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Path: utzoo!syntron!orcisi!michael
From: michael@orcisi.UUCP
Newsgroups: comp.periphs,comp.unix.wizards
Subject: Re: Filesystem/archive formats for WORM optical disks
Message-ID: <614@orcisi.UUCP>
Date: Mon, 17-Aug-87 09:23:10 EDT
Article-I.D.: orcisi.614
Posted: Mon Aug 17 09:23:10 1987
Date-Received: Tue, 18-Aug-87 01:38:50 EDT
References: <1775@kontron.UUCP> <212@casemo.UUCP> <516@nitrex.UUCP>
Organization: Optical Recording Corporation, Toronto, Ontario
Lines: 27
Xref: syntron comp.periphs:461 comp.unix.wizards:3406

> >  ... [deleted for brevity]
> 
> I have notes of a conversation with (either) Don Wilde or Mike Konshak of
> Optotech, Inc. at NCC in July 1985.  One of the two developed an efficient
> scheme for bitmap updating on optical media so that files could be updated
> efficiently.
> 
> Optotech is in Colorado Springs, 303-570-7500.

Optotech uses a special construct called a "post field" in their
recording format that can direct a READ command to read an alternate
block of data rather than the immediately following the current block
(the latter being the usual case for optical media).  This scheme helps
reduce the "burn rate" at which optical media is consumed as far as
file updates go.  There are special commands for writing (once) the post
field of a block and for reading it.

One of the better models for optical media is "magtape with random read
access".


Michael Herman
Optical Recording Corporation
141 John Street, Toronto, Ontario, Canada  M5V 2E4

UUCP:  { cbosgd!utcs ihnp4!utzoo seismo!mnetor }!syntron!orcisi!michael
ALSO:  mwherman@watcgl.waterloo.edu