Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!ccu.umanitoba.ca!herald.usask.ca!alberta!ubc-cs!uw-beaver!mit-eddie!media-lab!snorkelwacker.mit.edu!hsdndev!rutgers!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.datacomm Subject: Re: 19200 baud amiga Message-ID: <19303@cbmvax.commodore.com> Date: 25 Feb 91 22:48:41 GMT References: <2587@tmiuv0.uucp> <978@faatcrl.UUCP> <19116@cbmvax.commodore.com> <1022@faatcrl.UUCP> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Distribution: comp Organization: Commodore, West Chester, PA Lines: 50 In article <1022@faatcrl.UUCP> jprad@faatcrl.UUCP (Jack Radigan) writes: >daveh@cbmvax.commodore.com (Dave Haynie) writes: >>The real problem with high speed serial input is buffering. > True. Is there any consideration of a FIDO, or at least one additional >byte of bufering being considered for a future PAULA? Certainly a FIFO would be a good idea; they worked fine in the system level chips like the DMAC. Either a decent FIFO or a dedicated DMA channel like the floppy gets would solve the problem. >>On the other end of things, if you're running a packet oriented protocol, >>rather than single characters, you can get a reliable Amiga-Amiga connection >>going in the 150KB-200KB range. > But this would mean bypassing the serial.device and going straight to the >serial.resource, right? What impact does this have on the rest of the >system? It slows the system down when you're running a transfer, same way any other polled-I/O transfer slows the system down. >>In general, the DMA devices won't be a problem. > Nope, check that. Certain Supra DMA controllers completely stomp all over >ZMODEM downloads @ 19.2kbps if the transfer is done to disk. You sure that's one of the old Supra DMA controllers, or is it their new one, the non-DMA "WordSync". If their DMA controller is causing problems, they're doing something evil. No DMA device should tie up the bus unless it has data to transfer immediately, and no single hard disk can keep a DMA device device's FIFO/buffer full for long. Polled I/O devices, on the other hand, are something you would expect to see problems with. > While I may have been mistaken as to the cause of the problem, there *is* >a definate interference with certain controllers and serial input. You can _always_ make a piece of hardware that causes a problem. We spend lots of time working out ways to not cause problems with the built-in stuff, at least. I wish they had considered this problem with the original Paula, but I guess no one's perfect. They got the rest of it right... > -jack- -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett