Scor­pio News


January–March 1987 – Volume 1. Issue 1.

Page 54 of 63

Customizing the CBIOS

The CBIOS is the area where most can be done to make CP/M more user friendly. I recently bought an Alphatronic PC – A Z80 CP/M machine that was very well made and selling at a bargain price. I had thought that it would be useful as a second machine. I kept it for about six month, and then sold it to a friend who had previously been using a PET. He thinks that it is fabulous, so why did I sell it? (I did put CCPZ onto it.)

Well, I found that I just could not put up with a machine that had no Type Ahead, no screen dump, no screen editing, limited paging (from CCPZ), limited function key support, no backspace key, kept changing ‘care’, and had partly ROM based BIOS. The supporting utilities for copying and formatting were not very good either – pretty screen displays, but no verification, no information on progress, and a bug or two. At least when I sold it it had CCPZ and some public domain utilities to help. It made me realize just what some people have to put up with.

A number of BIOS’s are available for the Nasbus/80-BUS machines. I have used BIOS’s by Gemini, Richard Beal (SYS) and MAP80 Systems. I have no knowledge of Nascom CP/M BIOS’s so T cannot comment on them. The three. BIOS’s mentioned are all very good and provide features that are rare., if not unique, on 8 Bit CP/M machines. Fortunately, MAP and SYS BIOS’s come/​came with source code. (Unfortunately SYS cannot now be purchased, but I believe that there are quite a few about.)

If I can ride one of my hobby-horses here – Whilst I fully understand the problems of copyright and pirating, I feel that it it is a completely retrograde step to withhold the BIOS source code from system purchasers. The vast majority of users are being penalized for the sake of the oud dishonest person who could probably be dealt with effectively by the law anyway. I feel that piracy is being made the excuse for trying to prevent people from expanding their systems except the Gemini way. SYS at one stage included Winchester support, but later this had to be removed. (Because users didn’t need to go to Gemini for a new BIOS or to buy a Winchester?) Then SYS itself was withdrawn because of Copyright. problems. (See App. 2 Ref 4)

The new GM849 card seems to me to be a similar case in some ways. I recently wanted to purchase a spare Disk Controller card for several machines at work that are in heavy use, and I was annoyed to find that the GM849 card that supercedes the GM829 needs version 3.4 of the BIOS to run it. (When the CP/M was upgraded to Version 3.2 BIOS at work a few month ago there was no mention that it would not drive the 849 – nor was there a mention of the 849). The CP/M on the machines in question cannot be easily replaced due to special custom routines, so I will have to try to alter the CBIOS to support the 849. This sort of work I can do without.

Logically one would expect that Gemini would want to offer the best BIOS available, but their BIOS does not include a number of uesful features such as locked EDIT and extended Screen Paging, and without the source code, it is of course impossible to customize it for additional features such as Clock support, or the type of keyboard feature described later. Neither are MAP products supported, again denying users of the BUS the most flexible system. Once one it accustomed to such features, it would be difficult to return to a BIOS without them appreciate that there must be limits to what can be provided as ‘CONFIG’ options, but I do not see that as any reason to deny the users ie: CUSTOMERS, the facility to do their own customizing.

Fortunately I have been able to combine many of the features of SYS with the MAP CP/M 2.2 BIOS, and the added in some of my own routines to provide myself with the features that I want. (For personal use only.) Customization like this takes a lot of time though, and obviously would not be possible for many users, even if the required source codes are available. The restrictive approach must be denying users the best operating environment, and this could be detrimental in the long run.

Page 54 of 63