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Siemens PG750 - a portable 386 PC with a CRT color display ... 
Saturday, February 29, 2020, 01:30 PM
Posted by Administrator
Recently I purchased a portable PC, a Siemens PG750, which was in fact used as a S5 PLC programmer. But regardless of it, it can be used also to play DOS games, at least EGA graphics compatible ones.
This portable device has a Texas Instruments Graphics Adapter (TIGA) named Higraph I, based on a TMS34010 chip. It is very hard to find TIGA compatible software, mostly only ACAD 9 and 10 drivers. But the TIGA card offers higher resolutions similar to a VGA card. So I am still looking for TIGA GEM 3.0 and Windows 3.11 drivers.
The original hard disk drive contained MS-DOS 3.30 and Personal CP/M 2.0 (S5-DOS) - these two OS can be selected after booting of the PC is done:


You can't access the CP/M filesystem (2nd partition) with MS-DOS, but with Concurrent DOS 3.2, I was able to access both partitions at the same time:


The PG750 has originally a combo floppy drive with a 3.5" and a 5.25" floppy. Unfortunately this Canon MD5511 drive was faulty (the 5.25" part). So I replaced it with a modded Gotek drive:


There is no left space for additional drives, because only one 5.25 drive bay can be used:


I didn't find so much additional information about the device itself, it seems to be a bit rare, even the original manual of the PG750-386 can't be downloaded anymore (but still for the 486 CPU version).

Related link points to the manual for the PG750-486.
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Micromint SB180FX ZRDOS and file transfer adventure 
Sunday, February 16, 2020, 07:36 PM
Posted by Administrator
While testing my Micromint SB180FX again, I was curios how I can transfer files from and to Micromint floppy disks.
This is really an adventure, also because of ZRDOS (or ZSDOS, as some told me).
Because there is no PIP nor COPY command for files, I was a bit helpless how I can transfer files on a new disk, also because my SB180FX has different floppy drives.
Because of the different floppy drive formats (A: = 40 tracks, B: = 80 tracks), I was not able to copy files from and to empty 40 track floppy disks.
But RAM Disk (Memory Disk) to the rescue, N: (and M:) is a default drive for the build in RAM Disk. I didn't know the initialization program first, but after try and error, I found NDSKFX, just starting it with 'I' means initialize the RAM Disk (only after that, you can copy files onto it, if you know a copy command).
VFILER was also present, so I was able to copy VFILER.COM to the RAM Disk with the help of VFILER itself, also DIR.COM and also FVCFX.COM (this program can format and copy diskettes).
Now, changing to N:, I was able to make a new blank diskette.

My final goal was to copy UNIFORM (multiple disk formats and transfer utility) to this blank disk, but I got only a "sb180b30.image" file - which was in fact a binary unpacked IMD disk.

What was missing ? How to transfer files from and to that image file ?
CPMTOOLS to the rescue ... just creating a new entry in DISKDEFS would make it:

diskdef sb180
seclen 512
tracks 80
sectrk 10
blocksize 2048
maxdir 128
skew 1
boottrk 2
os 2.2
end

Now I was able to extract the files to the hard disk drive, then I changed the computer (going to my disk transfer PC with 22DISK). Having the files, I used 22DISK and the format AMP2 (SB180 has the same 40 tracks format) and copied the files onto a real (blank) diskette back. Mission accomplished, but it was a bit exhausting.

This is the screen of UNIFORM:

Btw. to make a floppy bootable, you have to use this command: SYSGENFX PUTSYSFX.COM
(It will write the system image onto a floppy's boot tracks.)
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Merry XMAS and a happy new year 2020 ! 
Wednesday, December 25, 2019, 02:30 PM
Posted by Administrator
While surfing around and looking for a nice xmas demo, I found a 64KB DOS demo from an event named "The Party" in 1996. It has a nice soundtrack and it has some action on the screen ;-)

See related link below for a download possibility.

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A real classic computer game - ELITE ... worth to be revisited ! 
Sunday, September 29, 2019, 11:30 PM
Posted by Administrator
This is really a classic computer game, famous or at least well known, but nowadays almost forgotten. ELITE was one of the first open world game for PCs and home computer.
That means almost eternal game fun/game play, if you want.
Published from Acornsoft in 1984 first, Ian Bell and David Braben created this space simulation/trading game with some real new features for its time, like wire-frame 3D graphics (MCGA version has textures/filled areas already!).
It can be played on several platforms, and so also on PCs running MS-DOS.
The CGA version (which runs not quite bad on a standard XT) looks a bit ugly, but is well playable, too:


Surprisingly, EGA and VGA version (Elite Plus) does not visually differ.

EGA:


VGA:


Only the MCGA version (Elite Plus) looks way better:


The best of all - this game is meanwhile legally downloadable, see related link.
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Further tests with Concurrent DOS 386 3.0 (still with PCem) 
Sunday, August 25, 2019, 02:00 PM
Posted by Administrator
Another test round. Tried it first with an emulated 486. Didn't worked.

Then, I choosed to emulate a Compaq Desktop 386, which was somewhat a success.
You have to look for a SETUP disk first, because there is no "build in BIOS setup".
I still got a "memory mismatch", because the setup program didn't recognized the emulated RAM amount, but you are able to press at boot time F1 to continue anyway.
Then I was able to install it - but not with the disks from winworldpc.com !
The disks there didn't had the correct boot sector - but nobody there recognized this.
I downloaded working disk images from bitsavers.org, they were in IMD format, but you can convert them with IMDU to IMA/IMG files. But the "N.CMD" was missing, get it from the winworldpc.com disk image. Or just copy the boot sector of the bitsavers.org disk image to the one from winworldpc.com - a bit ugly, but works too.

I was a bit surprised it returned DOS version 3.31 (NOT 3.30), see here:

Had to patch CHKDSK from DOS 3.30 to run it, free memory looks similar to Concurrent DOS XM:


I tried PSION CHESS again (choosing CGA display), and it looks better (correct color palette now). Also, if you switch with Ctrl-2 to the next window, I was able to start programs like FM, showing the free memory:

As you can see, there is also RAM occupied from the "FM" process, in parallel to the still running game. You will not be able to switch between EGA or VGA games still.

Related link leads to a Youtube video with an advertisment of Concurrent DOS.
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