No. As I understand it this is a leftover feature from old times when certain programs needed to have a certain byte order specified to read tiffs.
Kind of. It's actually a leftover from the days when writing 16-bit data needed to be done in a way that corresponded to the "byte order" of a given processor.
Some computer processors--most notably, those from Intel--are "little-endian" processors. That means, when the processor stores a two-byte number n memory, it stores it *backward*--that is, little-end first. The number "1000" is seen by an Intel processor as "0010." The number "1492" is "9214" to an Intel
processor, and the number "12345678" is "34127856.". Every pair of digits is swapped with the pair to its right.
Intel does this for historical reasons; their first 16-bit processor did this because it was easier to keep certain architectural features from the early 8080 that came before it. As a result, even the Pentium 4 processor has certain quirks that trace back to the ancient 8080.
Other processors, like those from Motorola and other processor companies, don't swap the digits. "1492" is stored as "1492," not "9214." These processors are
"big-endian"--the big part of the nummber comes first, as it does in normal human-readable writing.
The TIFF standard allows numbers to be written in little-endian format so that programmers who write software for Intel processors do not have to go and manually swap the numbers around when they read the TIFF into memory. Adobe calls the byte-order format "Mac" and "PC," but they should be called "Intel
(little-endian)" and "everything else." The so-called "Mac" format means nothing more than "Record the information on disk in a normal order, without swapping all the pairs of numbers around."
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