The lowly disk drive is getting the kind of respect usually reserved for places like Thomas Jefferson's Monticello and Hewlett-Packard's renowned garage. Last month, the San Jose City Council designated a little building in downtown San Jose, Calif., as a historical landmark,the site where data storage was born. About 50 years ago, IBM inventor Reynold B. Johnson created the first hard-disk drive,the result of research conducted in a laboratory on 99 Notre Dame Avenue in San Jose. Since then, the hard-disk drive has gone from storing 5 MB of data in a six-foot-high 305 RAMAC to storing 1 GB of data in a PDA that fits in the palm of your hand. Businesses now depend on thousands of hard-disk drives to store and retrieve millions of bytes of data. San Jose's City Council is hailing 99 Notre Dame Avenue as a site symbolic of "the emerging development of Silicon Valley in the 20th century."