Additional Script to Create BIOS ROM

[jca]

I propose the addition of a new script in https://github.com/MiSTer-devel/PCXT_Mi ... in/SW/ROMs
This is version 3 dated 05/09/86:
Faster memory test on Power Up/Reset.
Support for extended keyboard.
Supports 360K and 1.2M floppies. Only 360K and 720K on PCXT core.

The ROM produced is named IBM-5160-V3.rom.

As an apart I discovered that the IBM ROMs created by the official script and the new one contains IBM Cassette BASIC and can be started by pressing F8(RomBoot) on the boot screen of XTIDE Universal BIOS.
Time to add a cassette interface to the core

[Malor]

It's funny to me that even PCs could use cassette tapes. That's all I used at first with the TI 99/4 and 4A, so I got real used to it. But I think of PCs in that era as being massively expensive machines that all had at least floppy disks.

[jca]

I did not know about it myself. I just learned about a BASIC in the IBM BIOS while looking for the BIOS from 1986. It was a cassette BASIC and if you did not have floppies/hard disk the PC would directly boot into BASIC. That would have been a real expensive BASIC machine as you said.

[Malor]

The BASIC in ROM was a unique feature of actual IBM machines at that time. PC-DOS (IBM's version of MS-DOS) included the "BASICA" program (Basic Advanced, I believe), which required and extended the built-in ROM. All the clones were stuck with the mostly-compatible GWBASIC.

I have the idea that porting from BASICA to GWBASIC had some pain points, that it wasn't just a 1:1 correspondence, but I can't remember any details after so long. I never worked much with either.

[jca]

Interesting site about IBM BASIC.
https://handwiki.org/wiki/IBM_BASIC

[jca]

More information on the type of floppies supported by BIOS 05/09/86 which is the version of 01/10/86 with bugs corrected.

IBM Part #62X0851 (in U18) and #62X0854 (in U19) - dated 01/10/86. Supports 360 KB, 720 KB, and 1.2 MB floppy drives. Note that whilst 1.2 MB drives are supported by the BIOS, the supplied floppy controler in the XT does not support high-density drives.
IBM Part #62X0890 (in U18) and #68X4370 (in U19) - dated 05/09/86. Sames as previous version, One known problem with this BIOS version is that some third-party floppy controllers fail to boot a known-good 1.44 MB floppy disk.

[jca]

This post is for users who don't have Linux or don't want to install Python on their Windows system, sorry Mac users.

Download the zip attached in the first post.
Unzip it to wherever you want.
Open the make_rom_with_ibm5160-V3.py with Notepad++.
If you don't have Notepad++ Notepad will do but the screen will look messed up.
Locate the line with URL =.
Copy the web address, paste it in your browser and press Enter.
A zip file will be downloaded; unzip it.
You will get 2 x .BIN files and a README.TXT file.
What interest you are the .BIN files which are the binary dump of the 2 BIOS chips used on a real PC/XT.
The 2 chips are U18 and U19 and you will find their reference in the name of the BIN files.
For simplicity I will use U18.BIN and U19.BIN in the next following lines but you will have to use their real name.
Open a command prompt (CMD).
Navigate to the location where you placed U18.BIN and U19.BIN.
Type the following command:
COPY /B U19+U18 IBM-5160-V3.ROM
And yes U19 comes first.
Your BIOS is now in IBM-5160-V3.ROM.

[bbond007]

This post is for users who don't have Linux or don't want to install Python on their Windows system, sorry Mac users.

I did not feel like installing Python on my Window systems, as All MiSTer users have a Linux with Python available.

F9 console or SSH... So far running those BIOS scripts has worked just fine for me on the HPS Linux.

Mac systems come with SSH...