A RAQ is a 1U server originally sold by a company named CObalt, later bought by Sun Microsystems.
RAQ's come in several varieties. The early models, eg RAQ, RAQ2, were based on MIPS processors. Later versions, eg. the RAQ3's, 4's wer based on AMD K6-2 processors. The last few versions , eg XTR, 550, were iirc based on Pentium III's.
All of these ran on either a Proprietary OS (for the MIPS machines) or a modified version of Linux (RAQ3 and later). They had from one to 3 NIC connections, serial console ports and space for 256M-1(2?)GB RAM and one or 2 internal hard drives and a front LCD monitor panel. What made RAQ's popular was a proprietary administartion interface that made them simple to manage.
There were also special models designed specifically for caching and NAS applications. An interesting variation was the Cobalt Qube which was a small 8" blue cube that contained a complete workgroup server. The model 2 was MIPS based, the Model 3 x86.
Many companies, especially ISP's use/d RAQ's as an effective and inexpensive web and DNS servers. They are still sold as dedicated servers by web hosting companies.
A search for Cobalt RAQ or just RAQ will yield lots of links. Used RAQ's can usually be purchased readily on eBay.