the 10-1000mb hard drives of yore are largely getting grumpy these days, it's worth giving them a whack to see if they'll behave at least One More Time, with a plan for recovering anything of note. Those noisy whirs, clicks, and clacks are the sound of it thinking.

Do you know the RLL data doubling trick? Buddy of mine did it to an RLL drive back around 1990 or so, but you change the crystal that sets the data clock and you can just about double the capacity of the native drive. One the Seagate's we found that only going to about 60 percent larger was stable. We even threw Super Store at it and doubled the data through compression on top of it, but that really worked the drives. Not going to lie, I hated those 'SeaScrape' drives, always had problems (crash or bearings died) where the Western Digitals and Uniscribe drives seemed to hold up much better and never die. Man does this bring back memories.

Does the floating leg always get pulled high if the non-floating leg is pulled high? I thought you had to bridge together the inputs of an AND gate to make it a buffer.

@@rich1051414 In my experience that depends on who made the 74LS08. Midway made a series of arcade game boards where they left some tied high with a resistor and left others open depending on the maker of the chip.

I think you might be thinking about OR, it would be a buffer if you did that. I think cutting the leg means the output is always low, whereas cutting the output would leave a floating line to a possibly more sensitive IC.

@@rich1051414The original 7400 TTL series inputs naturally float high and require substantially more input current to pull them low due to how they are constructed with bipolar transistors. Early on this was an important difference in properties between bipolar and MOS logic even when their logic voltage levels had compatible overlap.

@@teknifix That depends on whether or not the cut leg floats high. If not, then you're wrong. If it does, then you're right.

74ls20 ?

@@rallyscoot No, a 74S00. The '00 is a quad 2-input NAND, and the '20 is a dual 4-input NAND.

We used to have two banks of ram and eprom's as their access times were not fast enough for the 8080 (i think that was the chip but could be wrong). So one set of ram / eprom on even address and the second on the odd address, this effectively halved the speed of the bus. Added an extra step in programming the eprom's as as you had to strip the data for two eproms before you could program a software change in to them. this was done on a micro vax system. :-)

Weren’t there scsi scanners?

@@ppokorny99 yeah, they were a thing too, either would make sense for access to the vmem but i would guess its intended for a digitiser

@@mycosys early HP Scanjets used a scsi interface

Ah nice I came here to say this too! People forget that SCSI was designed as a generic device bus, not just for disks.

At this point, scsi portion of the graphics card was used for scanners but eventually supported first generation CD-ROM readers.

Please, only one comment instead of 10 million

Excellent! Looking forward to maybe getting some data off the old girl!

I love the sound of those old Seagate drives! I had the ST-238 in my clone, a thin WYSE PC that I wish I never gave away...

@@stanb1455 that was only one comment, sequentially on the HDD, nice and easy to follow

@@volvo09 I think a WYSE ? terminal passed through my hands once in the UK too

That's it! Those things are so weird looking. Wild that they would print the resistors onto the ceramic substrate and then solder on IC components. What a wild way to build stuff!

@@UsagiElectric Not really weird, this is still common in high reliability applications, and where you want to have precision resistors in an application, and do all the trimming and calibration during manufacture, and have zero setup needed on the line, or during repair, as each module is laser adjusted during production to be identical. Your multimeter uses this for the thick or thin film resistor array that provides the voltage selection, and also it is common in things like terminators, where you can get a precise production of a complex part with simple silk screen printing. Very common in military equipment, and also the method used to build the LNB that your satellite receiver uses, as a reproducible part that is both stable and precise, and which lasts well under extreme temperature swings. You also will find it used in pretty much every sensor in your cars, and in the voltage regulator modules on the alternator, as a way to get a robust reliable package for the electronics.

@@SeanBZA You also find them in a lot of retro kit, the Amiga 500's video output hybrid jumps immediately to mind (basically an R-2R ladder DAC with some driver transistors).

@@SomeMorganSomewhere Yes Burr Brown used this to make ultra precise units, where you would have a 24digit DAC that would not skip codes and be monotonic over the full -55 to +125C military temperature range, as the resistors all track each other precisely. Once factory calibrated, and sealed in a metal case with another thin film to do the reference voltage, they would never drift.

Thank you so much! I'm fascinated by the RS-232 protocol, it's been around for something like 60 years at this point, and as long as you get the settings right, it just works. It took me less than 30 minutes to the get the EDS PC plugged into the Centurion with a custom cable and functioning. I can totally see why the concept is still being used today!

