Linked by intric8 on Tue 28th Mar 2017 20:59 UTC
Amiga & AROS

The Amiga has what is with no doubt in my mind, the absolute finest sound chip inside of any computer or console throughout the 1980's as well as most, if not all of the 1990's. Full disclosure; I have an MT-32... And the Amiga can actually do a piano. Yes, in a time when the vast majority of IBM and compatible PC owners were using a small speaker stuck deep inside of a metal tomb, Amiga users had a quality of sound nobody else could touch for that price.

[...]

To combat the story that has long been shaped that the Amiga was not popular to musicians because it did not have built in MIDI connectors I give you this quote given directly to me from the creator of the sequencing program Music-X, Talin:

"The story with MIDI is actually much more complex than most people realize. You see, the early Amiga models had a hardware bug which made the serial port unreliable at high data rates. Basically the problem was that the serial port hardware had only a one-byte buffer, and if you didn't grab that byte before the next byte came in then data would be lost. Unfortunately, the Amiga's four timer chips would generate a software interrupt at regular intervals, during which time the serial port could not be serviced. And while MIDI speed wasn't super-high, it was high enough that you'd get a dropped byte every 10 minutes or so depending on how many notes you were sending over. Note that this did not affect the higher-end MIDI adapters which had their own dedicated serial point, but those were considerably more expensive."

Interesting article about past MIDI challenges with the Amiga and how to hook up a modern synth to an Amiga to make music.

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RE[2]: MIDI == Atari ST
by Earl C Pottinger on Wed 29th Mar 2017 01:21 UTC in reply to "RE: MIDI == Atari ST"
Earl C Pottinger
Member since:
2008-07-12

I get what you are saying about the interrupt, but I bet the various DMA channels that the Amiga had could also throw off the timing at lot more.

There was a lot of things going over the memory channel.

Edited 2017-03-29 01:22 UTC

Reply Parent Score: 1

RE[3]: MIDI == Atari ST
by JLF65 on Wed 29th Mar 2017 02:29 in reply to "RE[2]: MIDI == Atari ST"
JLF65 Member since:
2005-07-06

That's why I mentioned 16-color hires display - that used all the ram access slots on the chip ram for DMA, so if you tried to access chip ram during an active line, the cpu would be held until the line was done. Good high-speed serial was easier with fast ram, but you still had to be careful about chip ram accesses. You'd really want to make the display no more than 8-color so you'd have half the access cycles available for chip ram.

Four color would be even better, especially since we're just talking about a music editor, not a game or graphics editor. But again, see what you have to keep in mind while doing serial on the Amiga? It's not rocket science, but it's still easy to do SOMETHING that makes missing bytes occur randomly with fast serial.

Reply Parent Score: 2