rhialto: Me under a waterfall (Default)
The SuperPET is a version of the Commodore PET which has been outfitted with an extra 64 kilobytes of memory and a 6809 processor. There is some nice software for it from Waterloo University in Canada (interpreters for various languages, such as Basic, Cobol, Fortran, Pascal and APL, and an 6809 assembler development system). Unfortunately, this software checks for the presence of an undocumented chip, the 6702. Since I wanted to add SuperPET emulation to VICE, something had to be done about emulating this chip.

Over the last months, several people on the cbm-hackers mailing list have helped to work on this issue. We used, over time, various approaches.

The presence of the dongle was checked by writing values to a memory location (which was part of the chip) and reading values back, and checking some complicated properties that must hold. (More about that below).

One approach was to identify the location of the dongle check routine and "disarm" it. This can be done by hooking in the emulation of the JSR opcode, and check if it happens to jump to the offending routine. If so, it doesn't actually do that, but instead just sets the registers to what they should be to "pass", and continue on. This approach is slightly complicated by the fact that there is bank switching involved (the relevant addresses may be the same but if the bank number is different, it isn't jumping to the same code) and that there are different calling methods used. There are different versions of the various language processors too, so this increases the size of the list of addresses/bank numbers to check. Nevertheless, this method works.

A more efficient approach is to patch the actual programs themselves, to simply remove the dongle check. This is also useful because there are SuperPETs in the wild that don't have their 6702 dongle chip any more. In the first SuperPET version, it was on a small separate board and may have gotten lost. At least one 6702 was destroyed for analysis by the visual6502 team. The dongle check routine can be stubbed out, but this procedure is complicated by the fact that there is a routine which checks the dongle check routine!

There were approaches from the other end too. Dave Roberts made a C version of the dongle check routine for analysis. He used a Monte-Carlo simulation to find values to return from the dongle that would pass the check. This method would simply ignore whatever was written to the chip, and simply regurgitate a fixed list when it was read. He was luckier with this than I was, since he found several working sequences, but his program gave me none at all. Therefore I tried a less random and more exhaustive search (with some branch-and-bound tricks of course) but that didn't really get anywhere.

Read more... getting more detailed here! )


Mar. 28th, 2012 09:36 pm
rhialto: Me under a waterfall (Default)
I'm burning some incense in memory of Isabelle's birthday today. She would have become 47.
My sweetie pea. Rest in sweety peace...


Mar. 1st, 2012 10:08 am
rhialto: Me under a waterfall (Default)
I've been thinking... recently I acquired a ZoomFloppy and a uIEC/SD. These are quite modern electronics with microcontrollers, made exclusively to be used with old electronics like the Commodore PET and 64. There is even a Turbo Chameleon 64, ostensibly a cartridge to connect a VGA monitor to a Commodore 64, but in reality an FPGA on which you can just as easily load a MiniMig (Amiga re-implementation).
This juxtaposition of different eras of electronics is effectively an enormous anachronism, so the name that sprang to mind for this concept was "anachronics".

rhialto: Me under a waterfall (Default)
At my sort-of work at the university, for a professor-emeritus, we recently had a disk disaster with a zfs raidz2 array on a FreeBSD 8.2-STABLE machine. Despite its supposed redundancy, there are (apparently only) 2 blocks with checksum errors, which prevent the storage pool from being mounted (imported).  Even import with rollback (losing a few seconds of transactions) doesn't work. And the former Sun has always been so proud of their reliable file system that they never saw the need to write recovery programs.                                       

