GoSDC SD Card Interface In-Depth Review - Part 2

In Part 1, we took delivery of the GoSDC and installed it into the Model B. In Part 2, we're going to check the GoSDC is installed properly, and prepare the SD card.


Checking the GoSDC is Installed

The instructions provided by John tell you to start up the BBC (see pic 1 below), and run the command: *SDCINFO

See pic 2 for the results from *SDCINFO

Great, so it appears the hardware installation was successful. The Beeb is detecting the GoSDC in ROM slot 15, with the 'free ROM slot' (the one that's in the GoSDC) appears in slot 13. Incidentally, the 'X' area shown here is a kind of reserved area from which you can read but not write (I think John had a plan to possibly use this to provide some bundled disk and tape images). We can also run the command *SDCCONFIG with no parameters to display the current ROM configuration as seen by GoSDC. Note: this does not detect other ROMs that you may have in your BBC.

Areas are exactly what they seem. Distinct locations on the SD card, numbered from 1 to 8. The default is '1' and that's all we'll be using for this review.

Preparing the SD Card

OK, now we've confirmed the GoSDC is installed, onto the preparation of the SD/SDHC or MMC card. For the purposes of this review, we're using the small 16 MB MMC card that John kindly provides bundled with the GoSDC. Unlike some other SD card interfaces, with GoSDC the SD card preparation process is more complicated than just copying the disk image files across to the card in Windows or via your Mac Finder window.

The first thing to do is to power down the Beeb and insert the MMC card into the GoSDC (see pic 1 below). Once installed, power up the Beeb again. Notice that the earlier message on startup that read: "GoSDC : No flash card inserted" has now disappeared (see pic 2). Run *SDCINFO again. Note that a new area is now shown called '1' with the total size in bytes (16 MB in our case).

Now type *SDCAREA

You're presented with the details of the default first area on the card, which is area '1'. Note that it also tells us "Selected area is not formatted". I then run


This formats the area on the SD card with a proprietary file system that is only readable by GoSDC and its accompanying tools. The format task is almost instant, and should report back "Formatting area... done, Verifying format... done, Please hard-reset your machine now". I duly hit Ctrl-Break, and re-run


We now have area 1 formatted and ready to go (see pic 4 above).


Adding Content to the SD Card

Now we need to load up some disk, tape or hard disk images onto the card. This is where I hit my first hurdle. To get disk images onto the card you can do so in one of two ways. If you have an actual BBC floppy drive, you can run some GoSDC commands that extract the contents off the disk and create a disk image on the card (a very handy way to backup your own programs and commercial floppies). The second way, and the way I did it due to lack of a BBC floppy drive, is to use the 'GoSDCio' utility. GoSDCio is a command-line executable that runs on Windows, Mac, or Linux.

John's website instructions provide a great means of getting thousands of disk and tape images to get you up and running quickly. A set of batch files are provided with the GoSDC software that connect to the old Stairway to Hell FTP site and download all the freely available disk and tape images. Further batch files can be run to group these into areas if you want to, e.g. an area for DFS disks and an area for tapes. I decided not to make separate areas, as I'm only installing a handful of DFS disk images for the time being. The batch files also generate a single text file called script.disk and script.tape that contain all the GoSDCio commands.

The easiest way to run GoSDCio.exe is from a command-line or a Terminal window). The following command runs GoSDCio and instructs it to execute all lines from a text file:

gosdcio -dG script.disk

The -d argument is followed by the drive letter of the SD card. Even though the SD card can no longer be read by the operating system, it *can* be read by GoSDCio. If you want to put a single disk image onto the SD card, run this:

gosdcio -dG -c "ADD DFS DISC N Alligata.Blagger disks\Alligata\Blagger\Blagger.ssd"            

And to list the contents of the SD card, run this (that's a lowercase 'L' at the end):

gosdcio -dG -c "" -l

To add an image to a different area, you can simple add the -a<n> argument to GoSDCio to put the disk image into area 'n' (from 1 to 8).

As per John's instructions, step one is to identify the device ID that the SD card reader is using. This is done by clicking on About this Mac->System Report->USB and finding the 'BSD Name' of the USB Mass Storage Device for the SD card drive. In my case it was "/dev/disk1".

I then opened a Terminal window, navigated to the location where I had downloaded the GoSDC software, and ran:

chmod755 ./gosdcio
sudo ./gosdcio -d/dev/disk1 -c "" -l

entered in my superuser password and it worked. This command simply lists the contents of the SD card. From that point the rest was quite painless. To get the script.disk file running successfully from the Mac I had to replace all backslashes (as used by MS-DOS/Windows for directory separators) into forward slashes (as used by Unix). The easiest way to do this (if you ever need to) is to run this from Unix:

tr '\' '/' <script.disk >script2.disk

which creates a new file called script2.disk with the translated values.


One key thing not to be overlooked here is that despite some problems I faced, GoSDC provides the Acorn BBC with a true disk interface. To the BBC it never knows it's dealing with anything apart from a real DFS/ADFS, a real disk drive, and real floppy disks, so compatibility should be near enough 100%. Not all SD interfaces can claim that.


Now we have an MMC card with some disk images installed, it's time to see if it works in Part 3.




This page was last updated on 5th February 2015.