From: bill@bilver.uucp (Bill Vermillion)
Subject: Re: Interlocking two LD players
Organization: W. J. Vermillion - Winter Park, FL
Date: Tue, 1 Sep 1992 12:19:45 GMT

In article <1522@seqp4.sequoia.com> cantrell@seqp4.sequoia.com (Paul Cantrell) writes:

>In article <1992Aug24.034914.5923@wam.umd.edu>, dododge@wam.umd.edu (David O. Dodge) writes:

>> In article <1992Aug22.184820.14406@cis.ohio-state.edu> fontana@cis.ohio-state.edu (Mark Fontana) writes:

>> >I don't own a laserdisc player, but the following idea occurred to me:
>> >Although players exist that can play both sides of a disk, there
>> >don't seem to be any that allow you to chain multiple DISKS together
>> >using multiple LD players (provided you have the necessary $$$).  

>> If you're trying to get totally smooth transitions for movies it
>> can't be done easily.

>I've wondered why the two sided issue hasn't been addressed better. It
>seems to me that having two laser assemblies would solve the two sided
>problem. Only the head assembly would need to be duplicate. The rest of
>the electronics could be shared.

>The way I'd do it would be either two complete head assemblies (which
>has the problem of duplicating lots of mechanical positioning stuff)
>or have one assembly with a laser mounted on each side, one for side
>A, the other for side B. When the disk was loaded, first the table of
>contents on one side would be read, then the TOC for the other side.
>After side A has finished, the location to start playing side B is
>already known, and the delay would be the time it takes to reposition
>the head and search for the starting position. I would expect this to
>be worst case 2 seconds, and best case a small fraction of a second.


Good industrial players can seek in less than a second.  However the
problem is not positioning of the laser assembly.  It is slowing the
disk down from approximately 900 rpm going one way, to a full stop, and
then speeding it up to 1800 rpm the other direction.

To do this more rapidly would require more powerful motors, perhaps a
true braking system, and a definately stronger clamping system.

Then, all discs would have to be made for two types of players.  Ones
that rotated in one direction only, and ones that could play
'backwards'.     You'd never get dealers to stock dual stocks, and the
consuming public would be very confused.

To make sure people don't start coming back with 'bad' disks, you
really need to change the disk in a way to make it unique to that
player.  Perhaps a square center hole or something.


>My 3070 takes what, 10 seconds to switch sides? I find it annoying enough
>I'd pay an extra $100 for a clean side switch. A multi-disc player would
>be nice, and again I'd probably pay $100-$200 for this capability. No way
>would I pay 2x the cost to play 2 disks, 3x to play 3 disks, etc...

Listen to your 3070 as it switches sides, and I suspect you'll hear a
lot of time just ramping down the speed, stopping, reversing rotation,
and getting up to speed again.                    


-- 
Bill Vermillion - bill@bilver.oau.org  bill.vermillion@oau.org
                - bill@bilver.uucp 
                - ..!{peora|ge-dab|tous|tarpit}!bilver!bill

From: davea@hpscit.sc.hp.com (Dave Angelini)
Date: Thu, 27 Aug 1992 13:57:30 GMT
Subject: FOR SALE BETA TAPES
Organization: Hewlett-Packard, Santa Clara, CA