MTX Plus⁺ CP/M

I had originally thought that getting CP/M running on MTXPlus+ would mean writing a custom BIOS from scratch (see below).

However, Martin has been busy again and ported Andy Key's REMEMOrizer ROM code to MTXPlus+. The screenshot shows MTXPlus+ booting CP/M from a Compact Flash card which contains a copy of Andy's CP/M system disk included with REMEMOrizer.

At this point, the software is unfinished - for example, the system does not currently support Memotech FDX/SDX colour attributes, but Martin has made a great start. The system can run CP/M transient programs such as "PIP" and "STAT", third party programs such as CRCK44 as well as Memotech utilities such as MTX/MTXL which switches the system into 40 column MTX BASIC mode. The photos below are a selection of the screen displays from Martin's TV - the images give a flavour for how the display looks, but do not do justice to the video output - the quality is much better in reality.

The output from "STAT DSK:", showing the structure of the disk (CF card partition) as seen by CP/M - copied from REMEMOrizer : 65472 x 128 byte Records, i.e., 8MBytes 512 Directory entries 2 Reserved tracks (for CP/M)
With its 512KB of RAM, MTXPlus+ also supports a Type 52 RAM disk like REMEMOrizer. This screenshot shows the system running the RAMDISC submit file from REMEOrizer. Drive "F" has been created as a 320KB RAM disk and a number of CP/M tools have been copied to it, allowing them to run from RAM.
Screen shot of the system running NewWord with VDEB.DOC open for editing.
Martin has been busy again . . . . . NewWord now running in colour - the attribute code is still not finished, but this is a big step forward.

 

Display Comparison
REMEMOrizer VGA Output Aspect Ratio 4:3	MTXPlus+ NTSC RGB Output Aspect Ratio 16:9

Original Concept

My ultimate aim is to get CP/M running on MTXPlus⁺ to enable me to run some of the large range of software that is available for CP/M. Initially, I will be using CP/M 2.2 - the same version as used by the original Memotech FDX and SDX, as well as the BBC Micro, but may ultimately try to migrate to CP/M 3 which supports memory paging, subdirectories and file date/timestamps.

My Memotech MTX focused CP/M pages provide a high level overview of CP/M, but the key principle is that CP/M was written to be transportable, different systems can run the same software programs with only a limited quantity of machine specific programming at Operating System level. All CP/M systems have their own Customised Basic I/O System (CBIOS, or just BIOS), used to interface the machine specific hardware with the high level CP/M function calls for such items as the keyboard, video display and disk drives.

• More details on the  MTXPlus⁺ BIOS page

This page is a repository for useful information that may be used while developing the MTXPlus⁺ CP/M BIOS. A number of Digital Research documentation for CP/M 2.2, including the CP/M 2.2 System Alteration Guide can be found on my CP/M manuals page.