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Floppy Disk

Is it true that the 800XL can't run certain software programs for the 800?

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Yes and no….

 

There are a few difference between the OS B (or OS A) in Atari 400/800 and the XL/XE OS (most of them have the rev. 2 XL/XE OS)

 

There is a solution in the form of a translation disk, which it makes possible to run almost any OS B title on your XL/XE computer...

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As already stated, most software of this type can be run using a Translator disk, though that leaves out cartridge software that doesn't support booting from floppy.

 

An alternative is third party XL OS's that offer OS B compatibility.

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As already stated, most software of this type can be run using a Translator disk, though that leaves out cartridge software that doesn't support booting from floppy.

 

An alternative is third party XL OS's that offer OS B compatibility.

 

I think there is a program that acts as a translator that can handle cartridges. I wish I remembered more. I'll have to dig a little.

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Would it be possible to flash OS B to one of the 'OS ROM' slots of an 'Ultimate1MB' and select that as your running OS? Would that obviate the need for a translator?

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Would it be possible to flash OS B to one of the 'OS ROM' slots of an 'Ultimate1MB' and select that as your running OS? Would that obviate the need for a translator?

Well, almost. There are a couple of differences in hardware you cannot translate by the Os itself. Port B of PIA has to be an output for the XL machines, but it is an input on Os B. Leaving the pins of the MMU "floating" because the port is configured as input "usually works" because TTL logic usually reads open inputs as "high-level", so this would configure the XL machine as "Os present, Basic absent", which is typically what you want.

 

The second problem is the reset key. It will always cold start the XL machine with an Os B rom inserted, no matter what. This is because reset works differently. On the old series, reset was rather a soft-reset initiated by an Antic NMI, on the new machines it is a true hardware reset where coldstart and warmstart are distinguished by a couple of "magic RAM values" that survive the reset (and, unfortunately, sometimes even a short power-off).

 

This being said, the first difference is worked around by the translator disk, though the second is unfortuntely "unfixable" both by the translator and an Os B rom.

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Well, almost. There are a couple of differences in hardware you cannot translate by the Os itself. Port B of PIA has to be an output for the XL machines, but it is an input on Os B. Leaving the pins of the MMU "floating" because the port is configured as input "usually works" because TTL logic usually reads open inputs as "high-level", so this would configure the XL machine as "Os present, Basic absent", which is typically what you want.

 

The second problem is the reset key. It will always cold start the XL machine with an Os B rom inserted, no matter what. This is because reset works differently. On the old series, reset was rather a soft-reset initiated by an Antic NMI, on the new machines it is a true hardware reset where coldstart and warmstart are distinguished by a couple of "magic RAM values" that survive the reset (and, unfortunately, sometimes even a short power-off).

 

This being said, the first difference is worked around by the translator disk, though the second is unfortuntely "unfixable" both by the translator and an Os B rom.

Fascinating stuff!!! I always wondered what the seemingly magic 'Translator' disk did - and why a short power off could give flaky results sometimes. I guess you would have to take in to account the missing 2 joystick ports as well!

 

Damnit... This thread just makes me wish all the more that I had an 800 - with an Incognito of course!!!

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Damnit... This thread just makes me wish all the more that I had an 800 - with an Incognito of course!!!

 

800 with incognito I think is the ultimate 8-bit Atari. This discussion though does get me thinking, does the Incognito provide a true reset option to the 800 when it is in XL/XE mode? Maybe it doesn't matter to software in that direction?

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Many 800-only games have been modified by the Atari community to run on XL machines unmodified. Most of the fixed versions can easily be found in this forum.

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There were certain cartridges that only worked on the 800 and certain cartridges that worked only on the xl/xe had to do with cartridge pins signaled by ras instead of phi2... as outlined here in this fix. http://atariage.com/forums/topic/212137-how-to-make-the-myide-ii-work-on-a-atari-800-with-incognito/?p=2750855

You could always put a toggle switch in or gate to switch it either way on both machines and make all of them work...

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Port B of PIA has to be an output for the XL machines, but it is an input on Os B. Leaving the pins of the MMU "floating" because the port is configured as input "usually works" because TTL logic usually reads open inputs as "high-level", so this would configure the XL machine as "Os present, Basic absent", which is typically what you want.

 

Actually, it's guaranteed that setting port B to input will switch an XL/XE machine to OS on, BASIC off, self-test off. On hardware reset the PIA switches all ports to input, and there are pull-ups on those pins. It has to work, or else the machine wouldn't boot. Furthermore, while the unused pins are left floating, in tests that I've done on 800XL and 130XEs, those pins are actually eventually drift to read as low, not high.

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