How to run "drive A required" software from a Gotek "drive B"?

Jonathan · 23:45, 02 January 25

I'm very happy with my new external Gotek! But I've noticed that some software only runs from drive A.

For instance, I found two versions of Dizzy among my 3" discs - when run from the Gotek one gave the "drive A disc missing" error and the other didn't.

This made me wonder whether there is anywhere online:
* where modified versions are available for download, and/or
* that just states whether the disc image can be run from drive B.

I'm aware of the potential for opening up the computer for an ABBA switch, but am exploring the non-surgical options first!

Thanks.

St-BeidE(DE/GB) · 00:51, 03 January 25

Quote from: Jonathan on 23:45, 02 January 25Thanks.

I'm unaware, how you connected your Drive B to the CPC. There is a simple method, to switch your gotek to drive A. However, your 3"drive is hidden/disfunctional
as long as B is A.
Connect pin 11 and 12 of the floppy cable to do so.
https://www.cpcwiki.eu/index.php?title=Guide_on_how_to_connect_a_3.5%22_drive_to_a_CPC6128/664&mobileaction=toggle_view_desktop
(Making floppy primary drive).

Maybe even better explained here:
http://www.cpcmania.com/Docs/Floppy/Floppy.htm

Stefan

eto · 02:34, 03 January 25

Quote from: Jonathan on 23:45, 02 January 25* where modified versions are available for download, and/or

check out cpcrulez.fr and cpc-power.com

Most cracked versions (especially the more recent ones) will run fine from B.

Jonathan · 13:21, 03 January 25

I downloaded Lemmings and Guild of Thieves from CPC Power (another amazing website) and both required drive A. I don't think drive B was mentioned but it might have been lost in translation! I'll check out CPC Rulez next.

I'll look into the hardware option too - thanks.

eto · 15:01, 03 January 25

Quote from: Jonathan on 13:21, 03 January 25I downloaded Lemmings and Guild of Thieves from CPC Power (another amazing website) and both required drive A. I don't think drive B was mentioned but it might have been lost in translation! I'll check out CPC Rulez next.

Make sure to select the cracked versions. The website design makes it easy to miss the right icon/tab if you are not used to it.

ZorrO · 20:32, 03 January 25

Check out this and next picture:
https://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5#Two_heads_.28OPTIONAL.29

Jonathan · 21:28, 03 January 25

The first comment on the video below also suggests shorting pins 11 and 12, but one reply says it didn't work and another that it worked on AMSDOS but not CP/M. I'd be happy to try a switch though wouldn't be capable of making one!

I'll look more carefully at the CPC Power download options - thanks.

St-BeidE(DE/GB) · 22:53, 03 January 25

Quote from: Jonathan on 21:28, 03 January 25The first comment on the video below also suggests shorting pins 11 and 12, but one reply says it didn't work and another that it worked on AMSDOS but not CP/M. I'd be happy to try a switch though wouldn't be capable of making...

Well, I really can't say, if it works on CP/M.
It works however on my system, with a Gotek in
all the other cases.
On the other hand, why would you need that switch
with CP/M? You can use your System Disk on (real) drive A, and program disks on gotek ?

Stefan

Jonathan · 00:53, 04 January 25

I can confirm that the cracked version of Lemmings on CPC Power and the version on CPC Rules both worked from the Gotek on drive B. I should probably register on those websites and leave a note to that effect.

No such luck with Guild of Thieves.

Is there any relatively easy way of changing a disc image to run from drive B?

As far as CP/M is concerned, I was just reporting what I read. Maybe he meant he couldn't run |CPM from a disc image in the Gotek (though if the Gotek is A: when the CPC is switched on I don't know why not).

ZorrO · 07:22, 04 January 25

But why all the trouble? On the tape to drive B, you short-circuit two wires and computer sees both drives as A. Then all that's needed is for internal drive not to have a floppy disk for external drive to react and work as A. You can make such a switch in 5 minutes, and modifying thousands of programs to work from drive B would take years.

Jonathan · 09:43, 04 January 25

Why all the trouble? I was balancing what I knew about the software vs hardware approaches to this.

Until the posts above I hadn't realised the switch was possible without soldering the board. Until your most recent post I hadn't realised it was a five-minute job (and I wasn't so sure that it was guaranteed to work). The comparison for me personally isn't with as many as 1000 software modifications, but it still sounds like the balance is in favour of the hardware approach :-)

I'm not handy, but what parts should I buy if I were to have a go at it? Thanks.

ZorrO · 12:41, 04 January 25

Study table of signals on this page.
https://www.cpcwiki.eu/index.php/DIY:Floppy_Drives
Don't confuse the numbers because each computer model has them differently. There are also 34-pin and 26-pin ribbons. It is important which side the pin in a different color is on. You need to short-circuit the Drive Select 1 signal to Ground. You can do this without soldering by connecting an additional plug (like for a drive) to ribbon, just to put there switch in it, as in picture below. This second switch is very useful for selecting head in 3.5" drives but unnecessary in Gotek. The picture shows a 26-pin ribbon and you probably have 34. Think about it and you will manage.

andycadley · 12:56, 04 January 25

Quote from: Jonathan on 00:53, 04 January 25Is there any relatively easy way of changing a disc image to run from drive B?

The answer to that is no, you basically have to reverse engineer all the code and change everywhere that loading happens. Which can vary from very trivial, to incredibly complex. There is no one-size-fits-all approach.

And that's why people favour hardware ABBA switch type approaches, that just change which drive the hardware thinks is which.

Jonathan · 13:34, 04 January 25

This sounds promising. Could you recommend specific parts from an online shop? (Like CPC Farnell, appropriately enough!)

In the meantime I'll look out for cracked versions of games.

simulant · 16:41, 05 January 25

Hi Jonathan, glad you are enjoying the new external drive. Here's a post I also made about getting some sort of software solution to this: https://www.cpcwiki.eu/forum/software-related/hex-editing-games-and-software-to-use-drive-b/

Jonathan · 20:57, 05 January 25

Thanks. I think the neatest solution would be an AB switch on the rear of the Gotek case. Second best would be the ribbon cable switch suggested here.

(AB rather than ABBA by the sounds of it, but I don't think I'd ever need to use the internal drive as drive B.)

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How to run "drive A required" software from a Gotek "drive B"?