Initially, the ability of personal computers to perform signal processing or multivariate analysis was severely limited by small memory address space and lack of scientific language support. Recently, however, this situation has changed, with large memory sizes common and with the availability of mainframe languages such as FORTRAN-77 to support complex and double-precision expressions. Today, personal computers can be applied to data collection, multivariate analysis, pattern classification, simulation of signal processing hardware, and other engineering applications. We discuss the conversion of mainframe data analysis software for personal computers, and the use of high-resolution personal computer graphics for data displays. The process is illustrated with the conversion of part of the IEEE signal processing library and of the ARTHUR81 multivariate analysis routines to run on a personal computer. Timing and accuracy results are given for two personal computers--the TI Professional and the IBM PC AT. The use of a personal computer to validate data, obtain measurement statistics, perform classification and cluster analysis, and perform modern spectral analysis is illustrated with run information and typical output displays.