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Creating the System Disks – Method 2

Method 2: Transferring all the data through the serial port

This is your only method if you do not have compatible disk drives – quite a likely scenario, especially if you are using original 5¼" disk drives on your BBC. Many PCs are fitted with only a 3½" drive, and more modern ones are unlikely to have any floppy drives at all.

To use this method you must, of course, have a COM port fitted on your PC, but although these are tending to be phased out, there are still quite a lot of PCs around with such ports. (It may nowadays be possible to conect the BBC computer to USB using special equpment, but it is not straightforward. I have not attempted to cover this possibility here.)

The main inconvenience of doing things this way is simply the time it takes. The fastest serial link the BBC can handle reliably is 9600 baud. At this rate data is transferred from the PC to the BBC at about 6kb per minute. (You might think it ought to be faster, but in practice there are reliability checks on the data, as well as substantial gaps between data packets, and this is the sort of speed you will get.) The Master 512's system disks comprise one 640kb disk and three 800kb ones, making a total of around 3Mb. To transfer this amount of data at 6kb per minute takes over 8 hours. A requirement is patience!

You will need software to transfer files from the PC to the BBC Micro. A good option, if you do not have a program already, would be XFER. This program is written specifically for transfers between the PC and the BBC. A major advantage, for our purposes, is that once the two computers are connected together XFER can automatically write the necessary transfer software into the BBC Computer from the PC. (There has to be software in both computers for files to be transferred.) For completeness a version of XFER has been included in the Method 2 Package so you can have all the resources you need in one place.

You will also need a cable to link the BBC's RS423 port to one of the PC's COM ports. This is not difficult to make, provided you can get the parts and are mildly competent with a soldering iron.

You can download a package from this site which contains all the software you need. The bulk of this package is disk images of the Master 512 system disks, each split into three so that the parts can be saved as files on floppy disks. The idea is that each of these image parts can be written across the serial link to the BBC Computer, and there saved as a file on a BBC format disk. There is also a BBC Basic program, WRSPLTIM (short for "WRite SPLiT IMage"), which itself can be written to the BBC. This program combines together the partial files and writes them to floppy disks, creating the system disks you want.

In detail:

The following describes the process for systems with two floppy disk drives. If your Master 512 has a hard disk, then use this as appropriate.

To create the system disks using the Method 2 Package, proceed as follows:

         If you have not already done so, make a serial cable and connect the PC and BBC using it (making sure it is inserted the right way up at the BBC end!)
    Download the Method 2 Package and unpack the Zip file.

On the BBC Computer in native mode, format several disks in ADFS Large format, using the ADFS disk formatter AFORM. You will need six disks to hold the partial image files, plus one disk which will become the DOS-Plus boot disk. (You will also need three other disks which will eventually become System Disks 2, 3 and 4, but you cannot do anything with these three at the moment.)

[If necessary, you could get away with slightly fewer than these 10 disks by re-using some of them at a later stage in the process after their initial contents have been dealt with. If you have a hard disk on the BBC you could copy the files to that instead.]


Set up the XFER program (unless you are using a different serial transfer package). See below for details about XFER.

    Using this XFER program (or an equivalent) write the partial disk image files through the serial link to the BBC Computer, and save them on the ADFS disks you formatted earlier. The files you need are the ones called M512_n_m where n is 1 to 4 and m is 1 to 3. There are twelve files in all, and you will get two on each ADFS disk. This will take a long time!! (Remember to "*MOUNT" each fresh disk when you insert it. Keep a careful track of which files are saved on which disk!)

Also transfer the file WRSPLTIM. It can be saved on the same disk as a couple of the partial images.

[You do not need any other files from this package. The files M512_X_m are partial images for the DOS-Plus 1.2a boot disk and you can deal with these later if you like. All the *.INF files are information for XFER to transfer the others correctly.]

    Quit XFER on the PC and go to the BBC Computer. The rest of the process is carried out there.

On the BBC in native mode, run the Basic program WRSPLTIM which you have just transferred.

Note: See below if you are using a Model B or B+, or if you have ANFS installed.


Use this program to write the three files M512_1_1, M512_1_2 and M512_1_3 to another (formatted, large) ADFS disk. The program will ask for the name of the first file including the drive. So if the files are to be in Drive :0 enter the file-name:


The file-name of this first file must end in a "1". Once the program has started it will ask for the subsequent files when it needs them.

