HP Computers, a seller of personal computers worldwide, today said it's throwing its weight behind a new class of miniaturized laptops targeted primarily to students, a growing market already populated with products like Intel Corp.'s Classmate PC and OLPC's XO laptop.

HP's teeny laptop venture comes in the form of a new computer called a "Mini-Note" that weighs less than 3 pounds, with a screen that measures 8.9 inches diagonally. The machines start at less than $500 for a Linux-based model. Prices go up for Windows Vista models with faster processors.

HP executives say their new machines, which go on sale later this month, are an important piece of the company's effort to build market share in schools, where machines have to be smaller and cheaper without losing too many functions.

The company also expects adults to gravitate to the idea of buying two laptops -- a lightweight one just for Web browsing on the go and a full-power machine for the home or office. But industry executives acknowledge that the market is untested and that no one knows what the demand will be once the machines are deployed widely.

HP executives say the only major feature its Mini-Note lacks is an optical drive for using DVDs and CD-ROMs, which can be bought separately. But they say many schools request that the drives be left out to prevent students from playing unauthorized games.

HP also says it plans to provide free, online professional development courses designed to help teachers engage students' interest and improve their achievement through the use of technology.