Re: Do Write Once TM's Halt?

Torben Ægidius Mogensen wrote:
....
TM's don't have infinite tapes, they have unbounded tapes. The
important difference is that the tape at all times has finite support,
i.e., that it is blank outside a finite range (the size of which may
change during execution).
....

I think infinite input tapes might lead to an interesting model of
modern computer services.

The traditional Turing machine models a single batch computation, in
which the TM gets all the input, and either computes some function of
the entire input, or fails to do so going into a loop.

Many computer programs now operate as services, required to produce some
results based on the input so far, but then continue to process more
input. At least conceptually, they go on running that way for ever, and
always expect to find more input. This is the case, for example, for
on-line machine learning algorithms, and for web servers.

However, whether that is a useful model of computation, and its
implications if it is useful, are separate questions from write-once and
read-only behavior.

Patricia
.