This website has many references to all aspects of computer/machine/hardware design to instruction and code implementation such as endian, signed/unsigned int, floating point representation etc. Nearly all architectures: IBM, Motorola, Intel, Mac; possible programming languaes: Assembly to c/c++ to unix shell script; Operating Systems from Admiral to WinXP. The website appears it hasn't been updated in a while, but there are many great resources here, if you need to look up something you have a great chance of finding it here http://www.osdata.com/index.htm
, just have a look at this website. Hope this helps!