Turbo MMC

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Modern solid-state storage solutions for the BBC Micro Model B, B+, and Master.

OldSkoolCoder reviewing BBC Micro MMC

Available to purchase from ctorwy31's eBay store here.

Running software

Once the MMC system is active you can run the games menu by entering;

*DBOOT 0 (or *DB.0 should work)

There is no guarantee that all the games will work on all machines. Alien Dropout, for instance, does not work properly on a BBC Master. Disk number 2 contains a small number of games or demonstration programs. You can run these using any of the following:


*DIN 2 followed by CHAIN “MENU”

Accessing individual disks and files

What follows now is a brief guide to some of the basics. The MMC filing systems is effectively a DFS environment rather than ADFS. There are four drives available numbered 0 to 3. The MMC card will contain up to 511 disks which are inserted into the currently selected drive using the *DIN command. It may help to think of the MMC card as being a box containing (typically) several hundred 80-track single sided disks. Just like the 5.25" drives of old, you need to ‘insert’ disks in order to use them. Of course, this is done with a software command rather than fumbling about in a box of diskettes. For example, disk 4 has been loaded with a few utilities and you can access them like this:


*DIN 300


What this does is select drive 0, insert disk 300 and then show the filenames on that disc. Many * commands can be abbreviated, but we will use the full commands here for clarity. Three of the files shown are sideways ROM images. These are BUTIL, AXR, and MXR.

Very briefly, BUTIL is a general purpose BASIC ‘toolkit’ ROM. The AXR is the Assembler Extension ROM and the MXR is a Maths ROM. The full manuals for these products are included on the CD. The AXR and MXR are perhaps a bit specialised but we believe that you will find B-Utility quite handy. The three ROM images and their respective manuals remain the copyright of © IFEL.

RFS is a machine code program to format programs for the ROM filing system. See the RFS.pdf document for a full explanation of how to use it.

RLOAD is a small program which can be used to load sideways ROM images into any chosen socket, The syntax is:

*RLOAD <image name> <ROM socket in hex> (Q)

The Q (Quick) parameter is optional. When Q is included then loading will be much faster but the main memory will become corrupted because it is used as a buffer. Leave off the Q if you don’t want this to happen. For instance


will attempt to load the file BUTIL into socket number 11 (hex B) and will use main memory as a buffer to speed the process up.

Returning to the basics of the MMC, you could try the following;


*DIN 312

You will almost certainly get an error message saying that the disk is not formatted. To remedy this just enter:

*DFORM 312

*DIN 312

*CAT will now show a newly formatted disk but with no files on it. Remember that this is disk number 312 in drive 2.

As with DFS, you can give disks titles. For instance:


You will see this title when you catalogue the disk (*. is an abbreviation for *CAT)

The currently selected drive is 2 and contains a blank, newly formatted disk 312. Drive 0 still contains disk number 300. One of the files on drive 0 is RLOAD. To copy this to disk 312 in drive 2 you could use:


0 is the source drive, 2 the destination drive and RLOAD is the file to copy

*COPY 0 2 *.*

copies all files on drive 0 to drive 2.

A useful hint, nothing specifically to do with the MMC card, is that typing:

?&FE4E=127 (or use *FX 151 78 127)

then pressing Break is almost equivalent to turning the machine off and then back on again. It is a handy way of performing a fairly drastic reset and you will lose the contents of main memory. In the Master with MOS 3.50 it will even clear the sideways RAM contents too.


A special file may exist on the disk called !BOOT. Often this file contains various lines, each of which is a command of some sort. Such files can usually be dropped into some kind of text editor (eg Wordwise) or you can even use *TYPE !BOOT to see what the file contains. It is possible to execute the commands in the !BOOT file by entering:


Sometimes the !BOOT file needs to be *RUN in which case:


can be used.

Certain MMC cards may have a suitable !BOOT file placed on disk 0. If your machine is configured to power up with the MMC system as the default filing system, then switching on the computer with the SHIFT key held down should cause the !BOOT file to be run automatically. Often this will bring up a menu of options within a second or two.

Some further details on the various commands can be found in the DUTILS.pdf file.