Russg wrote:
<heuser.marcus@freenet.de> wrote in message 408ecbae-5123-4571-81a8-0daf48109f2a@l64g2000hse.googlegroups.com">news:408ecbae-5123-4571-81a8-0daf48109f2a@l64g2000hse.googlegroups.com...On Apr 15, 3:22 pm, "micrologix1...@yahoo.com" <micrologix1...@yahoo.com> wrote:
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I read the article, sorta, up to page 43 or so. I don't know the speed of a Apple ][ floppy, I do know the basic speed was 10 times faster than a Commodore 1541. Seems I remember
Commodore were actually pretty nice drives from a hardware POV. Essentially the same type of built in 6502<7> smart box but with built in power supply instead of wall wart/pig in snake type. They had fast loaders too like we had Warp and USD.
that the Atari can go about 52K baud, which is about 5K bytes/sec. The bus speed of an Atari is 115K cps I think, so that is a limit on its I/O.
Right, derived by dividing the system clock down from the 3.57954 mHz crystal. Goes something like system clock 1.78977 mHz but with a divide by 16 prescaler to 111.86 kBAUD. We have a POKEY register that can divide that down further to get our other frequencies. I seem to recall it is a 16 bit register so we can go pretty slow and accurate the slower you go. Certainly the 1 mHz 6507 we have in our drives would be pushing it to do the timing right at 112 kBAUD!
IMO you are ultimately slaved to just what a 6502 can do. Even a RAM disk is limited to ~25k/sec.
Rick