Can UNIX pipe connections be compiled?

[Guy Harris]

>But only to THINK of a pipe as a file, under unix there never IS a file.

Well, under *some* versions of UNIX (V7, S3, and I think it's still true
in S5, prior to S5R4), a pipe is sort-of implemented as a file, complete
with an inode *and* a list of N direct blocks pointed to by that inode;
those blocks really do end up containing the data in the file, although
if you're not unlucky, the data will be consumed before the block ever
has to be written to disk.