DOS 3.2 issue solved (Now on 16 sector disks)

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Joined: Apr 23 2022 - 18:41
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DOS 3.2 issue solved (Now on 16 sector disks)

I decided to post a new thread on this subject rather than going to the bottom of my old post and adding to it.  I have attached 2 files that I made which are DOS 3.1 and DOS 3.2 system masters on 16 SECTOR DISKS. These images can be written with ADTPRO like you would write any other 5.25 disk. Both have been tested in my integer basic Rev0. Since they are integer basic disks they will NOT boot in a iie.




S.Elliott's picture
Last seen: 14 hours 48 min ago
Joined: Jun 23 2022 - 16:26
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Since they are integer basic

Since they are integer basic disks they will NOT boot in a iie.

Ooo!  Maybe they will boot in my Apple IIe!

Not today, but soon.

Back in 1988, I modified this Apple ROM Card to accept twice as much ROM by exploiting an spare (unused) D flip-flop in the 7474.

Notice a missing resistor at top right?  I removed it in order to convert one of the 2716 chip-select pins into a 2732 bank-select.  That enabled the card to hold twice as much ROM by using 4K chips instead of 2K chips. [Media style: preview]

Some of the 2732 EPROMS on this card have become corrupted by bit rot so they need to be reprorgammed to make it work again.

You've inspired a frivolous little project: since the card needs reprogramming in any event, why not rebuild it so that it has one bank of complete Integer ROMs, and my own stuff stashed in the other bank?  That would enable my to boot my Apple IIe natively in DOS 3.1...just for the satisfaction of doing it.

I want to recover my degraded EPROMs first, but this might be an interesting thing to attempt after that.


PS: Here's the rest of my bank-switching modification on the back of the card.  Also, it's an excuse to test another picture style in the Media Browser.  [Media style: teaser]

In summary, my modification preserves Apple's original ROM soft-switches and adds a third setting:

  • $C0x0 - Firmware ON, read card ROMs.  (original Apple switch)
  • $C0x1 - Firmware OFF, read motherboard memory.  (original apple switch)
  • $c0x2 - Firmware ON, read card ROMs, alternate bank.  (new switch added via solder modifications)


Sorry if this seems off-topic, but I promise my end-goal is stritchly on-topic: I want to properly boot your 16-sector DOS 3.1 & 3.2 disks on an Apple IIe

Last seen: 1 hour 34 sec ago
Joined: Jun 18 2010 - 13:54
Posts: 727
Disks themselves are not

Disks themselves are not Integer or Applesoft BASIC. The "HELLO" program on them can be either, and with a Language Card you can first load the non-resident motherboard BASIC into it.


If you're looking to have both BASICs selectable on your Apple II (or IIe for that matter) motherboard, you might want to take a look at ROMX.

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