| Posted By
TLC
on 2011-08-29
15:40:48
|  Hungarian Kernals
Hi guys!
I'm quoting part of a message sent to the cbm-hackers mailing list. All in all - seems like we Hungarians were in fact provided with two different localized (national charset equipped) Kernal versions.
--->
To keep the story short: I took a Plus/4, a modified rom card and two
Hungarian Kernal roms (the 318030-01 and an Eprom) today, and made dumps
of the chips at last. The ultimate result is that there were in fact two
different Hungarian 264 Kernals around. The mask rom and the other
version - taken from a 1986 Plus/4 -, much unlike I suspected, don't
carry the same content.
I've passed the dumps on to Bo Zimmerman, and he already acknowledged
them so I'm sure they'll appear on zimmers.net's file area pretty soon;
yet I also copied all the stuff to a "site" (a Linux box beside the
desk, that is...) so that if people want, they can have a look at the
files. The link is http://coroners.no-ip.hu/stuff/p4kernal . (The
machine isn't up all the time, but it'd always get back online in some
hours at the worst case).
318030-01 is based on 318004-04, replacing some graphical characters only.
The other (so far only found in eprom) version is originally 318004-05,
and it also contains further modifications to the character set. The one
that I have here is in a NEC 27C128, whose datecode appears to be 8614
(see photos) ie. it had to be programmed after the spring of 1986.
I've made a quick-and-dirty diff routine in plus4emu so that differences
could be spotted. diff.png shows the original charset, 318030-01, and
the later eprom version (in that order from top to bottom). Red: char of
original set and dump 1 don't match. Cyan: char of original set and dump
2 don't match. Yellow: char of dump 1 and dump 2 don't match (...a
special case appears: dump 2 only modifies characters that were not
modified in dump 1).
As to how and why these (new) differences in the character set?
Honestly, I don't know (...I have no idea about especially the few
graphical characters that have been modified). Also, someone's yet to
find a Plus/4 with the first and a C16 with the second version; I could
never encounter either of those combinations yet.
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Posted By
MMS
on 2011-08-30
15:37:35
 | Re: Hungarian Kernals
Nice finding! 
Looking at the charsets, the changes are kind of improvement and "bug-fixes", probably based on some customer or marketing feedback.
A and P in the new version seems to provide more space in the closed-in small area, thus chars are more readible from a bigger distance. "i" is the same, probably froma distance it was hard to distingiush from 1, but by adding some more pixels it became well noticeable "i" on CRT TV from a distance .
The 2 special characters also seems to be a bug initially, as they look exactly the same in the old version as the characters next to them. So, they make them more different.
Nice to see, that even in such a "fix" hardware the quality improvent circles ran well
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Posted By
Luca
on 2011-08-31
13:55:14
 | Re: Hungarian Kernals
Nice find, just added'em to the hardware page. The EPROM seems to be based on the original early one.
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Posted By
TLC
on 2011-08-31
14:47:20
| Re: Hungarian Kernals
That's great man, thanks!
If the eprom was based on some early Kernal version, well, that looks interesting. I diffed both images to official PAL kernal images, as found at http://zimmers.net/anonftp/pub/cbm/firmware/computers/plus4. 318030-01 (ie. the earlier one) looks to be based on 318004-04. The eprom dump is definitely later, both because the eprom itself has been manufactured in 1986, and because the dump seems to be based on 318004-05 ie. the last known PAL Plus/4 Kernal version. I base those assumption on the fact that either respective comparisons (318030-01 vs. 318004-04 and the Eprom vs. 318004-05) only resulted in hits in the $d000-$d7ff area ie. the character generator.
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