Reflecting the growing popularity of slim, lightweight computers, Toshiba Corp. announced Tuesday that it will start selling two new personal computer models, including the world's slimmest and lightest B5-size subnotebook computer, which will go on sale Friday.

The new models from the DynaBook and Libretto series will hit the market just before the July 25 release of the Japanese version of Windows 98, Microsoft Corp.'s new operating system.

Hoping the new Windows 98 OS will stimulate sales, Toshiba offers upgrade services for those who purchase the new models. The new DynaBook SS 3010 and 3000 are the world's slimmest and lightest B5-size models, measuring 19.8 mm and weighing 1.19 kg with 64 megabytes of main memory.

The DynaBook SS 3010 model incorporates a 266-MHz Pentium processor with MMX technology, the fastest processor in any computer of its class, and is equipped with 4.3 gigabytes of storage.

The DynaBook SS 3000 has a 233-MHz processor and a 2.1-gigabyte hard disk.

The DynaBook SS 6000, an A4-size notebook PC, is 23.5 mm in height and weighs 1.79 kg. Either Windows 95 or Windows 98 can be preinstalled in the model, according to Toshiba.