Why sync three times

[Tom Truscott]

On UNIX V7, it was possible to type 'sync' followed by interrupt (e.g. DEL)
rather than newline and not be able to tell the difference.
This is still possible if control characters (e.g. interrupt)
are not made visible via 'ctlecho' or some such.
Typing 'sync' several times
increases the probability that the command gets done.
(But anyone who has had an important 'cp' finish early due to a noisy
phone line will appreciate the merits of 'ctlecho'.)

Also, the fact that the 'sync' system call is not synchronous
makes people nervous, and with good reason.
Is this bug fixed in any version of UNIX?
	Tom Truscott