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From: blarson@skat.usc.edu (Bob Larson)
Newsgroups: comp.periphs,comp.sys.dec
Subject: Re: Helical-Scan Query
Message-ID: <9807@oberon.USC.EDU>
Date: 14 Jun 88 05:54:07 GMT
References: <2648@usceast.UUCP>
Sender: news@oberon.USC.EDU
Reply-To: blarson@skat.usc.edu (Bob Larson)
Organization: USC AIS, Los Angeles
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In article <2648@usceast.UUCP> baldwin@usceast.UUCP (Chuck Baldwin) writes:
>     The following reply, from David Lesher:
>>there is NO way to
>>verify (read after write) on a vcr [besides stopping the tape,
>>going back to the beginning, reading and comparing, etc]

While this is true of your ordinary VCR, I've heard it is not true
of at least some computer tape drives that use VCR tapes.
There is no techincal reason on a VHS style tape that prevents 
extra tape from beeing pulled out of the cartrage to run it over
a second rotaing tape head.  The 4 mm (DAT) cartrage seems based
on the same type of technology.  (I've never examined an 8 mm tape
closely.)  This obviously wouldn't be cheap, but with prices
more than an order of magnatude higher than home VCRs, it seems
beleivable.

[I've been looking at three vendors with alternative tape solutions
for Primes, based on VHS, 8mm, and 4mm(DAT).  (Arn't standards lovely?
Tapes should be easily available, but nobody can read tapes from the
other brands.)]

>>the ones I have seen record each file several times in hope
>>that one is perfect. 

Early ones (and probably the current cheepos) did do this,
but hopefully there has been some advance in the last 5 years.

-- 
Bob Larson	Arpa: Blarson@Ecla.Usc.Edu	blarson@skat.usc.edu
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