ncm@zembu.com (Nathan Myers) writes:
> I don't know if you get the point of the fixed-size comment field.
> The idea was that a comment could be poked into an existing COPY
> image, after it was written.
Yes, I did get the point ...
> A variable-size comment field in an
> already-written image might leave no space to poke in anything. A
> variable-size comment field with a required minimum size would
> satisfy both needs, at some cost in complexity.
This strikes me as a perfect argument for a variable-size field.
If you want to leave N bytes for a future poked-in comment, you do that.
If you don't, then not. Leaving 128 bytes (or any other frozen-by-the-
file-format number) is guaranteed to satisfy nobody.
regards, tom lane