So you'Ve got your eye on an amazingly powerful new PC that's so cheap you're contemplating splurging on a DVD-ROM drive instead of a boring old CD-ROM. Well, hang on a second. There's a new option to confuse, er, excite the PC marketplace: You'll soon be able to record on DVDs, erasing and rewriting them like huge, removable hard drives.

Unfortunately, the proposed standards for rewritable DVD are themselves being erased and rewritten all the time. Things were simple enough with CD-ROM and DVD-ROM (the DVD read-only format that can also read CD-ROM discs), but then DVD-R (write-once DVD) arrived; are you ready for DVD-RAM, DVD-RW and DVD+RW?

What's going on here? We were supposed to have one DVD standard. The read-only version of DVD works for computer storage and video playback because many warring manufacturers buried their format hatchets and agreed on a common technology that they all could share. But the market has fragmented into a minefield of confusing new acronyms, and once again a format war is simmering along the DVD DMZ.

The write-once format called DVD-R has been available since late 1997 and stores 4.7 gigabytes of data per side, but it's designed for the professional market and has cost as much as $17,000 per drive. Newer versions like Pioneer's recently released DVR-S201, however, run a "mere" $5,400 each; another price drop like that might turn this into a home-use product.

The three rewritable formats have more immediate appeal to consumers. Of the bunch, DVD-RAM has been out the longest, since the middle of 1998. These drives sell for $500 to $800 each, hold 2.6 gigs per side and usually require the disc to be in a caddy (like Jurassic-age CD-ROM drives). The discs also can't be read by normal DVD-ROM drives, except for one Panasonic model (Toshiba, Hitachi, and Panasonic support this standard). Blank discs cost $25 single-sided, $40 for double-sided versions.

The second rewritable format, DVD+RW (pronounced "DVD plus RW") is scheduled to launch this fall, with drives costing around $700. Discs will store 3 gigs on each side, won't require a special cartridge and will be readable in any DVD drive; blank single-sided discs should sell for $35 to $50 each. The format also has the backing of such major industry leaders as Sony, Philips, Hewlett-Packard, Ricoh and Yamaha.

Finally, the DVD-R specification is, in turn, spawning a third rewritable format, DVD-RW (not pronounced "DVD minus RW"), which will hold a full 4.7 gigs per side while remaining readable by standard DVD drives. Its main backer is Pioneer, a company that was working on rewritable discs back in the pre-DVD laserdisc days. With its professional-grade capacity, however, expect a professional price.

Don't place total faith in that fall arrival schedule; all of these formats have suffered delays due to the movie industry's insistence on a bullet-proof copy protection scheme that will prevent you from giving flawless DVD copies of the latest hit DVD movies to all your friends.

Do any of these manufacturers remember the struggles over VHS vs. Betamax in the '80s? Instead of agreeing on the best technology, companies staged a marketing war instead, in which millions of innocent consumers caught in the cross-fire paid a terrible price -- $300 to replace a perfectly good Betamax VCR. We suggest you practice your own civil defense and not buy any of these "standards" until these knuckleheads get their act together, or we'll all end up rewriting history.