The latency from Mars to earth is of around 8m30s, that's a long while

If you go to mars, you’ll have to bring your data with you….an AI database! Get a daily digest from earth, send a daily digest back.

Does that mean David might be able to get a technical description of how to create the bona fide Centurion blue color out of RGB's dusty old files?

It was so cool to see that in person, I had no clue it was there!

@@UsagiElectric I did a double take when I saw the colour palette! The monitor label shows "32 colors can be selected from 4096" at TTL levels. It says 3 lines; presumably 8 color RGB, 4 lines; RGBI CGA, and 5 lines; for the 32 color mode. So it's not EGA which uses 6 lines and a fixed 64 colour palette. What video card can drive the 5 line 32 color mode? And does the monitor have built in functions for selecting your 32 colors from 4096 possibilities? I've never seen anything like it.

@@erikj3390 yeah. Mindboggling. Suppose there was something like a programmable palette table in the monitor? In principle you could display Amiga-like graphics on there. But without a clock line, it seems difficult to imaging how you'd avoid really weird fringing effects.

@@erikj3390it's basically the Amiga palette. 12 bit RGB... even the 32 out of 4096 matches with the Amiga. :)

I wonder if they'll let me in to wander around, lol.

Haha well chicken nuggets are important too

@@UsagiElectric Well hard to say, but you might get in, and still see remnants of the plant there, though the office space likely still closely resembles the original, aside from having had a dozen remodels over time. Go to the power inlet and you probably will find Centurion branded equipment panel plates there though, or at least on the city engineering plans. Those drawings and plans are never updated name wise, because they get referred to by so many other plans, so keeping them in sync is near impossible. By me there are still substations where the plans refer to the original builder, even though the building has changed hands over time, the substation and power rooms, plus telecoms rooms, all still have layers of old names around. Worked in a building which was called Olivetti House, but they were long gone, and the substation in it had feeds from House of Delegates (now dept of education), and off to Forsdicks Motors (now a part of VAG dealerships, as Forsdicks moved out a half century before), and another feed marked as Receiver of revenue, which is still there, though they now occupy 4 buildings instead of 1 as they rebuilt over time from a tiny extra to being the main office. Another town the substation says Roberts Heights, with later feed additions saying Verwoerdburg ext 2, and latest now saying Centurion ext 4, and they still are the only block of substations that supply power at a nominal 250VAC, as opposed to the later standard of 240VAC, and the new harmonised standard of 230VAC. Incandescent lamps, stoves and heaters have a very short and very bright life there still, peak voltage of 263VAC and minimum of 226VAC, barely within spec, and almost always running on the high side around 245VAC. But hard to change because of the LV and MV interconnects you would need to do all at the same time to fix it, and change all the transformer taps same power interruption, so they simply set new transformers to the same voltage settings. Only new developments, with a single 11kV 3 phase supply, got 230VAC mains fed to them, the old layout with parallel transformers in a ring stay the same.

The question is ... and perhaps Mr Usagi can do a first here. Eat some Pilgrims' Pride chicken nuggets in front of a Centurion terminal. I mean, the most complete computer restoration action would be to remove food particles made in the same factory as the computer. How many times in history has that been done? How many times has it knowingly been done? HOW MANY TIMES WAS IT RECORDED, AND POSTED ON KZfaq?

Centurion had 1780 Jay Ell built-out for our company from the shell building to our spec in 1978-1979. After Centurion then EDS-Centurion the Centurion line was sold to ZTRON and we moved the temo site in Richardson before moving to a new building in Allen, TX on West Bethany Dr. After Centurion move out of Jay Ell the building became EDS Tech Products Div ( building stuff for GM ). Later Jay Ell became a Data Center for Ross Perot's new company "Perot Systems". After years of being a data center for Perot System the data center was sold to Pilgrims Pride as a Data Center ( maybe to count chicken parts ).

I enjoyed my time at Centuion-EDS so much I worked at the EDS Plano campus again two more times before retiring in 2017 from old EDS Plano campus now owned by HP.

Ah, the Fujitsu SPARCs.

and SASI was SCSI before SCSI was SCSI. Should be able to actually plug a SCSI-1 drive into that display card, if the pin out is known and can be mapped to the drive.

Indeed, most scanners trough the 80's and 90's were either SCSI or Parallel port, so it makes sense for that. Also external enclosures were also most often SCSI or Parallel.

Yes, and "SCSI" was originally supposed to be pronounced "sexy" but someone said "scuzzy" and it was funny, so it stuck :-)

I still use scsi scanners every day.

