|
Post by turboxray on Jul 4, 2020 17:57:33 GMT
There's nothing "non-standard" about the PCE's CD format. It is yellow-book standard. Just because it's not ISO-9660 layout by default (which can easily handle), doesn't mean it's not yellow book. It is to the T.
Just want to clarify this whole "pre-gap" thing. In CD tracks, there are actually "chapter" markers in the track itself. All tracks require at least one chapter marker, and the minimum it can be is 2 seconds (it doesn't have a maximum). Some "concert" recording CDs actually use this. When you seek to a next "track", it starts at chapter 1, but if you listen continuously from track to track, you'll hear the contents in chapter area 0. This is also how some audio CDs hide hidden "tracks" in the pre-gap or space between chapter 0 and 1. If this is done in the first track, the only way to hear it is to "rewind" into the pre-gap area of the first track.
So yes, they are most definitely required to read data in the "pre-gap". And the data is supposed to be valid (regardless of the mode).
For the record, the dual boot Lords of Thunder disc that I made that runs on both SegaCD and PCECD specifically because of this. The SegaCD (and PC/MAC/ETC) adhere to the ISO-9660 spec that says the starting from LBA 0, CDFS must start at 150 sectors from that point (2 second pre-gap). It doesn't care about "chapters", it cares about a hard offset. The PCE, when seeking a track, always going to chapter 1 of the track (data or audio) like it's supposed to. So the ENTIRE SegaCD ISO is in the pre-gap of the PCE data track, because the SegaCD uses a hard offset rather than chapter offset. I simply moved the data track to first track on the PCE new layout, and hacked the game's audio track table to adjust for that (thus no audio warning track).
If the sectors ARE bad or incorrect in the pre-gap (between chapter 0 and chapter 1) of a PCE CD game, it's irrelevant. No PCE game checks for it. And all track seeks go to chapter 1 of that requested track. A "post-gap" can be chapter 2 of that track, or simple just silence (it's mean for audio players where gamers might accidentally 'rewind' into a data track). It also has no bearing on the PCE directly, unless a game developer was dumb enough to use LBA or M:S:MS direct offset of the CD layout instead of track # to play an audio track. And yes, some early developers did this.
There's no "magic" to the PCE CD format. It's literally just yellow book standard, right down to the mode for the data track sectors. There is a protection mechanism, but it has nothing to do with the CD format, sector mode, etc. It's just a string compare from the data track to identify a data track as PCE game. I.e. you don't want to start interpreting any random data track on a CD as PCE data.. that would be bad. Secondly, probably useful in court at the time to protect against unlicensed developers.
|
|
|
Post by dshadoff on Jul 5, 2020 5:40:25 GMT
Everything turboxray says is all true, assuming a consistent DATA or AUDIO format.
However, the transition between DATA and AUDIO format (or AUDIO and DATA format) is required to be at least 2 seconds, and not defined as being readable. Of course, parts of it are readable on various drives - but this is where CD drives become inconsistent, failing at different locations within this interface area. I recall that in the early days around 1998 there were one or two drives which could read these areas completely, but I haven't seen one since.
But this doesn't normally matter, as the interface area is normally handled as INDEX 0 of the latter track, which is happily avoided during normal use, due to the TOC pointing to INDEX 1. And the fact that no other system (prior to the later multi-session discs) places a DATA track anywhere other than at the start of the disc.
Apologies if I was not clear enough about the details. (Multi-session and other subsequent modifications to the CD standard would make the discussion even more complicated, so I'm avoiding them)...
|
|
|
Post by rcantor77 on Jul 11, 2020 19:28:00 GMT
You are missing the first Super Engine (Shuttle Clone) by Sunpronic...
|
|
|
Post by goldenwheels on Jul 14, 2020 19:08:34 GMT
I have 5 or 6 of the HuGo booties somewhere, including a 4-in-1. I can take some pics and upload if desired. EDIT, here you go. Oddly the puzzle 4-in-1 has a "real" instruction manual, instructions for each game...the other just has a cover art sheet with simple how to use a huey directions.
|
|
retrodave79
What's a PC Engine?
Posts: 3
Fave PCE Shooter: Mr Heli
Fave PCE Platformer: Jackie Chan
Fave PCE Game Overall: Ninja Spirit
|
Post by retrodave79 on Jan 13, 2023 17:27:31 GMT
Hello! I'm trying to find all the bootleg games I had when I was a kid, I have one that I think is not listed: PC KID 2 (HUGO PC SYSTEM) Sorry no manual or PC CARD pictures, game is new and sealed.
|
|
exodus
Punkic Cyborg
Posts: 161
|
Post by exodus on Jan 13, 2023 23:02:51 GMT
Wow, this is cool I've never seen this one! I assume the rom is the same, if you know?
|
|
retrodave79
What's a PC Engine?
Posts: 3
Fave PCE Shooter: Mr Heli
Fave PCE Platformer: Jackie Chan
Fave PCE Game Overall: Ninja Spirit
|
Post by retrodave79 on Jan 13, 2023 23:27:14 GMT
Wow, this is cool I've never seen this one! I assume the rom is the same, if you know? Sorry but I dont know, I've found this game in Spain, someone still has new Galaxy consoles and some bootleg games, as everything is new and sealed I belive he was the one importing and selling them in the 90s. When I got my Jamiko PC BOY in Spain in the 90s I also got some bootlegs (Altered Beast, Mr Heli, Genpei Tōma Den, Ninja Spirit, Splatter House and Jackie Chan), but I can't remember if they have PC KID 2 available. They bring 2 or 4 new games every month, and I was not aware everything was bootleg hahahaha, I even made my mother gift me a Turbografx game just to find out it was not compatible.
|
|