Defining Disk Image Dump Standard

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed May 31 17:48:09 2000

I wrote:
> On some later Infocom titles for the Apple ][ family, they went to two
> disk sides, and in order to maximize the amount of data on the second
> size (and hence minimize flipping), they went to *one* sector per track.
> This does away with the "wasted space" of intersector gaps.

Sellam wrote:
> Interesting. I never came across any of those. It probably also had the
> added advantage of allowing for very quick reads.

They did denibblize it on-the-fly, which normal RWTS did not. In that
sense, since they sustained the equivalent of 1:1 interleave, it was
pretty good. However, there was no reason why the same performance (but
not density) couldn't be achieved with standard sectors. The Apple ///
SOS disk driver pioneered this, and IIRC Prodos did it as well.

> Do you know of any specific titles that used such formatting? I probably
> have a few of the originals and I'd like to check it out.

I'm not 100% certain, but it would be on later titles that used versions
5 and 6 of the Infocom virtual machine to support large game images.
So it was probably used on Beyond Zork, among others.
Received on Wed May 31 2000 - 17:48:09 BST