Themes p.33 Computing on the Run [author Stanley J. Wszola] Incorporating new design concepts, innovative hardware, and easy-to-use software, portable computers are proof that you can take it with you. This month's theme articles and reviews explore the issues that affect the portable marketplace, the advances in technology, and some of the latest models. p.34 How to Choose a Portable [author Stanley J. Wszola] You're sure you want one, but which one? With at least 50 models to choose from, deciding on a portable is no easy matter. This article and the accompanying computer comparison table will help you make an informed choice. p.51 High-IQ Modems [author Stephen Durham] The more intelligent the modem, the more it can disappear into the background of your computer system and provide unattended communications capability p.66 Developing a Truly Portable Visicalc [author William T. Johnson] Hewlett-Packard's adaptation of Visicorp's popular electronic-spreadsheet program for its HP-7S portable computer doesn't sacrifice the program's compatibility with other Visicalc products. p.80 The Gavilan - A Full-Function Portable Computer [author F. John Zepecki] The machine's designer details…