Peter's z80.eu site blog
Using MS-DOS 4.01 with virtual machines is a NIGHTMARE ! 
Saturday, February 1, 2014, 02:00 PM
Posted by Administrator
This is really weird. There are some web sites offering a floppy disk image of MS-DOS 4.01, but you can't do anything with it - except with a real PC.

Meanwhile I own an IBM PC XT, and I wanted to reinstall a DOS.
The DOS I used before was IBM DOS 3.2, but this DOS version's keyboard driver was not really compatible with my 101-key keyboard from Cherry (which can be configured also to be used with a PC XT, not only with an PC AT machine).
So I had the idea to try other DOS versions.
I tested Tandon DOS 3.3, but this version was NOT really usable. You are not able to transfer the MS-DOS system itself with FORMAT /S, instead, you have to use "FXPREP". This utility from Tandon did not really format my MFM HDD correct, it doesn't recognized most of the bad blocks of the HDD (it marked it again as usable.... not really helpful).
You have to use SPINRITE (or similar software) again to correct this.

So I had the idea to use MS-DOS 4.01... and then the NIGHTMARE began.

Because the offered MS-DOS 4.01 boot floppy disk images were 720KB or 1.44MB disks, I had the idea to convert them by using a virtual machine.
I tried VMWare Player 5 (and also later some other versions), but VMWare is NOT able to boot from a MS-DOS 4.01 boot disk - this is very strange.
So I took Oracle's Virtualbox again, and booting from the floppy worked.
BUT. After transferring all DOS files to the virtual harddisk, I was NOT able to copy them back to a (virtual) floppy disk drive. Virtualbox always assumed I have a 1.44MB capacity HD floppy drive, but I needed to write them back to a 360KB formatted floppy, to use it with my IBM PC XT.
So VMWare player is NOT able to boot from it, Oracle Virtualbox is NOT able to write it back to 360KB floppies. I am really disappointed from both virtual machine solutions.

This is all related to MS-DOS 4.01, older or newer versions will work also with both VM software.

But there is hope:
You have to use WINIMAGE from Gilles Vollant, load the (bigger) disk image, delete some files to let the sum of the files not greater than the target floppy capacity, and then change the "Floppy Disk Format" itself just by selecting another capacity in WinImage's function for exact that case. After saving the new disk with another name, it will be possible to use this - in my example 360KB - floppy disk image to boot MS-DOS 4.01 with Oracle's VirtualBox or with MS Virtual PC 2007. And later on with my PC/XT also :-)


Btw. - MS Virtual PC 2007 (after editing the .VMC file for an additional floppy id in section "super_io") is the only Virtual Machine software which can run MS-DOS 4.01 also from HDD ! You have to disable almost all "modern" things in BIOS (press DEL at the very first seconds of boot process), e.g. 32Bit Access, LBA, Hardware Virtualization a.s.o. - then it really worked, even the original INSTALL process, which copies vvveeerrryyyy slowly files (be patient, don't reset, just wait). You will be rewarded with DOSSHELL ;-)

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"Free" mail service mail-online.dk is a deceptive package - a warning ... 
Wednesday, December 25, 2013, 02:30 PM
Posted by Administrator
Years ago, I have taken a free mail service, mail-online.dk, because I needed a second mail address for registering some programs etc.

I have taken this account also for playing an online game.
Now, 14 days earlier, mail-online.dk informed me, that it's not free anymore, instead, I have to pay approx. 7 Euros per month, and I have to take at least 6 month at once.
This change will be effective from January 1st 2014.
Regardless of the real short warning period, the minimum period of time I have to purchase (6 month!) and with that exorbitant high price. So I got a new problem, because my game vendor are not willing to change the email address of the game account in a few days. In fact, I am not sure they will change it fast enough, and then I can't receive any confirmation mails anymore.
The maliciousness of this is, that both, mail provider and game vendor, will not work hand in hand and so the only one who will be spoofed is me.
I guess the game vendor has enough players so they are not interested in keeping customers (who paid money for the game) anymore.
Unfortunately that game was the only one I got some fun while playing at the moment.

The bottom line: Do not trust in free mail providers.

P.S.: mail-online.dk has a sister company, weekonline.com (so I don't recommend them, too)

P.P.S.: I managed to tranfer my above mentioned game account. It's now tied together with a new mail-account - but not a "free" mail-account anymore, and no, not an expensive danish one.
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Good news - Supercard Pro is now available 
Saturday, December 21, 2013, 09:00 PM
Posted by Administrator
See http://www.cbmstuff.com/proddetail.php?prod=SCP for more details.

Now you can buy the Supercard Pro and there is already a bunch of implemented features.
The SuperCard Pro software is still a work in progress, it will be updated continuously.
New file formats will be supported soon (e.g. often used floppy disk formats) hopefully.
Stay tuned to hear again from them soon.

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Sega Genesis Frogger (but SNES still rulez!), run with a free online emulator 
Sunday, December 15, 2013, 03:00 PM
Posted by Administrator
Just take a look at Frogger run on a Sega Genesis:

You will notice a slightly less acceptable graphics quality, although it's also good playable.

So SNES still rulez... :-)

For you all without a real Sega Genesis console, try it online at ssega.com.

This site provides you a full access to all known Sega Genesis Games but without the need of installing any emulator. Really nice, isn't it ?

For a comparison, see my other blog entry about SNES Frogger.

You can play SNES Frogger also online, snesbox.com will make it possible...

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TI Programmable 58 - powerful but always losing memory 
Saturday, November 23, 2013, 12:00 PM
Posted by Administrator
This calculator was a milestone in terms of programming capabilities, but not a success.
It was soon (1.5 years later, 1979) replaced with a similar calculator model but with a persistent memory - the TI-58C.
There was also a big brother with more memory and a magnetic stripe reader, the TI-59.
Both can be upgraded with special modules, e.g. a mathematics cartridge, or even custom roms for aviation.

Compared to other TI calculators of the same era, battery compartment is different (see the two latches/clips inside), battery pack BP-1A differs from comparable battery packs (e.g. for the TI-57) also.
Don't miss the "cleaning a TI-59" page from Marek Czeszek if you're a collector of these wonderful devices.

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