izumi@violet.berkeley.edu (Izumi Ohzawa) (01/08/89)
I am just curious. Is there any spec on the maximum G-force during *operation* of the erasable optical drive ? Is it much better than magnetic hard disks? Is it good enough to mount in a car and to compute as you drive? Izumi Ohzawa
matt@frisbee.UUCP (Matt Taylor) (01/11/89)
> I am just curious. Is there any spec on the maximum G-force > during *operation* of the erasable optical drive ? > Is it much better than magnetic hard disks? > Is it good enough to mount in a car and to compute as you drive? > Izumi Ohzawa Most optical drives, magneto-optic or otherwise, are "effectively" immune to shock or vibration. The key word here is "effectively". While you can certainly generate tracking errors (although some drives do track better than others), you can't have a head crash like you can in the magnetic world. Canon's magneto-optic drive should handle shock and vibration just as well as any other optical drive (assuming they did their homework, which they probably did). Case in point, our WORM drive has shown very few problems handling abnormal movement during reads or writes. One of the things I like to do during demos is to start a big copy or directory listing, then start vigorously shaking the drive as hard as I can or drop the drive from about 6 inches off the table. The expression on people's faces is priceless when everything keeps on working without any errors or loss of data. Try that with a magnetic drive! :-) (I don't recommend doing this with the NeXT box though. :-) Since you can't have a true head crash with an optical drive, the only real error is a tracking error. But, so what. Just reseek to the track and continue on. However, because most magneto-optic drives use much smaller tracking voltages in the head, they are generally more susceptible to shock or vibration. This means that tracking errors will be somewhat easier to induce. If Canon did the hardware correctly and the drive can detect errors quick enough, it really becomes a software issue. Our drive is immune to rough treatment because our software knows how to notice and handle spontaneous drive errors. It's expected. If the software group at NeXT (or whoever wrote the device driver) kept the same philosophy, then there shouldn't be any problem with their drive either. ----------------------------------- Matt Taylor @ Maximum Storage, Inc. Colorado Springs, CO. 719-531-6888 {cbosgd,handel,hao,hplabs}!hp-lsd!frisbee!matt