Thank you so much!

Gotta represent!

Ryn, there is still hope for the hard drive! (And good to see you here, too!!)

@@ForgottenMachines Good to hear and thanks so much.. :).

It really is a bonkers story! And like Forgotten Machines said, we haven't given up on the hard drive yet!

@@UsagiElectric dismantel and rebuild / or try diff drive and different controller card? the PC community is somewhat bigger than the "Centurion" one so sourcing replacements or alternatives less problematic

@@UsagiElectric Judging by the noise alone, that drive is working 100%. I don't know what kind of tests you did on it; if the computer doesn't see it, it might just be a bad connection.

tend to agree - as at the end you heard it do a full seek without hitting the mechanical stop.

It should be backed up before wiped over so carelessly.

Thank you so much, glad I managed to get the pacing right!

The logo and font really reminds me of the text paper found inside my magnavox rgb monitor. It's got a similar feel.

He picked that up from Adrian's Digital Basement, who picked it up from LGR I think? The app is called Spectroid, it's been on my phones for like a decade.

Ah, that would make sense! I didn't even think about it being an official bodge, I was thinking someone along the line somewhere had modified it.

It might be like a dog lifting its leg to mark its territory .... ?!

I suspect you are right. Not much else makes sense. From memory, 74LS08 is a quad two input AND gate. Pin 2 is lifted which is input 1a. Pin 3 is input 1b and pin 4 is the gate's output.

Updated the description with the link! (Thanks for reminding me, I totally forgot, lol)

that logo looked like RCA, which had Japanese partners.

The monitor's construction is really crazy too. Nothing like you'd see from Japan: more like some mil spec high reliability thing. The motherboard on the other hand, stuffed with Japanese ICs a North American manufacturer wouldn't have used at the time, has to be Japanese. I see Mitsubishi, NEC (CPU even!), Toshiba, Hitachi. A couple National Semiconductor UARTs and 8088 support chips but probably because they had no other choice.

I think one of my favorite things about the Centurion story is that it's really similar to so many other stories out there of small computer businesses. It was the wild west, and people were pouring their heart and soul into this new and exciting industry, and so many of those stories have been lost to the sands of time. But, I think those stories are not only fascinating, but important to remember. They can teach us so much, both from their successes and failures!

Looking at the SN74LS08 schematic, that input will float high turning it into a buffer im pretty sure. Its a ground triggered schottky input

@@mycosys ah, OK - it has diode input, it'll go low only when one or more of the inputs are pulled down. Leaving them floating will force high on the output.

@@KeritechElectronics Thats what it looked like, yeah.

Makes it easy to reverse-engineer too, which is important if you can't find a schematic anywhere.

RLL drives needed a better quality of magnetic platters to be reliable. I had both MFM and RLL drives back in the day. I had software that tested hard drives at a low level (spinrite and disk technician) and reportedly you could take an MFM drive, connect it an RLL controller and get 50% more storage after testing and validation to detect bad blocks

​@ppokorny99 Yes. Also RLL generally required better performance in the data separator circuit on the disc controller board.

I think they used RG58 like 10base2 ethernet, because of the 50 ohm impedance vs 75 of tv coax...

@@freeculture you may be right, because I don’t recall the coax being as thick as RG 59 was

That's exactly true about the ST-225/ST-238. Although a large number of ST-225s with few or zero defects didn't get the ST-238 label simply because there weren't that many people that could justify the more expensive RLL controller and there were some suspicions that the higher capacity was somehow more failure prone.

RG62 if I remember correctly. This was one of the reasons why some businesses migrated to Arcnet, they already had the cabling for the IBM terminal network.

Same here. I was a little late to the BBS world, as I didn't get a modem until the family business bought a second PC in 1987... and in 1991 all my Internet access was through my college's VAX, so Procomm Plus was constantly running... I even used it under OS/2 in order to test the dial in lines for the ISP I helped start. Never liked the competitor software... and I liked the ability to extend Procomm... like when you had to manually setup bleeding edge software like Zmodem before it became commonplace.

At first I thought of RGB Spectrum (that make video wall equipment) but it sounds more likely that it might be that RGB Display company in Grass Valley ☺

I expect it to be the same as any other XT clone, would be nice to run Checkit, speedtest etc. It should run any XT program/games etc.

Won't the input "float" high, turning the gate into a buffer? Or do the LS series gates either float low or become indeterminate if left floating?

​@@melkiorwiseman5234Unconnected LS inputs float high.