Conference noted::ibmpc-95

    I just picked up a Toshiba 12X (aka XM5702 IDE) my first venture to
    IDE, really EIDE and a big jump from Sony 1X.  The Tosh cost $95.
    

I've held off on considering the latest round of faster CD-ROMs (hard to
call them "high end" when they go for under $100!) because of earlier
reports that they weren't designed for such speed.  What's the story today? 
Is there a risk?  Are the various models similar or do some sound more like
jet engines taking off?  Will they burn out under heavy use?

    The Toshiba, at least, is designed for 12x speeds.... But it does sound
    like a (quiet) jet when it spins up all the way. It idles at 4x, and
    spins up to 12 when accessed.
    
    BTW, the Toshiba is ATAPI, not IDE or EIDE. IT happens to connect on an
    EIDE bus, but the communication protocol is more like SCSI than IDE.
    
    Chris
    

Many of the new "fast" drives are rated at their fastest speed, towards the
outer edge of the CD.  What may be 12X out there (where few discs have data)
may be only 8X towards the center.  There's a new (to CD-ROMs, anyway,
laserdisc users will know it well) method called CAV where the disc spins at
a constant rate rather than slowing down towards the edge.  I see that
Plextor is advertising a drive which can reach 20X at the edge, with an
average of 16.5X.

				Steve

    Most, if not all, of the 12x drives are 12x for their entire capacity
    (i.e. they are still CLV disc drives). This rotates the media at about
    6400 rmp on the inner diameter, which is about the max for CD media.
    
    16x, 20x, and beyond (going to 32x or so) all use a combination of CLV
    and CAV techniques to get the speed up as they go toward the outer
    diameter of the disc.
    
    A 32x drive is still no more than a 12x drive at the I.D. of the disc.
    The advantages come from being able to seek faster, because you do not
    have to change the rotational speed of the disc as much, if at all.
    Access times in the sub-80 msec range will be possible in inexpensive
    drives...
    
    Chris