10 YEARS AGO — MARCH 11, 1999 Handheld PC keeps on-the-go executives in touch: The HP 660LX palmtop computer from Hewlett-Packard is the first handheld PC to come with a 56k modem and 32-Mbyte RAM, double the memory of most palmtops. Priced at about $1,000, the device gives users fast access to e-mail and the Internet, and enough memory to store files, applications, and images. The 256-color 660LX uses Windows CE operating system and has a one-year warranty.

30 YEARS AGO — MARCH 8, 1979 Service hangar slides and folds around DC-9: A triangular aluminum- clad hangar that features movable work docks suspended from a monorail has been developed by Ozark Air Lines. The 24,000-ft2 structure, designed by R&D Constructors, has a cantilevered roof that eliminates almost all support posts, freeing floor space for work areas. Work docks and air-filtration and painting equipment make the hangar a self-supporting work center. The sliding-roof and folding/ sliding doors open to let aircraft be towed in.

50 YEARS AGO — MARCH 5, 1959 Tiny timer tends missile parts: A miniaturized elapsed-time indicator contains a 1-W synchronous motor that runs on aircraft accessory current (115 V, 400 cycles), a jeweled geartrain with 180 million:1 ratio, and an internal reset mechanism. It will record up to 1,000 hr to give needed information on aircraft and missilecomponent reliability. The 1.2-oz, 1¼-in.-long timer withstands 10-g vibration at 500 cps, 15-g shock, and works in any temperature from –40 to 165°F. Produced by Elgin Micronics Div., Elgin National Watch Co., Elgin, Ill., the timer can be mass produced and is used in current weapons.