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Does anybody know and has time to explain why emulators cannot play this demo? I always assumed emulators recreated the hardware in software, so why won't they

Does anybody know and has time to explain why emulators cannot play this demo? I always assumed emulators recreated the hardware in software, so why won't they be able to do something the hardware could?

Scali 8y ago
In theory emulators recreate the hardware in software. In practice, emulators approximate the hardware in software. In the case of PCs, there is so much hardware variation, that it was never a requirement to be very accurate in terms of speed, unlike machines such as the C64, Amiga, Atari ST, NES and various other machines, where many tricks found in games and demos depend on manipulating specific hardware registers in very specific timeframes. This demo has various effects that depend on the exact speed of the CPU and hardware. No PC emulator is anywhere near that accurate, leading to effects not working correctly, or just hanging altogether (eg the end-tune depends on instructions being in the prefetch-buffer at a specific time). Another issue was the 1k colour effect, which exploits the way the NTSC signal is generated. Most emulators didn't emulate NTSC composite very accurately (just treating it as a 16-colour mode). The timing in this demo is so critical, that even most clones with an 8088 at 4.77 MHz and a CGA-compatible clone card do not play the demo correctly.
- zellyn 8y ago
  OpenEmulator, a little-known emulator for the Apple II, has an absolutely fantastic NTSC emulation, done with GPU shaders. I'm in the process of porting it to WebGL, so that (a) I and others can actually understand it, and (b) so that others can use it.
Aissen 8y ago
There's this Ars article on the subject: https://arstechnica.com/gaming/2011/08/accuracy-takes-power-one-mans-3ghz-quest-to-build-a-perfect-snes-emulator/ https://arstechnica.com/gaming/2011/08/accuracy-takes-power-... And an interesting stack exchange question: https://retrocomputing.stackexchange.com/questions/1191/what-exactly-is-a-cycle-accurate-emulator https://retrocomputing.stackexchange.com/questions/1191/what... Edit: very interestingly, if I copy/paste your exact question on Google, it gives me the Ars link as a first result (in incognito mode). I don't think my comment had any influence (too short time to update the index), Google is truly magical.
- gowld 8y ago
  "emulators recreate hardware software" gets good results. The rest of the query is fluff. Adding "cannot" makes the results even better, which is magical.

Scali 8y ago

In theory emulators recreate the hardware in software. In practice, emulators approximate the hardware in software. In the case of PCs, there is so much hardware variation, that it was never a requirement to be very accurate in terms of speed, unlike machines such as the C64, Amiga, Atari ST, NES and various other machines, where many tricks found in games and demos depend on manipulating specific hardware registers in very specific timeframes. This demo has various effects that depend on the exact speed of the CPU and hardware. No PC emulator is anywhere near that accurate, leading to effects not working correctly, or just hanging altogether (eg the end-tune depends on instructions being in the prefetch-buffer at a specific time). Another issue was the 1k colour effect, which exploits the way the NTSC signal is generated. Most emulators didn't emulate NTSC composite very accurately (just treating it as a 16-colour mode). The timing in this demo is so critical, that even most clones with an 8088 at 4.77 MHz and a CGA-compatible clone card do not play the demo correctly.

zellyn 8y ago
OpenEmulator, a little-known emulator for the Apple II, has an absolutely fantastic NTSC emulation, done with GPU shaders. I'm in the process of porting it to WebGL, so that (a) I and others can actually understand it, and (b) so that others can use it.

Aissen 8y ago

There's this Ars article on the subject: https://arstechnica.com/gaming/2011/08/accuracy-takes-power-one-mans-3ghz-quest-to-build-a-perfect-snes-emulator/ https://arstechnica.com/gaming/2011/08/accuracy-takes-power-... And an interesting stack exchange question: https://retrocomputing.stackexchange.com/questions/1191/what-exactly-is-a-cycle-accurate-emulator https://retrocomputing.stackexchange.com/questions/1191/what... Edit: very interestingly, if I copy/paste your exact question on Google, it gives me the Ars link as a first result (in incognito mode). I don't think my comment had any influence (too short time to update the index), Google is truly magical.

gowld 8y ago
"emulators recreate hardware software" gets good results. The rest of the query is fluff. Adding "cannot" makes the results even better, which is magical.