Getting Started 2: Z80 Co Processor and CPM

The BBC Micro was a modular design. It could have a co processor module installed. Software could then run on the coprocessor with the main system CPU taking care of I/O. This gave the system a speed boost. The BBC came with a 6502 processor, but the design was such that different processors could be used in the coprocessor. At the time a popular CPU Was the Z80.

This was tested on the model BBC Model B w8271 FDC. It should also work on the Master 128.

Ensure that Z80 is selected in the Tube menu. Insert the disc cpm1.dsd into drive :0/2 and boot it (CTRL-Break). This will bring up the CPM welcome and command prompt. It looks very much like a very old version of DOS.

The CPM discs supplied are the installation discs. The files can be copied to discs in logical groups using the PREPARE command. This requires some CPM formatted disc images, which b-em doesn't seem able to make, so we can use the following procedure. Make a copy of cpm7.dsd, call it cpm0Blank.dsd. Insert it into drive 1/3, make sure the write protect disc :1/3 is not selected in the Discs menu and in CPM delete all the files. The colon is on the same key as the star, unshifted.

B:
ERA *.*

Reply Y. DIR should confirm there are no files on the disc. Eject it using the Disc menu. Now create 12 copies of this blank disc image named cpmA.dsd - cpmL.dsd.

Now the working copies can be created. Run:

PREPARE

Page through the information, and at the menu press M to make a copy of everything. Press space to accept. Insert cpmA.dsd which was created, and ensure it is not write protected. B-em write protects images by default when they are inserted, so either remember on each image to remove the protection, or switch off the default while making the images. Do not format the image. Say Y to copy the CPM system on to the disc - this allows CPM to be booted from any of the discs. While it is possible to prepare all the discs at once, they aren't created in the same order as they are listed in the menu, which can be confusing. Remember drive A is :0/2 in the menu, and B is :1/3.

When complete the following 12 discs have been created:

1. A - Graphics and Utilities

   See the Z80 Second Processor User Guide for more information.

2. B - Memoplan

   This is a word processor. See the Memo Plan manual for more information. It is controlled using the function keys, CTRL-f9 to exit.

3. C - Fileplan

   Card index program.

4. D - Graphplan

   Spreadsheet with emphasis on finance/business. It can draw charts. See the Graph plan manual for more information.

5. E - Basic

   BBCBASIC
CH."WELCOME"

   This loads the same set of programs as on the BBC B welcome disc.

6. F - Cobol

   See the CIS COBOL Language Reference manual for more information.

7. G - Nucleus definitions

   Nucleus is a menu/forms/reports generation program. See the Nucleus System Generator manual for more information. This creates the data structures.

8. H - Nucleus parameter file

   The parameter file holds information about the structure of the programs created in Nucleus.

9. I - Nucleus reporter

   To generate reports on the data held in Nucleus.

10. J - Accountant

    A financial book keeping program. See the Accountant manual for more information.

11. K - Accountant data

    Data disc for the above program

12. L - Start of day

    Part of the Accountant package.