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From: monty@sagpd1.UUCP (Monty Saine)
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech,comp.sys.amiga.hardware
Subject: Re: Re: CDTV Idea!
Keywords: CDTV,Networking,Cable
Message-ID: <846@sagpd1.UUCP>
Date: 9 Jul 90 20:23:33 GMT
References: <9350@life.ai.mit.edu> <5908@hub.ucsb.edu> <33522@ut-emx.UUCP>
Reply-To: monty@sagpd1.UUCP (Monty Saine)
Distribution: na
Organization: Scientific Atlanta, Government Products Div, San Diego, CA
Lines: 31

In article <33522@ut-emx.UUCP> lshaw@walt.cc.utexas.edu (logan shaw) writes:
--I can see only one problem with this:
--  I imagine you're going to want to download things in the form of packets
--  about the size of howevermuch data you can fit between frames.  Now,
--  to keep nasty errors out (much more important for software than for
--  video programs), I bet you'll have some type of checksum or some similar
--  way of checking for errors.  What do you do when you've found an error?
--  You can't send a packet back to the cable company telling them to retransmit
--  that last packet.  So I assume you'll have to just give a little error
--  message saying you couldn't record, cause there was a little error.
--  I supposed you could counteract this a little bit by sending tons and
--  tons of parity -- enough to detect and correct errors, but that may not
--  be enough, depending on how noisy cable TV is.
	
	How about multiple transfers of each packet? How many copies of
	each packet would be required to determine what data is incorrect?

	I am not up on error checking/recovery, but it seems that some
	form of redundant transfer protocol could be worked out. Also why
	does this all have to be done during the retrace period? There
	are many whole channels available on most cable networks. Why not
	have a dedicated channel for data a transfer service. Use the same pay
	for view technology that is in place. Give the users a menu of what 
	is available for download and set up an automatic receiver to accept
	the data when it is sent. Real time receipt would be nice, but this
	service should be cheaper than BBS and phone rates so a time lag might
	be acceptable.

	Just thoughts to mull over, no flames please. :)

	Monty Saie