Computers with 48-bit words include CDC 1604

CDC 1604

The CDC 1604 was a 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation. The 1604 is known as the first commercially successful transistorized computer. Legend has it that the 1604 designation was chosen by adding CDC's first street address to...

 and BESM-6.

The IBM AS/400, in its CISC

Complex instruction set computer

A complex instruction set computer , is a computer where single instructions can execute several low-level operations and/or are capable of multi-step operations or addressing modes within single instructions...

 variants, is a 48-bit addressing system. The address size used in logical block addressing

Logical block addressing

Logical block addressing is a common scheme used for specifying the location of blocks of data stored on computer storage devices, generally secondary storage systems such as hard disks....

 was increased to 48 bits with the introduction of ATA-6.

The minimal implementation of the x86-64

X86-64

x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...

 architecture provides 48-bit addressing encoded into 64 bits; future versions of the architecture can expand this without breaking properly written applications.

Images

In digital images, 48 bits per pixel, or 16 bits per each color channel (red, green and blue), is used for accurate processing. Such images do not look much better than 24-bit images, but the existence of more shades between colors (65,536 as opposed to 256) means that more operations can be performed on the image without risk of noticeable banding

Colour banding

Colour banding is a problem of inaccurate colour presentation in computer graphics. While in 24 bit colour modes, 8 bits per channel should be enough to render images in the full visible spectrum, in some cases there is a risk of producing abrupt changes between shades of the same colour...

 or posterization

Posterization

Posterization of an image entails conversion of a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another. This was originally done with photographic processes to create posters...

.