Posted: 10/1/2017 11:03 PM
Post subject: PSX load times
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arkazal
Joined: 4/17/2017
Posts: 25
TAS-capable emulators have a heavy emphasis on accuracy, which I love. We have emulators that are so accurate for consoles like NES and SNES that we can create something like TASBot and play input done on emulator back onto a console and it works! What about PSX though? For older consoles, the load times are obviously identical; if they were off by even one frame anywhere, the movies would desync. But a PSX uses a laser to load from a disc, and the laser has to move. Does Bizhawk somehow emulate even that correctly, or is that a silly question and there's no way to do that? I guess my question is "could there ever be a TASBot for PSX?" but my curiosity is not so much geared toward TASBot (though I find it interesting), but just accuracy in general.
Posted: 10/1/2017 11:18 PM
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natt
Editor, Emulator Coder, Site Developer
Joined: 5/11/2011
Posts: 1108
Location: Murka
Bizhawk does a reasonably good job of emulating CD load times. Due to the nature of the problem, it's impossible to get perfect. A TASBot would be unlikely to succeed on any game that polls the controller during load screens.
Posted: 10/1/2017 11:35 PM
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arkazal
Joined: 4/17/2017
Posts: 25
Right, I see. It's as I thought. If I compared recordings between Bizhawk and a real PSX I bet I'd be impressed by the similarity. Thank you :D
Posted: 10/3/2017 4:09 PM
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smellyfeetyouhave
Joined: 5/4/2016
Posts: 67
natt wrote:
A TASBot would be unlikely to succeed on any game that polls the controller during load screens.
If I remember correctly, Dwango mentioned during the Harvey Relief Done Quick stream that they were attempting to rig up an SSD in place of a disk drive on a Gamecube to get consistent load times allowing for console verification of Dolphin made runs.
Posted: 10/4/2017 1:57 AM
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Sappharad
Joined: 3/11/2012
Posts: 149
Location: WI
Even SSD presents a problem unless there's firmware to control the timing of it. There are quite a few drive replacement projects for various CD based consoles now. I have one in my Dreamcast, which brings with it wonderfully improved load times. (But it has the ability to restrict to the original speeds via a setting) Even there it's not 100% predictable because the random read times on the flash media aren't 100% consistent. That could probably be accounted for in firmware of a drive simulator though, just have a consistent algorithm to decide the timing of various responses and if the medium you're reading from isn't ready in time too bad, fail completely.
Posted: 10/4/2017 6:13 AM
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creaothceann
He/Him
Editor
Joined: 4/7/2005
Posts: 1874
Location: Germany
Why an SSD if you could perhaps load an entire disk image into RAM?
Posted: 10/5/2017 12:15 AM
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zeromus
Editor, Emulator Coder
Joined: 8/7/2008
Posts: 1156
SSD doesn't present a problem, because an SSD is faster than a CDrom in every possible case, even if it's jittery. All you need to do is buffer it to be as slow as an ideal CD