IDE-CF adapter blues

 
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Using Compact Flash cards as harddisks on the Amiga has been possible for some years now, and when compared to more traditional type of harddisks, it is a very good alternative indeed. Not only are CF cards generally a bit faster, they are also physically smaller in size as well - which makes it a little easier to place them in wedge type Amigas. Another thing is that CF cards also is very light on the power usage.
But there are of course certain problems with this solution as well. One thing is that not all Compact Flash cards out there will actually work on the Amiga (I have been most successful with SanDisk & Transcend cards myself). Another thing is that there are some software issues too, where IDEfix and the standard HDToolBox in AmigaOS 3.1 and lower needs to be patched by using this and this. Other than that, there's also the actual required IDE-CF adapters as well, which you can read more about below.

Most of the 40 pin IDE-CF adapters I have tried, have worked just fine as long as it has been the only thing connected to the IDE cable. Trying to connect another IDE device, whether it has been another CF adapter, harddisk, or CD-ROM, have always lead to either none or only one of the devices being recognized by the Amiga. For the most part, the type of adapters I have used, has been like adapter A in the picture below. Using them with another device attached to the same cable has never worked for me. Adapter B like types on the other hand, have mostly worked just fine with two devices.    

I have for some time been wondering about the reason behind this, and after inspecting them a bit closer, I belive I have figured it all out. Because other than the shape, orientation and connector colors of the adapters, there are also two other major differences as well:

1. Notice the exact wording for Master/Slave settings on adapter A, which reads: 1-2: MASTER/SLAVE, 2-3: SLAVE/MASTER. Then look at adapter B, which quite simply reads: ON: MASTER, OFF: SLAVE.
 
2. Take a look at the back side of both adapters, and you may notice that A has some extra solder pads, just like that an extra CF connector can be mounted there. B on the other hand, have no such extra pads on the back.



My theory is that board A (and similar types) originally is meant to be a dual CF card adapter that accepts two Compact Flash cards. The Master/Slave jumper is quite simply there for letting the user configure what slot is to be set as Master, which automatically makes the other one Slave. Even though there are no card slot on the back of the adapter, I belive that whatever IDE controller it is connected to, may somehow still recognize the missing slot as something extra present (like a drive with no disk inserted for example).
So if this adapter + CF card is connected together with a traditional IDE drive to the same cable, the system may then recognize this as either 2 Masters + 1 Slave, or 1 Master + 2 Slaves being present. With two adapter A types attached to the same cable, things gets even worse since the system may then belive there's 2 Masters + 2 Slaves connected. All of this really confuses the hell out of the IDE controller.

With type B like boards on the other hand, there are for the most part not any problems, since they are originally meant to be single card adapters only. And they do actually have proper Master/Slave settings as well.


Conclusion
If a single Compact Flash card + adapter is the only thing to be connected to the IDE cable, adapter A types should work just fine. But if another IDE device is to be attached to the same cable, I will recommend a type B like adapter to be used instead.

Please note the following:
1. Both adapters shown above uses 40 pin IDE connectors, the 44 pin ones have some other issues as well (see below).
2. Adapter B is usually sold with a PCI bracket, and it's originally intended to be mounted at the back of a PC.
3. For the most part I have only tried cheap adapters bought on Ebay, the ones sold by various Amiga dealers may not have the issues described on this page.




Dual IDE-CF adapters
Currently I'm using 40 pin dual CF adapters in both of my A1200 machines, where they are of the adapter A type with an extra CF socket. The main Amiga has a 2GB + 8GB Compact Flash card, and the other one has two 2GB cards. The adapter in each Amiga is connected to a IDE-Fix board. These setups have for the most part worked just fine with a patched IDEfix file. The only issue has been removing the Slave card, since this have required disabling Unit 1 in IDEfix Prefs first. Otherwise the Amiga would most often hang upon running IDEfix during boot.

Dual 44 pin adapters on the other hand, have always been a different story. No matter what I have done, I never had any success with using two CF cards with them. Either only one card would be recognized by the system, or none of them would. A possible reason can be that the internal IDE port of the A600 & A1200 isn't able to power both cards, but most likely it's because the adapters uses Cable Select instead of Master/Slave settings. I have noticed that some of the 44 pin adapters (both single and dual) lacks a proper M/S jumper, which leads me to belive that they only use CS instead.

Anyway, I would highly recommend that for any IDE device you want to buy, make sure that it actually has a Master/Slave jumper first.  If such a jumper is lacking, the device is most likely Cable Select only, which really isn't supported on the Amiga. You may still manage to get it working though, but it will in most cases be with only one device connected to the IDE cable.





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