Message from discussion Zmodem PD 65c02 Source

Path: gmdzi!unido!mcsun!uunet!elroy.jpl.nasa.gov!usc!jarthur!nntp-server.caltech.edu!toddpw
From: tod...@nntp-server.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: Zmodem PD 65c02 Source
Message-ID: <1991Jul31.042742.18008@nntp-server.caltech.edu>
Date: 31 Jul 91 04:27:42 GMT
References: <1991Jul30.115721.5784@crash.cts.com>
Organization: California Institute of Technology, Pasadena
Lines: 22

ta...@pro-odyssey.cts.com (Joe Quilici) writes:

>In-Reply-To: message from shrin...@Apple.COM

>I remember someone stating that Z-modem is impossible to do on an Apple //,
>mainly because it is a streaming protocol and the Apple can't directly
>write the incoming data to the HD; instead having to pause to write.  Does
>your code automatically pause the send, load the data or save the necessary
>data, and continue sending?

At the risk of putting words in Andy's mouth, his code has to do one of two
things:

	tell the other end to pause sending
	just write to the disk and let the garbled packet be retransmitted

ANY micro using a disk controller that causes interrupt blackouts faces the
same choice, and in no way does it prevent one from implementing Zmodem. It
does put take a bite out of the maximum transfer rate though.

Todd Whitesel
toddpw @ tybalt.caltech.edu