/* this provides functionality somewhat similar to mmap() but using
read(). It gives sliding window access to a file. mmap() is not
used because of the possibility of another program (such as a
mailer) truncating the file thus giving us a SIGBUS */
/* this provides functionality somewhat similar to mmap() but using
read(). It gives sliding window access to a file. mmap() is not
used because of the possibility of another program (such as a
mailer) truncating the file thus giving us a SIGBUS */