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N3000 NeXT Optical Drive |  | ||||||
| The NeXT Optical Disk rotates at a brisk 3000 revolutions per minute. Like a compact disk it has a layer of reflective aluminum backing, on top of which is a magneto-optical substrate. The substrate is comprised of the crystals that actually hold the information. True to digital tradition, information on an optical disk exists as either of two-values, "o" or "1". The value is determined by the magnetic orientation of the crystals. Unlike a floppy or Winchester disk, an optical disk cannot be altered by a magnetic field alone. At normal temperatures, the orientation of its crystals remains locked. Read and write operations are performed by a single laser. Before wnew data is written, an "erase" process takes place. An electromagnetic device activates, preparing to orient susceptible crystals to the "o" position. The laser then focuses on the substrate heating it to its Curie point. (If your physics is rusty, that's the temperature at which the cystals in the substrate "unlock," and allow themselves to be reoriented in the presence of the magnetic field.) In this manner,a ll portions of the disk to be written are erased. Next comes the writing procedure. The magnetic field is reversed so that it will reorient those sections of the substrate that reach the Curie poing to the "1" position. Every spot to be set to the "1" value is the heated by the focused laser. Upon completeion of the writing procedure, a second pass is made to verify accuracy. In reading data, the magnetic field is turned off. A low-level laser is aimed at the disk, travelling through the substrate and reflecting off the aluminum backing. Enter the Kerr effect - in which the alighnment of the crystals in the substrate alters the polarization of the reflected beam. The beam travels through a polarizing filter to a photodector, and the intensity of the beam determines whether "o" or "1" was read at that particular spot on the optical disk. Simple. The NeXT optical disk provides mass storage that is portable, reliable and cost-effective. It is shown on the left. | |||||||
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| 1989.10 1990.10 1992.? |
Sometime that year NeXT also introduced additional options that included 330MB and 660MB SCSI Hard Disk system drives. The basic system consisted of the NeXT Computer 8MB RAM, MegaPixel Display, NeXT Keyboard, NeXT Mouse, 40MB Accellerator Drive all for the low price (to educational customers of $4,995) 68040 Systems were introduced and 68040 upgrade Motherboards were made available for the Cubes. The NeXTDimension was also announced but did not start shipping tocustomers until 1991. At some point NeXT decides to drop Optical Drive support in Cubes - and this is seen in the last public upgrade for the cubes which is the 33Mhz 68040 - Turbo cube which does not support the NeXT Optical Drive. | ||||||