When the program finishes you have a copy of the DOS-Plus Boot Disk in the drive you have written to. Label it.

    Now use this disk you have just created to boot up the Master 512 into DOS-Plus. (Enter *CONFIGURE TUBE and <Return> for a Master with internal co-processor, or just switch the co-processor on if it is an external one attached to a Model B or B+. Insert the disk in the first drive and press <Ctrl-Break>.)



to start the DOS-Plus disk management program. Use the program to format three more disks, this time in 800kb Acorn DOS format. (The program is menu driven and very easy to follow. The 800kb format is the second one on the list of formats available.)

    Return to BBC native mode. (On the Master, press <Break> and then at the Monitor's "*" prompt enter CONFIGURE NOTUBE and press <Return> then <Break> again.)
    Use WRSPLTIM three more times to write the other images to these three 800kb disks you have just created. Use M512_2_1 to start Disk 2, M512_3_1 for Disk 3 and M512_4_1 for Disk 4.
    Label the system disks! (The other disks you have used in this process can now be forgotten about, re-formatted, etc)

Note for Model B or B+ users: The WRSPLTIM program was written on a BBC Master, and has only been tested on that machine. In the program things need to be done slightly differently for the Model B or B+. (The program has to access the WD1770 disk controller chip directly, but for some reason (which I have never understood) in the Master the registers for the chip are mapped to a different place in the memory from where they were in the B and B+.) This difference has been allowed for in the program and I think it should work on the older machines. However, I have not been able to try it out and I may have missed something. If you have a Model B or B+ as the host machine of your Master 512 system, and you find that WRSPLTIM does not work on it, would you please let me know.

Further Note for ANFS users: There is apparently a problem using WRSPLTIM on a Master fitted with ANFS. It may be necessary temporarily to *UNPLUG the ANFS ROM before using it.

Setting up XFER

You need data transfer software to use with the above procedure and, so that you can have everything together, XFER is included in the Method 2 Package. When you unzip the package one of the directories produced will be called XFER51, and it contains the XFER program.

Note: The PC part of XFER is a DOS program. It will run perfectly well in a "command prompt" box in earlier versions of Windows. On a more modern machine, especially one running a 64-bit operating system, it may be better to set up a virtual machine (using something like VirtualBox along with an older OS) and run XFER inside that.

XFER does contain its own documentation. However this is somewhat out-of-date, and also it describes settings most appropriate for use with DFS on the BBC. We have to use ADFS for the process here. (The files are too big for DFS disks, and it is too messy to split everything into even smaller parts. You must have ADFS to be able to use the Master 512 anyway.)

To set up XFER:


If you are using a Master, enter on it:


and press <Return> then <Break>. (This sets the data pattern to "8N1" – you will not need to do anything on the Model B or B+ to achieve this because it is the default on those machines.)


On the PC, ensure that the values in the XFER.INI file are correct, and edit it if necessary. Lines in this file under the heading [XFer] should include:


Change the value in the first line to "com2:", if that is the port you are using.

The values for "wildcards" and "directories" (both off) are correct for using ADFS on the BBC. If you normally like to use DFS on the native BBC Computer then, after you have finished this system disk process, you could set both values to "on", and that will give you a few more facilities with that filing system.

This value of "handshake" is correct if you have a cable wired up as described here. There are other ways of wiring the cable, and if you have used a different one you may need a different value here. See the details of the XFER documentation in this case.

If you would like to try "baudrate=19200" then that is up to you. However you will not save much time at all, and file transfer may end up slower because of transmission errors.


From the DOS command prompt on the PC set the XFER51 directory as the current directory, then enter:


and follow the on-screen instructions. This will transfer the BBC Basic part of the package across to the BBC Computer, where it can be saved as a file (which it is suggested that you also call "XFER") on a BBC disk.

    If you like you can just continue to use the program from here. On future occasions start by running the BBC program, then when it is going run the XFER program on the PC (without the "-1" command tail).

Downloadable Resources

      Method 2 Package:   This contains all of the system disks images, each one split into three files. Also included are all the further files you need for creating the disks from them. (Note that the files M512_X... are the part images of the older DOS-Plus Version 1.2a boot disk, which you can create as well if you wish – use exactly the same method as when creating the Version 2.1 boot disk.)

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