Peter's z80.eu site blog
Raped IBM PC/XT on Youtube, ignorance for details at it's best 
Saturday, October 13, 2018, 12:00 PM
Posted by Administrator
Some people might have cool ideas, also to modify originals for a new functionality.
If someone try to modify an original IBM PC/XT to implement a new PC in it, it might be still worth to mention it, especially if the conversion to a modern PC is subtle (not intrusive).
So if someone do this but let the PC still look like the original, and make it possible to use the original floppy disk drives (but with the modern hardware inside), it would be even cooler.

The opposite is ugly. If you destroy half of the original case (e.g. the backside) and if you just use the floppy drive bezel, but remove the rest of the drive(s), it sounds like a brutal modification, without any style.
And even more worse, they use the floppy drive bezels, but mount them reverse (upside down), see the picture taken from the Youtube video:


But judge yourself about the (not well done) conversion, see "related link".

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Finally I managed to re-active my Central Point Option Board... 
Sunday, September 16, 2018, 10:00 PM
Posted by Administrator
It works now, but it was quite a high effort to get it running.
First, I had to figure out that a Compaq Portable has REALLY not much space inside.
I added first a 256KB RAM card, because otherwise some software can't be started with only 256KB RAM (on board).
But then I recognized that the original video (CGA) card was fixed with a horizontal arranged screw, but the hole for this screw was ONLY in slot #2.
In slot #1, the original floppy disk controller resides, and guess, the cables are really short. So to connect the floppy drives to the first version of the Central Point option board, I had to look for much longer cables, but with two old style shugart connectors and with an AT style connector at controller side. Because this was a pain to arrange it, I decided to exchange the A: and the B: drive connector (so the cable didn't crossed itself). Also, the original floppy disk controller is really "full height", so no space to arrange things more flexible.

Finally it runs, at least with older TRANSCOPY versions (2.x):


This is really tricky to arrange:


And this is the resurrected card (a 16MHz crystal was broken, so I replaced it).


It is even possible to copy special Apple II floppies, see related link.
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And another CP/M chess program: MYCHESS 2.3 
Friday, September 14, 2018, 02:00 PM
Posted by Administrator
Btw. another strong playing chess program for CP/M is MYCHESS.
The latest version is 2.3(b). It comes with a configuration program (MYCONFIG.COM).
At least you can change the cursor positioning ESC sequence, which makes it possible to place the pieces on the right screen position ;-)
Unfortunately the preconfigured MYCHESS.COM uses already very different ESC sequences to show block graphics I guess, see below.

Starting screen:


Game play screen if MYCHESS.COM is started on MyZ80:


Game play screen if MYCHESSN.COM is started on MyZ80:


Game play screen if MYCHESS.COM is started on VirtualKaypro (emulating a Kaypro 4):


Btw.: Using VirtualKaypro (Java based) is a pain. You have to know that it runs only with country setting "English (USA)", not with a german setting, because the class function for converting the time to a string presumes only US date/time format.
Also, you can't use a directory name containing blanks.
And finally, preloading a "blank" virtual floppy disk with files using the java program archive "format.jar" is also chaotic, because there is no description for the parameters you have to use. The "raw" format is NOT a real binary sector-by-sector raw format, instead, it presumes to have a header, too.

Related link points to a ZIP file with all CP/M files of MYCHESS 2.3b.

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Ancient chess programs: Sargon and Sargon 2 
Wednesday, September 12, 2018, 02:00 PM
Posted by Administrator
Well, usually chess programs must have a beautiful user interface to be played, as well as playing chess very well (so not only "Minimax" algorithm, but also some openings).
Looking back to these old days of CP/M computers, screen graphics were rare and properitary programmed. Usually the screen output was characters only.

Sargon is a well known, famous chess program for vintage computers. The first version was SARGON for Z80, and runs (adapted already) on *any* CP/M 2.2 computer. The screen output is ... unique (not beautiful at all). But it is playing chess very well, I lost a few games even with Level 1.

SARGON looks like this:


SARGON 2 starting screen:


... and board display (this time, Sargon started first):


Related link offers the CP/M binaries. It was taken from >Udo Munks download page< (the files from the disk image there can be extracted with cpmtools, disk format is 'ibm-3740', use 'cpmls' and 'cpmcp').
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REVERSI - A QBASIC program from 1990 ... playing stronger as you think 
Wednesday, August 1, 2018, 10:00 PM
Posted by Administrator
Almost every Windows 3.x user knows REVERSI aka OTHELLO as a 16-Bit Windows game.
But Microsoft published the same game also as a QBASIC game.
QBASIC was part of MS-DOS 5.0, development of MS-DOS 5.0 reached beta level in 1990.
I was curious and tested REVERSI.BAS from that MS-DOS 5.0 BETA (which is quite the same as one year later in the final MS-DOS 5.0 version), and guess what happened...

I lost it several times even with 'Novice' setting. Finally I managed it to win, but hell it was not really easy. And I did not tried the 'Expert' setting...

Just judge yourself about the game playing strength of that program and start QBASIC from DOS 5 again (e.g. with the help of DOSBOX, which is running even with Windows 10).
Or compile it with >QBASIC64< (which compiles it to a native Windows program).

Related link points to the source code ZIPped.
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