Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!bloom-beacon!eru!hagbard!sunic!ugle.unit.no!nuug!ifi!torkell From: torkell@ifi.uio.no (Torkel Lodberg) Newsgroups: comp.sys.amiga Subject: Re: USR 14400/V42bs and Amiga Message-ID: Date: 1 Jan 91 17:26:18 GMT Sender: torkell@ifi.uio.no (Torkel Lodberg) Organization: Dept. of Informatics, University of Oslo, Norway Lines: 30 Nntp-Posting-Host: kvart.ifi.uio.no Originator: torkell@kvart.ifi.uio.no In a message, Matti Joutkoski writes: >JR-Comm is truely lazy, and hard load to the Amiga. It have problems >with 38400. Well you can't really blame Jr-Comm. As a matter of fact, it has a very quick Zmodem transfer protocol that should stick with much faster transfer speeds than 38400 baud. The real problem is the Amiga system and the serial.device. Receiving fast wouldn't have been a problem on the Amiga if it had been a single-tasking system. But when multi- tasking, there isn't much CPU left for transfers and any transfer at speeds above 31500 baud *will* give you problems. The only exception is for programs that completely take over the machine and jump straight on the hardware (which isn't a nice thing to do on the Amiga). The buffer will actually overflow, which means that you will loose incoming data. Another very annoying thing is that bringing another screen to front during a transfer at 38400 baud may give the same result even if CTS/RTS has been set. One reason for this may be that CTS/RTS is handled by software (read: serial.device) and not hardware like on other systems. I guess the Amiga would have been better suited for fast transfers if CTS/RTS would had been properly handled by hardware. 38400 baud works pretty well on the A3000 (due to the more powerful CPU) but it is still irritating that data may disappear during a transfer. Especially this makes it very unsafe to use a protocol like Ymodem-G. T.Lodberg InterNet: torkell@ifi.uio.no Fido: 2:502/110 UUCP: ...!cbmvax!cbmehq!cbmnor!lodberg!torkel