The Jargon File (version 4.4.7, 29 Dec 2003):

Slowlaris
 /slo'?lahr?is/, n.

    [Usenet; poss. from the variety of prosimian called a ?slow loris?. The
    variant ?Slowlartus? is also common, related to LART] Common hackish term
    for Solaris, Sun's System VR4 version of Unix that came out of the
    standardization wars of the early 1990s. So named because especially on
    older hardware, responsiveness was much less crisp than under the preceding
    SunOS. Early releases of Solaris (that is, Solaris 2, as some marketroids
    at Sun retroactively rechristened SunOS as Solaris 1) were quite buggy, and
    Sun was forced by customer demand to support SunOS for quite some time.
    Newer versions are acknowledged to be among the best commercial Unix
    variants in 1998, but still lose single-processor benchmarks to Sparc 
    Linux. Compare HP-SUX, sun-stools.