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Thread: Paprium: Official Thread

  1. #9901
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    I think MCD 1's laser assembly is really expecting a 500 MB CD built with a certain medium that nowadays simply doesn't exist anymore.
    My assumption is that the whole system driving it doesn't have enough precision to read 700 MB CDs at all.

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    Quote Originally Posted by Barone View Post
    I think MCD 1's laser assembly is really expecting a 500 MB CD built with a certain medium that nowadays simply doesn't exist anymore.
    My assumption is that the whole system driving it doesn't have enough precision to read 700 MB CDs at all.
    I hadn't thought about this as I had always assumed it to be something different in the BIOS between the different revisions vs something physically different between them.

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    All MCD1 will develop bad capacitors and that's one of the bigger reasons why not all CDs play right or at all. If your MCD1 hasn't seen recapping it needs to be done sooner than later, if the capacitors leaked already you'll eventually have unrepairable machine at hand in future. Same as with Game Gears.
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    Quote Originally Posted by TmEE View Post
    All MCD1 will develop bad capacitors and that's one of the bigger reasons why not all CDs play right or at all. If your MCD1 hasn't seen recapping it needs to be done sooner than later, if the capacitors leaked already you'll eventually have unrepairable machine at hand in future. Same as with Game Gears.
    Ugh, so true. happened to both of my Mega CDs. managed to repair one but the other has a dead board that I just can't get working anymore.
    I wish people would spend less time developing flashcarts and spend some more time creating spare parts for my beloved old machines. ;_;

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    As far as I recall the issues happen even on systems in good shape. No matter how hard you try, those drives were not built with higher density CDs in mind (remember, 600MB ones were the largest ones at the time). The problem is convincing the factory pressing the CDs to not attempt using the tighter pitches that modern discs have.

    And yeah, model 1 Mega CD seems to have some suspiciously high failure rate even beyond just capacitors (apparently the whole thing can die on you hard even if you replace the capacitors and change the laser, not sure what's going on with them).

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    Quote Originally Posted by thesegadude View Post
    I understand why you might think this about Luis. I won't fault you for it.

    I still believe that Luis told us the truth; that he played Paprium on his own original Genesis.
    If so, what's delaying the game's release? I'll be the first to apologise if Luis turns out to have told the truth.

  7. #9907
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    Quote Originally Posted by chilled View Post
    so what is different hardware wise between MCD 1 & 2 that makes some CDs unreadable?
    The MCD1 just has a horrible, unreliable CD hardware. The MCD2 was significantly more reliable.

    I recall there was an interview with one of the engineers, who said that the MCD1 used an audio cd player inside which was in no way prepared for the significantly higher duty cycle and seek count that videogames would subject it to. As a result, some games put so much strain on the hardware that it caught fire. They found out about that, like, a week before launch. Wish I remembered which interview it was, pretty sure sega-16 hosts it.

  8. #9908
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    ^This is the interview you're referring to:
    "The Mega-CD was designed with a cheap, consumer-grade audio CD drive, not a CD-ROM. Quite late in the run-up to launch, the quality assurance teams started running into severe problems with many of the units - and when I say severe, I mean units literally bursting into flames. We worked around the clock, trying to catch the failure in-progress, and after about a week we finally realized what was happening. The specified limit on time spent seeking the heads versus playing a track was 5 per cent. Some of our video-based titles were running around 90 per cent. We were causing the motors in the drives to catch fire."
    https://www.eurogamer.net/articles/2...ga-enterprises


    There's also this by Sega-16:
    One final story…. when I first got hired out of the test department as a tech support guy, my first assignment was to do build a tool to stress test the Sega CD units, which were due to ship to stores in a few weeks. I built a quickie program that would just run the laser head across the CD back and forth for hours at a time, and then see how the motors degraded over time. Unfortunately, most of the Sega CDs we tried this on died after a few hours. I recall setting up a conference room with about thirty Sega CDs, letting them run overnight, and coming back to work to find only two were still running. It turned out that a ribbon cable had a tendency to get caught under bracket in the hardware, and would eventually break, totally killing the system.

    Sega eventually had to hire a bunch of people to open all the Sega CDs that were about to ship, and add a rubber band to each one. Since that was my first actual job as an employee of Sega (I was a contractor when testing), I’ve always found that amusing… I almost killed the initial shipment of the American Sega CDs….
    https://www.sega-16.com/2011/03/interview-doug-lanford/


    And there's also this interview referring to the fragility of the Sega CD dev kits:
    Scot Bayless: I joined SOA as a Technical Director right at the end of ’90 and, if memory serves, we started getting preliminary technical information about Sega CD very early in ’91. All the documents were in Japanese, and the guys in Tokyo just didn’t have the infrastructure to translate them, so we started hiring local translators just to get caught up on the docs. The first breadboard dev kits started showing up early in the spring. They were huge, fragile beasts, sensitive to electrical noise and prone to random lockups, but that’s the nature of prototype systems. By summer, we were in full burn, trying to get both our internal titles and several key external projects up to speed. That left us only a few months to launch; it was nuts. We literally worked around the clock all the way up to the launch in New York.
    http://www.sega-16.com/2012/03/interview-scot-bayless/

    Matt Phillips (Tanglewood) has a Mega CD 1 dev kit which also gave him lots of headaches with maintenance.
    Last edited by Barone; 09-10-2019 at 07:41 PM.

