 Previous Messages |
Posted By
BSZ
on 2025-04-18
09:50:04
|  Re: Strange thing: Shade demo freezes on stock CPU machines
@Retroshire:
why is the demo running well on a replacement CPU machine with the same 4 devices
This is all guesswork on my part.  I suspect that the replacement CPU does not follow the timings of the original CPU when handling the port. And this feature "compensates" for the drive-side mismatch. And whether this is true?  1 |
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Posted By
Gaia
on 2025-04-17
19:46:49
| Re: Strange thing: Shade demo freezes on stock CPU machines
Well, this was meant as a completely new IRQ loader back in the day, a modified version of a 2-bit loader based on Marko Mäkelä's "prototype" (here it is I think: https://cadaver.github.io/rants/2bitload.html). It was tested on a few configs only and that could have been the problem, as apparently the timing of the bitbanging part turned out to be quite tight. It worked just fine on my own 1541-II and Oceanic drive and I guess Larry's own config as well (since he received the loader and used it). Several months elapsed between sending the last verion and the release of Shade, I was a bit surprised that in the end it was used. Perhaps it can be patched.... though it's for sure not too obvious (especially in the lack of the source code).1 |
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Posted By
Retroshire
on 2025-04-17
17:25:51
| Re: Strange thing: Shade demo freezes on stock CPU machines
@Gaia do you have any clue in this matter?
@BSZ what keeps me busy is this strange fact: why is the demo running well on a replacement CPU machine with the same 4 devices, while it fails on machines with stock CPU. |
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Posted By
BSZ
on 2025-04-17
15:35:26
| Re: Strange thing: Shade demo freezes on stock CPU machines
I remembered an idea I tried out today. @Retroshire: This will not solve your problem, but I will write it down.
In yesterday's test, one drive failed to work, freezes this demo. I replaced a component in this drive: the peripheral IC that controls the serial bus. The result: the demo runs flawlessly! But the original IC is not faulty either, I have not experienced any errors with other programs.  It is likely that different production batches may differ in certain parameters. The loader in this demo may be sensitive to these.
I think you should not find fault with your hardware, maybe the demo loader needs some fine tuning.1 |
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Posted By
Csabo
on 2025-04-17
12:59:15
| Re: Strange thing: Shade demo freezes on stock CPU machines
@Ati it's SID card only. Do you have one? (BTW, slightly off topic, and I mentioned it before: Larry asked me to write music for this demo, but didn't like what I came up with. That would have been TED only That track I wrote was eventually used in CD5.) |
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Posted By
Ati
on 2025-04-17
12:38:10
| Re: Strange thing: Shade demo freezes on stock CPU machines
Shade. I tried it too. The demo runs to the end, but NO sound for me. On a plus/4 with unopened warrianty label and 1541/2. I tried again on my good old plus/4 with “new8501” cpu replacement, and NO sound again. Hmmm.1 |
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Posted By
Luca
on 2025-04-17
10:45:57
 | Re: Strange thing: Shade demo freezes on stock CPU machines
I perfectly remember this habit of the demo, tested on a real Plus/4, but can't remember the specific environment where it works or doesn't.1 |
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Posted By
Csabo
on 2025-04-17
08:07:18
| Re: Strange thing: Shade demo freezes on stock CPU machines
Also tried with all four download versions (Plus/4 World; Zimmers, Otherside, Rulez), no difference.
Good job eliminating that as a factor. I was going to ask that, specifically to make sure that the D64 you have is correct. Trying all 4 is an overkill since you can verify that the files are binary exact with the the built-in FC command or something like WinMerge, but that's fine.
One more thing to add: Erich (RIP) mentioned Club Info 101 that he could not get Shade to run on his stock machine. So, that's another data point.
The fact that for you (Retroshire) it's switching the CPU that makes it work or not work, but for BSZ it's switching the drive that does that is indeed very strange. Probably stating the obvious, but the loader must be the problem.1 |
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Posted By
Retroshire
on 2025-04-17
07:58:09
| Re: Strange thing: Shade demo freezes on stock CPU machines
@gerliczer I tried. No change. |
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Posted By
gerliczer
on 2025-04-17
06:14:39
| Re: Strange thing: Shade demo freezes on stock CPU machines
I have experienced one similarly weird phenomenon once. My plus/4 couldn't run High Technology, IIRC, from my 1541-II if they were plugged into the same extension/distributor. But would work fine if the power supplies were plugged into different wall sockets. 1 |
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Posted By
Retroshire
on 2025-04-17
05:38:35
| Re: Strange thing: Shade demo freezes on stock CPU machines
Added another 1541 drive in my test range (pi1541, 2x1541, 1541-II).
Result: exactly the same:
The stock CPU machines all freeze at 'the man with the hat' with all four devices
The machine with FPGA CPU (Pjotr Bugaj) is consistently running the demo perfectly with all four devices.
Also tried with all four download versions (Plus/4 World; Zimmers, Otherside, Rulez), no difference. |
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Posted By
BSZ
on 2025-04-16
18:27:11
| Re: Strange thing: Shade demo freezes on stock CPU machines
Extremely strange. Tried it with a factory machine + factory drive, runs perfectly. However, with the "daily use" drive freezes (just before the hat part). Everything else is the same, I just replaced the drive (both 1541-II). Could the DOS ROM be different? This needs to be looked into further.
Edit: out of curiosity, I also tried it with a 1571, works fine with that too. I suspect that the ROM difference will not be the problem. Probably something is very much on the edge.1 |
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Posted By
Retroshire
on 2025-04-16
16:25:16
| Re: Strange thing: Shade demo freezes on stock CPU machines
tried a 1541, 1541-II and a Pi-zero1541 with three different serial cables...1 |
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Posted By
BSZ
on 2025-04-16
13:29:46
| Re: Strange thing: Shade demo freezes on stock CPU machines
If you can, try another 1541 drive, and/or another serial cable. I don't know exactly what loader that program uses, but can be sensitive to such things.1 |
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Posted By
Retroshire
on 2025-04-16
12:50:40
| Re: Strange thing: Shade demo freezes on stock CPU machines
fails = freezes
It happens at the moment of the 'sliding man with hat'. |
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Posted By
Csabo
on 2025-04-16
07:44:08
| Re: Strange thing: Shade demo freezes on stock CPU machines
This is interesting, and although I won't be able to help directly, I think you really need to detail/document the "fails" part.
Is it always at the same point in the demo? What happens exactly? Perhaps a photo or a video of it would even help. |
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Posted By
Retroshire
on 2025-04-16
05:13:00
| Strange thing: Shade demo freezes on stock CPU machines
Really strange: Shade demo freezes with stock CPU. I tested it on 5 machines, demo running from floppy on a 1541 drive:
C16+64, stock CPU > fails
C16+64, replacement FPGA CPU (Piotr Bugaj) > succeeds
C116+64, stock CPU > fails
Plus/4, stock CPU > fails
Plus/4, stock CPU > fails
The only machine running Shade perfectly is the C16+64 with FPGA CPU.
When I swap one of the stock CPU's with the FPGA CPU on one of the other 4 machines, then the Shade demo is also running perfect on that machine.
Also in Plus4emu, the Shade demo is running perfect.
Highly strange, while most of the time certain demo's get stuck with a replacement CPU. For example: the Metapharstic 80% demo runs well on the machines with a stock CPU en freezes with the FPGA CPU. |
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