This is often deliberately misquoted with "abstraction" substituted for "indirection". This is often deliberately mis-quoted with "abstraction layer" substituted for "level of indirection". OPC allow indirection, chunking and relative indirection. For "unbounded" indirection we require a "hardware" change in our machine model. Rather than using indirection, pixel values directly represent Luminance. TEX limited indirection to 64 levels to avoid possible looping. As with the Luminance mode indirection is disabled and pixel values directly represent a color. The conceptual view provides a level of indirection between internal and external. Such a "bounded indirection" is a laborious, tedious affair. SVC implements an indirection, or "virtualization", layer in a Fibre Channel storage area network (SAN). Hartmanis (1971) specifies an instruction set with indirection, citing lecture notes of Cook (1970). Higher-level examples of indirection are the design patterns of the proxy and the proxy server. Looking up something in the map requires inefficient double indirection. The theory contended that addressing is a wasteful and non-valuable level of indirection. The use of poetic indirection is a key feature of "fu".