  9. #9909
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    The PC Engine CD experts who figured out how to successfully press new CD games have said that old CD-ROMs can read higher capacity discs well enough. It's all about how the disc image is setup for the target disc format.

    The Pier Solar disc probably didn't receive much fine tuning and once it was working on one Mega-CD setup it was considered good to go.

    As with cdr copies of games, once a bunch of random people start burning cdr discs using random software and burners, there's no way for the results to be consistent.
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  10. #9910
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    Quote Originally Posted by Black_Tiger View Post
    The PC Engine CD experts who figured out how to successfully press new CD games have said that old CD-ROMs can read higher capacity discs well enough. It's all about how the disc image is setup for the target disc format.

    The Pier Solar disc probably didn't receive much fine tuning and once it was working on one Mega-CD setup it was considered good to go.

    As with cdr copies of games, once a bunch of random people start burning cdr discs using random software and burners, there's no way for the results to be consistent.
    Just for clarity though, Pier Solar's CD would actually start to work perfectly for most people, once they burned a CD-R copy of it. So in this case, that WAS the consistent solution. (I'm also not very convinced that burning CD's causes so many random problems, as many people think... but that's a tangent.)

    I don't think we ever figured out exactly what the root of the problem was, for Pier Solar's printed discs... but the solution sure was easy enough.

    Maybe some quirk with how the official discs were printed or something. IDK how it makes sense that a simple copy of the same disc could suddenly work perfectly, while the original won't...

  11. #9911
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    Is there a source for the drives being limited to 500 MB? I've seen this posted countless times over the years but the Yellow Book (ISO/IEC 10149:1995) was already finalized in the late 1980s when 74 minute audio CDs were standard. Even in Mode 1 (which uses extra bytes for error correction) you still get 2048 bytes/sector for user data and 333,000 sectors for 650 MB.

    The only reason I can think of for a 500 MB limit is if the Sega CD hardware can't address anything higher than that. Coincidentally in the early '90s there were computers where the BIOS couldn't see hard drive data past 504 MB without an overlay for geometry translation but I see no reason why something like a CD-ROM would ever be made that way.

  12. #9912
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    I think the 500mb limit came from SEGA docs. I don't know the actual reason.

  13. #9913
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    Quote Originally Posted by axel View Post
    Is there a source for the drives being limited to 500 MB? I've seen this posted countless times over the years but the Yellow Book (ISO/IEC 10149:1995) was already finalized in the late 1980s when 74 minute audio CDs were standard. Even in Mode 1 (which uses extra bytes for error correction) you still get 2048 bytes/sector for user data and 333,000 sectors for 650 MB.

    The only reason I can think of for a 500 MB limit is if the Sega CD hardware can't address anything higher than that. Coincidentally in the early '90s there were computers where the BIOS couldn't see hard drive data past 504 MB without an overlay for geometry translation but I see no reason why something like a CD-ROM would ever be made that way.
    There were definitely 63 minutes/550 MB CDs back then.

    By the way, the document you cited is literally from 1995 as stated in its code.

    The difference between 63 minutes, 74 minutes and 80 minutes CDs is the number of sectors; sectors are 2 kB each.
    1x drives such as the Sega CD are supposed to transfer 150 kB/s which is equivalent to 75 sectors.

    Also, see this:
    http://www.sega-16.com/forum/showthr...60-CD-ROM-Data
    Last edited by Barone; 09-10-2019 at 10:50 PM.

  14. #9914
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    Quote Originally Posted by Barone View Post
    There were definitely 63 minutes/550 MB CDs back then.

    By the way, the document you cited is literally from 1995 as stated in its code.

    The difference between 63 minutes, 74 minutes and 80 minutes CDs is the number of sectors; sectors are 2 kB each.
    1x drives such as the Sega CD are supposed to transfer 150 kB/s which is equivalent to 75 sectors.
    Yes you are right it is a revision of the 1989 document, unfortunately I don't see the original freely available. I guess I'd have to find the original version but I'd be very surprised if it didn't include the 74 minute capacity since that was so common even back then.

    I remember 63 minute CD-Rs for early CD burners but never heard of that being a limit for CD-ROM drives.

  15. #9915
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    I just assumed 500MB was a typo.

    Just checked and the Sega CD docs state… conflicting limits. At points it says 60:04 and at points it says 540MB (though the exact amount really depends on whether it's an audio or data track, due to the latter having more error correction). I'm not sure if it's really enforced by the BIOS or if it was Sega trying to cover up their asses in case some large disc was unreliable (the docs also bring up 20 minutes discs, which I suppose are minidiscs?).

    The CD controller itself isn't the issue, since if you try to by-pass the BIOS and use it directly, it'll happily take some absurd timestamps with no problem (and it lets you reach some areas that are apparently hard to access with common CD drives on computers?). I have no clue how it reacts to multisession discs though (as it predates them by a few years), and I know some badly mastered discs would have a separate session for every single track.

    …how many tracks does the Pier Solar disc have?


    EDIT: for the sake of trivia, the LaserActive apparently is also like that and it also applies to the laserdisc-specific stuff (oh boy) and Nemesis had been using it to make dumps of laserdiscs in general. Supposedly the LaserActive is a low-end drive as far as laserdiscs go but it seems to be surprisingly good for dumping :​P

    EDIT 2:



    EDIT 3: OK I see how they got to the 540MB number… 60 minutes worth of data is 540000 KB (・_・)
    Last edited by Sik; 09-11-2019 at 04:20 AM.

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