exxos's Atari, Amiga & retro forum

I've done at least a couple of SD card solution reviews so far, and now I have the Dragon 32 running sensibly, I thought it was time I reviewed the CoCoSDC. I'd given it a bit of a bad review in my head, but it seemed that was mostly the fault of the Dragon, and now that's repaired, I can be somewhat more objective about the whole thing.

The CoCoSDC came in a nice 3d printed case, and looks very nice:


And once plugged in, you can see the DW4/SDC and DOS extensions once booted:


The command SDIR will show you the contents of the SD card, and in my case I have the SDCX file browser disk image in the root of the card. This software is much like SofaRun on the MSX Mapper. To mount the browser disk image, which is in VDK format, you type the command SDRIVE 1,"SDCX". This mounts the image SDCX.VDK as disk 1 and it can then be browsed using the DIR command just like DOS.


Alternatively, if like I do, you know the name of the software, you can simply type RUN' SDCX" and the file browser will start with a nice colourful splash screen:


Leading to the browser itself:


You can now browse the contents of the SD card and simply select the image using the arrow keys, be it a disk or ROM and hit enter to run it. It is smart enough to determine just what you're running.

Multiple drives can be configured with the SDRIVE command, but it should be remembered that when used with a Dragon the drive mappings start at 1, not 0. I have attached the manual, but be aware it mostly covers the use on a Tandy CoCo which given the name, it's not a surprise that it's compatible with both with some minor dip switch/jumper settings on the cart the only major physical difference.

One other nice feature is that if you have a game requiring multiple disks, so long as you follow the file naming convention described in the manual, you can simply switch disks by pressing the button on the end of the cartridge next to the SD card slot.

For the Dragon, most disk commands differ from the CoCo in that you prefix them with an S. So the CoCo command to mount an image would be Drive, but for the Dragon it's SDRIVE etc.

There are some very close parallels to the MSX Mapper in terms of operation, however where the MSX Mapper can autoboot the SofaRun software, and the CoCoSDC manual suggests this is possible, I haven't yet been able to make SDCX autoboot, so have to run the commands each and every time after a reboot.

Nonetheless, once running it is on a par with the MSX Mapper and almost as good as FinalGrom for the TI99/4a (Personally the best overall IMHO).

One nice addition is the configurator, executed by the RUN "CONFIG" option once SDCX.VDK is mounted:


Which allows you to choose some useful options, like disabling the splash screen, and remembering the last directory, plus you have the option to change the colours away from the lovely Dragon green!!!

Overall, it's very similar to the MSX Mapper, in that you do need to do some set up and configuration to get going. However once you get there, it's a useful add on for your Dragon or CoCo.

One last thing. The Dragon and CoCo are based off the same reference design for a 6809 based computer, however whilst some software will run, not all is compatible, so your mileage may vary when downloading disk images.

The Dragon tends to use the VDK format, and the CoCo uses DSK. Just be aware of this so if something fails to load and run, it may just be because it's for the other platform. In fact there are separate versions of SDCX for both platforms.

Hope this is helpful for anybody looking for an SD card solution for the Dragon/CoCo.

Wasn't there two competing incompatible disk formats for Dragon32?

DragonDOS and Delta.

Games were released in one, or both formats.

Does this handle both? Or are Dragon32 disk images format agnostic?

alexh wrote: 09 Sep 2022 11:11 Wasn't there two competing incompatible disk formats for Dragon32?

DragonDOS and Delta.

Games were released in one, or both formats.

Does this handle both? Or are Dragon32 disk images format agnostic?

It's a bit confusing, as there is no specific manual for the Dragon, just the CoCo, so it's a bit confusing. If you want more detail on the formats, it's all detailed in the manual in chapter 6.

It supports DSK, VDK, JVC and SDF image formats, and in fact on the Dragon I have loaded DSK images fine that contain basic programs, so you can mount them, it's just the contents that may not work if specifically for the CoCo.

I have also mounted images that do work but have a Tandy splash screen.

I am all very new to the Dragon too, and the CoCoSDC does also have a ROM facility. There are 4 banks, the first contains the extended DOS ROM, the 3 others are free for you to flash as desired.

Ok, so I have now been able to get the SDCX.VDK to automount at boot, which is a step forwards.

It was as simple as adding the line:

1=SDCX.VDK

to the file STARTUP.CFG in the root of the SD card.

It seems that the EXP command that you could use to auto run SDCX doesn't work on the Dragon, but I'll take this for now as it means all I have to do is type RUN"SDCX" once booted and I'm there :)