Anyone who could take a look at it, or know someone? Of course... no budget... but you'd save years of work...
rhialto: Me under a waterfall (Default)
I hate songs such as "All I want for christmas is you". Bah.
rhialto: Me under a waterfall (Default)
FYI, I have made a [syndicated profile] bofh_feed  on dreamwidth. No, there wasn't a pre-made one on the Register web site, I made one from their search page.
rhialto: Me under a waterfall (Default)
Today, the building society had new windows installed in my flat. There had been a timetable for a while, placing my flat in this week, but no more precise than that. That was rather inconvenient of course since this was one of the few times I would be away during the week (returning from BiCon).
Fortunately I could arrange it for the friday - I'd be home at least and have some time to evacuate the space near the windows (up to 3 metre).
They'd start at 7.30... uncomfortably early, but I managed to get up at 7 or so. But they only arrived just before 8. Within 15 minutes, they had removed most of my windows. The only stuff left were the outermost frames, which were attached  to the walls and had to be forced.
Putting the new stuff in took a bit longer. At about 14.00 they were finished with both sets of windows. Fortunately there was no rain, but even if so, they did the living room window first. The balcony window isn't as susceptible to rain, as there is the higher balcony protecting it. But it was still all open and cold for several hours.
To clear the space near the windows, I needed to move my very large sofa (fortunately it is in segments) and a cupboard that has all my CDs and lots of VHS tapes and other small stuff in it. That was the most annoying part. I also had to clear the Amiga 4000 off the desk in the bedroom. The top of the desk stretches along most of the wall, and can't be removed, but at least the workmen (I didn't spot any women in their team) could stand on it. Removing the Amiga 4000 leaves such a nice free spot, I'd like to keep it that way, actually. But then I need to find a space to put the thing in storage, which in turn means that I have to remove something else. A good candidate is some Commodore PC which I once got in a deal together with a PET 8296-D, but which I never really wanted. Also, some bulk computer printout piles can be pruned. Of course, every time I look in those things, I come across interesting stuff that I want to keep...


Sep. 8th, 2011 09:50 pm
rhialto: Me under a waterfall (Default)
I was sitting on my sofa, watching tv (on the computer), and I felt my sofa move forward and backward... hmmm... it is not supposed to do that sort of thing. So I thought, is this an earthquake? And so it was, I wasn't the only one who felt it.
The epicentre was about 21 km south of here, and the magnitude was apparently 4,4.
Quote: " meldt: epicentrum op 51.66 N, 5.95 O, 2 km diep, 21 km S van nijmegen, 1 km O van boxmeer magn 4,4"

Edit: the epicentre has been revised by EMSC to being closer now:  51.76 N ; 5.95 E, depth 10 km, "11 km SE Nijmegen (pop 158,732 ; local time 21:02:48.0 2011-09-08) 4 km S Groesbeek (pop 18,741 ; local time 21:02:48.0 2011-09-08)"

rhialto: Me under a waterfall (Default)
BiCon was pretty good. Danced with cute people, was a bit flirty with someone, and discovered someone who was at the famous Edinburgh soc.bi party in 1991, and had not seen since. I gave people my card - hopefully they'll also want to stay in touch. Of course there was too little time to chat with all the people I would have wanted to, as usual. It takes me a while to get going in that department, and before you know it, BiCon is over already.
Afterwards, I went to London to Isabelle's (lj:babounet) house, to visit the lodgers. I was hoping to meet other friends of Isabelle's too but that didn't work out. But the lodgers made me very welcome and made me nice food. They had made small but nice improvements to the house. Isabelle's room is in use as a tv room, but her things are still there, it is just rearranged a bit or put away in cupboards. For me that was actually good - it was a lot less triggery that way. (Also it was good that the BiCon venue wasn't exactly the same as when I was there with Isabelle, for the same reason. That is also a reason I booked en-suite accommodation rather than standard, like we had then.) I did randomly rummage through her things, which was rather triggering, but I am glad I still can do at least that.
I also visited Foyle's and bought some books - only two, since it had to fit within my hand baggage mass limit. Since there are lots of building works around the Tottenham Court Road underground station (the one nearest to Foyle's) I walked to Oxford Circus (instead of Goodge Street, I used on the way out), and I was amazed by how incredibly busy it was. Big throngs of people moving into the entrance and through the ticket barriers, and eventually into trains (although I had to let the first one go since it was too full).
Still haven't visited Mornington Crescent.

