Were any programs released this way?

[nikoniko]

I vaguely recall that at least one C64 program I owned had an Apple II version on the flip side, but I wasn't aware of any that had multiple systems on a single side.

Multiple system disk

US Patent number: 4562495
Filing date: Jul 2, 1984
Issue date: Dec 31, 1985
Inventors: Charles R. Bond, Ronald M. Sturtevant-Stuart
Assignee: Verbatim Corporation

Abstract
A multiple system data storage disk adapted for use with more than one type of computer. The disk is specially formatted to include software for each computer. The disk includes four discrete recognition headers, one for each target computer, placed at locations on the disk where each computer expects to being its data loading operation. Each header further includes software directing the computer to step out to a discrete group of data tracks located elsewhere on the disk. Each data track group contains an identical program, written in each target computer's language. The disk is suited to video games for multiple computers. An alternative embodiment of the disk includes a header or headers containing a magnetic signature for copy protection. A disk can be produced with twenty-four such headers, one for each type of computer on the market, which can be mass produced to provide low-cost copy protection for all machines.

[Blacklord]

Amiga Format & ST Format both released multiple format disks for both machines that could be read in either. This is the only one I know of.

cheers,

Lance

[airship]

I've got Sargon Chess with Atari 400/800 on one side and the C64 on the other, but that's the only one I've got that's a flippy, I think.

I know that you COULD partially format a 1541 or 1571 disk with different sectors for different machines (Apple, Atari, CBM, etc.), but I don't know how you'd come up with a loader that would reside on the same disk and run on all machines.

Do the Apple and Atari use different start locations than CBM's track 18 for their directories?

[airship]

Here's what's on Wikipedia:

"Apple DOS 3.2 was released in 1979 to reflect major changes in computer booting methods that were built into the successor of the Apple II, the Apple II Plus. Instead of the original Integer BASIC, the newer Applesoft BASIC was written into the ROM of the II+. Also, the new ROM had an updated computer reset function, dubbed Autostart, which could boot a disk automatically when the II+ was powered up..."

"Apple DOS 3.3 was released in 1980. DOS 3.3 improved various functions of DOS 3.2, while also allowing for large gains in available floppy disk storage; the newer P5A/P6A PROMs in the disk controller could read and write data at a higher density, so that instead of 13 sectors, 16 sectors of data could be stored per disk track, increasing the capacity to 140 KB per disk side, with about 130KB available for user programs..."

"DOS 3.1 disks used 13 sectors of data per disk track, each sector being 256 bytes in size. It used 35 tracks per disk side, and could access only one side of the floppy disk, unless the user flipped the disk over. This gave the user a total storage capacity of 113.75 KB per disk side, of which about 10 KB were used to store DOS itself and the disk directory, leaving about 100KB for user programs."

But nothing on where The 'autoboot' code resides on the disk.

[airship]

I found this COMPUTE article about a loader that lets an Apple load a PET program.... from cassette!

http://www.atarimagazines.com/compute/issue8/3048_1_THE_APPLE_GAZETTE.php

[Guest]

It sounds like Verbatim Corp. was trying to cover a base.
They were hoping or heard that the software developers and manufacturers were going to make a disk drive that would load programs from a multi-formatted disk.
If so, they would have the patent on the disk format.

Dan...

[nikoniko]

I found this COMPUTE article about a loader that lets an Apple load a PET program.... from cassette!

Wow. That has to be one of the niftiest Apple II utilities ever written! Too bad AtariMagazines.com doesn't archive program listings.