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From: die@cpoint.UUCP (David I. Emery)
Newsgroups: comp.arch,alt.next
Subject: Re: The NeXT Problem
Summary: Does the next optical media wear out ?
Keywords: Curie point, local heating
Message-ID: <1359@cpoint.UUCP>
Date: 19 Oct 88 09:33:00 GMT
References: <26435@ucbvax.BERKELEY.EDU> <7774@gryphon.CTS.COM> <9287@bigtex.cactus.org>
Reply-To: die@cpoint.UUCP (David I. Emery)
Organization: Clearpoint Research Corp., Hopkinton Mass.
Lines: 26


	Most previously announced erasable optical media (such as Tandy's)
allow only a limited number of write erase cycles before the media
deteriorates enough to signficantly effect error rates.  I beleive the
Tandy product was qouted as only supporting around 10 write erase cycles.

	Does the NeXT/(Cannon?) media have any limit on the number of write
erase cycles allowed ?   It appears to be erased by thermal techniques
(heating above the Curie point),  how many heating/cooling cycles can
the material undergo without changes in crystal structure that effect
data SNR (annealing effects perhaps) ?

	Does this mean that the NeXT optical floppies have the possibility of
wearing out in spots ?  Doe the file system do anything to compensate.

	Can the disks be erased by modest high temperatures (such as leaving
one in a hot car (160-180 F) or bright sun ?

	David I. Emery   Clearpoint Research Corp. 
	99 South Street, Hopkinton Ma. 01748  1-508-435-2000
	{decvax, cybvax0, mirror}!frog!cpoint!die 

-- 
	David I. Emery   Clearpoint Research Corp. 
	99 South Street, Hopkinton Ma. 01748  1-508-435-2000
	{decvax, cybvax0, mirror}!frog!cpoint!die