Back home, they're going to replace my windows tomorrow morning very early, so I need to remove everything that is close to them. This is a lot of work, given the amount of stuff I have. But it looks it'll work out. Hopefully it won't rain to much.

Next month I will visit Isabelle's parents. I'm the only thing they have left of their only daughter, so this is rather important, especially for her mother. I hope it won't be too stressful for me. Fortunately, Rémy will be there too, to help with translations.

(edited 1 time)
rhialto: Me with a bi-triangle (biangle)
Like everybody else: if you wanted to say something to me after BiCon, non-publicly and/or anonymously, here is your chance. Comments are screened and will remain so (more so apparently on the Dreamwidth version of this post - LiveJournal unscreens comments when you reply to them so in that case they may be visible briefly).
rhialto: Me under a waterfall (Default)
 BiCon is over, and I had 3 stickers on my name badge for flirt blindness. Just to make it clear.

Recently I read somewhere that if you're blind (in the conventional sense), that your brain makes up for the lack of incoming signals by just making up some random stuff. A similar thing is exploited by things like the "brain machine" - flashing lights in front of your eyes plus rhythmic sounds. It makes you see pretty moving patterns in various colours, which are certainly not real.

I connected this with flirt blindness. If you never see when somebody is flirting with you, apparently your brain tries to see flirting in "random other stuff". Hence, you may think that somebody is flirting with you, even when they aren't. Which is exactly my experience, but I just hadn't connected the different types of blindness yet.

Doctor Who

Aug. 29th, 2011 12:28 am
rhialto: Me under a waterfall (Default)
With the second part of the Doctor Who series just started, it looks like we'll need to have a special Doctor Who viewing break at BiCon...
rhialto: Me under a waterfall (Default)
Stupid insensitive clods...

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("Would you change anything about your significant other? What would it be?")

I'd have her be not dead. Duh.
rhialto: Me under a waterfall (Default)
Yay! Yesterday I ordered train tickets to travel to CCC Camp 2011! Of course I ordered them from the German train website, not the Dutch one, because the latter is completely unusable and the former is actually decent and usable. It even comes in many languages, but I only actually discovered that right now, so I used it in German. I can read German well enough but I usually don't speak or write it, since I fear the result will not be very grammatical...
I just have to wait a few days for them to arrive in the post. If you get electronic ones, they're not transferable, and you need to show the conductor some ID.


