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The BBC Master 512

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Method 1 | Method 2 | Method 3 | Method 4

DOS-Plus and GEM System Software

The Master 512 was supplied with the DOS-Plus and GEM systems on four (5¼") floppy disks. These were labelled:

1 – DOS-Plus Boot Disk
2 – GEM Applications
3 – GEM Data
4 – Miscellaneous

See below for details of their format and contents.

Creating the System Disks

If you have acquired a Master 512 without the system disks (or if your disks have been lost or corrupted without adequate back-ups) then you will need to create fresh copies. This is not quite straightforward because the disks are in Acorn's proprietory formats. In particular, the boot disk is in 640kb DOS format – a kind of hybrid between DOS and ADFS because the 512 has to use some native BBC Computer facilities to get going. You cannot start the Master 512 from a standard PC boot disk.

All the software necessary to create the system disks is available from this web-site. Today it is possible to connect the BBC directly to the Internet, but it needs extra hardware. If you do not have this you will need to download the system-disk data onto another computer. (I'll assume it is a PC.) The disks can be built from this using the PC along with the Master 512 itself. Some of the files can also be used as disk images to run the Master 512 in an emulator.

There are several methods of building the disks, depending on what facilities you have.

Obviously, if you are using a PC for downloading, you must have a means of transferring the system-disk data from it to your BBC Micro. This means you must have:


Compatible sized disk drives – you may have a PC with a 5¼" disk drive, or else you may have set up your BBC Computer to use 3½" disks and have a PC that can use them too. (See here, for instance, for some advice on using 3½" disks with a BBC Computer.)


A direct data link, which can be done with a lead connecting the BBC's RS423 port to an RS232 (COM) port on the PC. (This does mean you will have to have such a port on the PC. It used to be the case that all PCs were fitted with one or two COM ports, but some more modern machines have replaced them all with USB. It is not straightforward to connect a BBC computer to USB.)

With one or both of these, some methods you can use are:

1. Writing the disks on a PC

If you have compatible sized drives, then you may well be able to write the system disks directly on your PC from disk images.

Many PCs can be persuaded by suitable software to use BBC format disks, and if this is the case for you then the system disks can be created quite easily – details and resources are given here.

If it works, this is by far the simplest method of creating the disks.

2. Transferring all the data through the serial port

If you do not have compatible drives but do have an RS232 serial port on your PC, then you can transfer the data via a cable between the two computers. It is not too difficult to make up a cable that will link one of the PC's COM ports to the RS423 port on the BBC (provided you can get the parts). There is also software that can transfer data through such a link.

Making the 512 system disks this way is slow and a little bit fiddly, but it can be done. Click here for details and resources.

3. Using disks after initial manual program entry

Perhaps you cannot coax your PC into writing to 640kb Acorn format disks, despite having compatible sized disk drives, and maybe you cannot use a serial link either.

In that case it is still possible to write a program for the BBC Micro which will enable it to read from a PC (DOS) disk. This way you can create a basic boot disk, and using it you can start up the 512.

You will have to type the initial program into the BBC manually, but after that you can transfer all the necessary data using DOS disks. Apart from this typing in, the process is fairly straightforward, and of course it only needs to be done once. All resources and details can be found here.

4. Using both disks and a serial link

It may be that you cannot get your PC to write the disk images. However, if you have compatible sized drives and you also have a serial link between the two machines, then you can compromise between Methods 2 and 3 above and speed up the process considerably. This entails transferring a single BBC Basic program along the link and from this you can set up a minimal boot disk. Then you can boot up the 512 and transfer the rest of the data between the two computers on fully PC-compatible disks.

Once again details are provided on this site, so click here.

In Detail – How to Create the Disks

Click on one of the following for details of how to create the system disks using one of the methods just outlined.

         Method 1: Writing the disks on a PC
    Method 2: Transferring all the data through the serial ports
    Method 3: Using disks after initial manual program entry
    Method 4: Using both disks and a serial link

Note: To use the Master 512 it must have either two 80-track double-sided floppy disk drives, or one such drive and a hard disk. It must also be equipped with the ADFS filing system. In addition you need a supply of Double Density (not High Density) disks.

Since these are essential to use the machine at all, it is assumed in all of these methods that you have this much.

Software for an Emulated Master 512

You can run an emulated version of the Master 512 in a program such as BeebEm. That includes Version 1.2 of the boot disk, but if you wish to use the updated version of DOS-Plus (Version 2.1) and the full set of supplied system software, download the Method 1 Package. Some notes about using the images with an emulator are given here.

Contents of the System Disks

      Disk 1   

The DOS-Plus boot disk. It is in Acorn 640kb Bootable DOS format, and to start the 512 you have to use this disk (or the software from it transferred to a hard disk). It contains the DOS-Plus operating system files and all the system utilities.

There are three versions of this disk – the original with DOS-Plus Version 1.2, a slightly revised one (Version 1.2a) and the upgraded Version 2.1

  Disk 2   "GEM Applications". This contains the GEM system, including the Desktop and the Output utility, and also the two principal user programs: GEM Write and GEM Paint. It is in Acorn 800kb DOS format.
  Disk 3   "GEM Data". This contains some introduction and tutorial documents for GEM Write (in GEM Write format) and some sample GEM Paint images, as well as a number of GEM printer fonts for various printers. It is again in Acorn 800kb DOS format.
  Disk 4  

Miscellaneous items – another Acorn 800kb DOS format disk. This contains a number of device driver files for use with GEM. These are: two screen drivers (an alternative monochrome driver and a colour screen driver), several printer drivers and a plotter driver. Again for GEM, there are further printer fonts, in addition to those on Disk 3, plus a set of updated screen fonts. Also there is the GEM Setup program, which does not work! (Click here for instructions on how to use any of these resources with GEM.)

There are a couple of other items on this disk besides the GEM resources. These are:

         A demonstration program to show that the Master 512 doesn't have to be silent. BBC sound facilities could be used by any programmer writing solely for this machine.
    A Z80 and CP/M emulator for the 512. This is offered with no support whatsoever, and I have no idea whether it works properly or not.

Method 1 | Method 2 | Method 3 | Method 4

About the 512 | Software | Index