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David Banks edited this page Dec 17, 2022 · 13 revisions

Introduction

MMFS is a modern SD Card solution for 8-bit Acorn Computers.

MMFS is one of several ROMs that allow modern SD Cards to be used on a Beeb with minimal external hardware (others include the original SuperMMC, Steve Picton's TurboMMC and Duikkie's SmartSPI).

MMFS was written by Martin Mather in 2012, but seems to have been forgotten about until it was rediscovered in 2015.

MMFSv1 and MMFSv2

MMFS is provided in two versions which differ in the way that floppy disc images are stored on the SD card.

In MMFSv1 there are many floppy disc images bundled into a single MMB file on an SD Card.

In MMFSv2 floppy disc image files are stored directly on a FAT32 formatted SD Card without any MMB file.

MMFSv2 is not intended as a replacement for MMFSv1, but rather supports a different mode of operation.

In both versions of MMFS the individual disc images may be loaded into virtual drives for access from the BBC Micro using commands like *DIN explained in the Command Reference.

Both versions will be developed in parallel for the forseable future.

While it is possible to have the MMFSv1 and MMFSv2 ROMs installed at the same time, it rarely makes sense to do this because they access disk images in different ways. So a disk image that is visible to MMFSv1 will not be visible to MMFSv2 (and visa versa). In addition, on a Model B you would need to use a ROM manager to make sure only one of them is active at a time, otherwise the default value of PAGE will be too high for most games. On a Master it's easier, because of better support in MOS 3.2 for multiple file systems.

Features

MMFS has the following features:

  • it's derived from DFS 2.x rather than DFS 0.9
  • it supports MMC, SD and SDHC cards
  • it supports FAT32 (upto 8GB) as well as FAT16
  • it supports large (>64KB) files
  • it contains the TUBEHOST 2.30 code for second processors
  • the Master and Beeb/Electron SWRAM versions result in PAGE at &E00
  • it preserves the current drive on BREAK
  • it is under active development

User Documentation

See Command Reference
See DFS to MMFS Transfer

Configurations

MMFS supports multiple machines:

  • Model B
  • Model B+
  • Master 128 (and Master Compact)
  • Electron

MMFS supports both ROM and Sideways RAM:

  • ROM (PAGE=&1900 on Model B and Electron, PAGE=&E00 on Master 128)
  • Sideways RAM (PAGE=&E00 on Model B and Electron)

MMFS supports multiple SD card interface boards:

  • Original SD card interface
  • TurboMMC card interface

MMFS supports multiple ways of connecting to the machine:

  • Normal User Port (&FE60)
  • Additional User Port on the Master 128 modem connector (&FE80)
  • Additional User Port on the Master 128 econet connector (&FEA0)
  • Electron User Port (&FCB0)
  • Electron Printer Port (&FC71/&FC72)
  • Memory mapped SPI interface (&FE18)

There is a different MMFS ROM image for each of these hardware configurations, and the MMFS release .zip file includes all of them in a hierarchical folder structure. One of the challenges for someone getting started with MMFS is to select the image that most appropriate to their machine and the type of interface adapter. For more details on selecting the right ROM image, please refer to the Release Structure page.

Support

If you have any issues with MMFS, then please report them in the development thread on Stardot:

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