Path: utzoo!attcan!uunet!husc6!cmcl2!rutgers!mcnc!rti!tachyon!sch
From: sch@tachyon.UUCP (Steve Holzworth)
Newsgroups: comp.sys.mac
Subject: Re: NeXT press release (very long but interesting)
Summary: Magneto-Optical disk is REAL.
Message-ID: <192@tachyon.UUCP>
Date: 14 Oct 88 15:54:58 GMT
References: <5423@juniper.uucp> <72886@sun.uucp>
Organization: William G. Daniel & Associates, Cary, N.C.
Lines: 40

In article <72886@sun.uucp>, swilson%thetone@Sun.COM (Scott Wilson) writes:
> Hmm, this looks suspicious to me.  Note that the the terms "vast
> storage capacities", "removability", and "reliability" are used to
> describe laser technology while "full read/write/erase" capabilites
> are associated with Winchester (magnetic) technology.  Does this mean
> that it is nothing more than CD-ROM and an old-fashioned hard disk
> packaged together?  
	. . .
> 
> 
> --
> Scott Wilson		arpa: swilson@sun.com
> Sun Microsystems	uucp: ...!sun!swilson
> Mt. View, CA

Nope, it's a real thing.  A company called Alphatronix in Research Triangle
Park, N.C. has a similar (same?) product.  Note that it is a combination
of technologies.  Paraphrasing from an article in "Digital Review":

The technology takes advantage of the fact that the media can be recorded
magnetically and read by a laser.  The disk is heated to 150 degrees C, which
enables a magnetic bias field to "flip" bits in the disk.  The media itself is
normally magnetic north up.  If a bias field is applied to it, the bit will
be flipped down.  (the high temperature makes this possible).  When polarized
light is projected onto the bits, an up bit twists it one way and a down bit
twists it another.  Based on the new orientation of the beam, the data is
interpreted as a one or zero.  Note that the bit flipping only happens at
high temperature, so when a cartridge is removed, it is basically involatile,
even under intense magnetic fields.  Average seek time is 83ms.

End paraphrasing.  I know someone who has seen the Aplhatronix version work.
They also dropped a heavy-duty magnet on the disk cartridge and moved it
around, with no ill effect on the data.  The core drive is supplied by Sony.
I assume the NeXT version is similar.  The Alphatronics system is designed
to work on the Q-bus or Unibus.  They can be reached at (919)544-0001.

No, I don't work for any of the above parties, etc. etc.

						Steve Holzworth
						rti!tachyon!sch