ABSTRACT
This chapter discusses generic Unix kernel modifications designed to improve the system clock accuracy, ultimately to the order of nanoseconds when a sufficiently accurate reference clock is available. Relative to a previous version described in [1], it provides about ten times smaller time and frequency errors and a thousand times better time resolution. The modifications include a set of subroutines to be incorporated in the Unix kernels of various architectures, including Digital (RISC, Alpha), Hewlett Packard (Alpha and PA2), Sun Microsystems (SPARC, UltraSPARC), and Intel (x386, Pentium). The new design has been implemented for test in Tru64 5.1 and SunOS 4.1.3, and is a standard feature of current FreeBSD and an add-on feature of current Linux.