May. 15th, 2011 03:06 pm
rhialto: Me under a waterfall (Default)
EuroBSDcon takes place in the Netherlands this year, in Maarssen (near Utrecht), 6-9 October. I suppose I should take the opportunity of going there, now it is held so nearby.
(The Call For Proposals is still open until the end of the month; sponsors are also still being sought)
For those who wonder: DragonFlyBSD is a project forked from FreeBSD by Matt Dillon, who was a very active Amiga developer in the same period that I was. I always was a big fan of his programs and I used Dme (an editor), Dasm (a 8-bit cross-assembler), Dnet (a networking package for multiple login and file transfers over the same modem link), DICE (Dillon's Integrated C Environment), Dmouse (a mouse blanker/accelerator), and probably some more that I'm forgetting, with great success.
rhialto: Me under a waterfall (Default)
Hello Sweetie Pea, it is your birthday today. I'm thinking of you, every day, and I miss you so, so much. I have been thinking that I understand now how attractive it is to believe in an afterlife. I almost wished I believed in an afterlife... but I don't. And I know you didn't either. So we'll have to rely on time travel. And that by then, after so many miracle announcements that turned out to be extremely early research findings, they finally found a cure for cancer.
Not so long after you passed away, the company that indirectly paid for my job went bankrupt, and it was uncertain if and how long I would keep my job. That whole thing was totally unimportant to me. I just noticed that the previous time I unwillingly lost a girlfriend (albeit not quite so finally), I also lost my job not long after. But now, after the dust has settled, I'll have my job until the time my contract expires normally (in August).
Your last wish for me was to go and do something nice. I've tried, and partially succeeded. I have fallen back a lot on familiar things though. I've been in touch with Teresa, my Portuguese ex, and visited her twice. And I'm in touch with my local ex Yvonne, who is unfortunately in psychiatric care. I visit her every week for an hour.
I don't feel I'm up to having another relationship yet, even though I know you'd encourage it.
Your parents phone me every now and then. My French still isn't very good, so it is a bit of a one-sided conversation. But I guess they just want to hear my voice. They say they consider me their son, which is a great honour (and a bit of a burden). They sent me an expensive-looking watch for christmas, and I sent them a dvd-transcription of the video tape that was made of that practice therapy session. You don't speak very much on it, and you don't move much either, so as a film it is really boring, but it is a bit of you. For some reason, I find it very hard to recall how your voice sounded. I don't understand that, I would like to hear you speak in my memories.
I also occasionally email with Satchel, who has moved back into your house again. I like him; it is good to have trusted people there.
Take care, my sweetie pea, and may you adopt many more Minous.
rhialto: Me under a waterfall (Default)
Today I bought an ebook reader from the HEMA which is actually the Ambiance Digibook ADB-106 (suddenly called MDB-106 when you look it up now; last week I just googled for "Ambiance Digibook" which is visible in the illustration on the printed flyer) which is actually the OAXIS EB-601.
It was on sale for only EUR 99. Page turning is a bit slow, and when you resize the font, it just scales the page and you have to select some other menu item to actually reflow the text.
Anyway, it professes to run Linux. The software information page even gives a list of various GPL programs that it uses with links to their home pages.
However, this seems insufficient to comply with the GPL.
I see at least the following deficiencies:
  1. The full text of the GPL is not included (GPL clause 1), just mentioned (not even by URL).
  2. Although general links (to project homepages) are provided, the exact source version that was used for the delivered product must be delivered (clause 3a or 3b; 3c does not apply as an option for commercial distribution).
  3. Missing is also "any associated interface definition files, plus the scripts used to control compilation and installation of the executable" (clause 3)
  4. There is also no tool chain included (this interpretation reads "scripts" to include cross-compilers and the like too).
The site of gpl-violations.org seems to be a bit un-updated the last 2 years. So where can I report this sort of thing, if HEMA is not quickly fixing their copyright violations?
rhialto: Me under a waterfall (Default)
In the same vein as my previous posting, I just read about a PDP-11 realised in FPGA:

It's about time NetBSD gets the PDP11 port done: the PDP-11/70 CPU core is now available as implementation on a FPGA-board, and there's need for a newer operating system than 2.11BSD! Citing from the homepage: ``The project contains a complete PDP-11 system: a 11/70 CPU with memory management unit, but without floating point unit, a basic set of UNIBUS peripherals (DL11, LP11, PC11, RK11/RK05), and last but not least a cache and memory controllers for SRAM and PSRAM. The design is FPGA proven, runs currently on Digilent S3BOARD and NEXYS2 boards and boots 5th Edition UNIX and 2.11BSD UNIX. ''

(from Hubert Feyrer's NetBSD blog)

Of course we should not forget about Jeri Ellsworth's Commodore One, the Commodore 64 in FPGA (and it is reconfigurable into other computers as well), or the MiniMig and its relatives and successors, Amigas in FPGA. Each of the the two seem to have evolved to allow the other configuration on its hardware. Information and discussion about these implementations seems a bit spread out over tons of different fora, since it has inspired many people to start similar projects. A generic "can-run-anything" FPGA board system would be nice...
rhialto: Me under a waterfall (Default)
In case you haven't noticed, some brilliant guys have analyzed the 6502. From
microscopic images of the chip they built a netlist and a simulator to actually
run the chip, from this netlist!


This allows to actually analyze all the peculiarities, for example why an
interrupt during a taken branch is delayed by an instruction.
http://forum.6502.org/viewtopic.php?t=1634 - might be worth looking into that
for the Commodore emulators...

(from the cbm-hackers mailinglist)