Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!jarthur!nrossi From: nrossi@jarthur.Claremont.EDU (Nick Rossi) Newsgroups: comp.sys.cbm Subject: Re: Interfacing a Commodore 64 with a VAX/VMS Message-ID: <11611@jarthur.Claremont.EDU> Date: 9 Apr 91 01:09:29 GMT References: <1991Apr7.012003.423@vax1.mankato.msus.edu> <2HV_JWD@cs.widener.edu> Organization: Harvey Mudd College, Claremont, CA 91711 Lines: 17 In respponse to the Zmodem question with a RAM expander... The NMI caused by the DMA process in a RAM expander DOES interfere with incoming data. This can be proven by capturing incoming data directly to a REU - every 255 bytes or so, a bit of garbage will occur, which is caused by the DMA. I can see it working with flow control, and it would certainly be faster than with a disk drive. But I don't think it would be any faster than the protocols already available on the 64, which is why I and others have said that it isn't worth the effort to write Zmodem for the 64. ------------------------------ +---------------------------------+ Nick Rossi, '93 | SONY | ------------------------------ | | Harvey Mudd College | Because caucasians are just | (ooo HELL is a place on earth) | too damn tall. | ------------------------------ +---------------------------------+