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Krill
Registered: Apr 2002
Posts: 2980 |
Release id #167152 : Krill's Loader, repository version 164
If no problems emerge (i know they will, but anyways)... I can explain a bit about the full on-the-fly GCR block read+decode+checksumming. |
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Sparta
Registered: Feb 2017
Posts: 49 |
Yes, you got it. Spartan stepping uses the transfer loop to pace half-track steps instead of a timer. :)
I respectfully disagree with your second point. The computer-side code does not need to know whether the currently transferred block is the final block of a track. Thus, code can be simplified. Fetching and transferring a block takes roughly 27000-29000 cycles depending on speed zones. Spartan stepping adds 17 cycles to this (72 vs. 72.06 bycles/block transfer). I do not think this causes a significant delay resulting in missing the next block. The total loss while loading a full 35-track disk is 664*17= 11288 cycles, spread out evenly. Shrydar stepping, on the other hand, adds 12*256*34=104448 cycles delay. The difference is about 10-fold.
After the on-the-fly GCR loop and the 72-cycles/byte transfer loop, Spartan stepping was the first thing that resulted in a significant speed improvement in my loader.
I can see your point in your third comment. Your code's complexity-to-tightness ratio is extremely high. :) |
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
shrydar here.
Yes, I have wondered about doing a half track step mid transfer too, but I think the pertinent performance metric is percentage time saved, which even at interleave of three is only 0.5% (3072 cycles every 600,000 - and that's assuming no errors, and either perfectly aligned tracks or out of order loading).
Either shrydar stepping or spartan stepping is a huge improvement over the old "wait until you're about to try and read the next block, then spend 60+ bycles on stepping and stabilisation" mind. The biggest win is almost certainly from allowing the head to settle during the transfer.
I'm still undecided about when to do the second step in Marmaload; my own loader development's been on hold while I've been distracted by crunchers and demo effects.
At this rate I suspect that'll remain the case until I've at least one production out the door using Krill's instead - we'll see :) |
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Krill
Registered: Apr 2002
Posts: 2980 |
Quoting SpartaI respectfully disagree with your second point. The computer-side code does not need to know whether the currently transferred block is the final block of a track. You're probably right there. But the first and third points alone seem to prohibit Spartan Stepping in my case. And yes, what Shrydar aka ChristopherJam said. :) |
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Sparta
Registered: Feb 2017
Posts: 49 |
Quoting ChristopherJamThe biggest win is almost certainly from allowing the head to settle during the transfer.
Agreed on this. In my loader Sparkle, which will never be as versatile as Krill's, I think I am going to settle (huh) with the best of both worlds. I.e. I will time the second half-track step in the transfer loop about 12 bycles after the first one to allow enough time for the head to settle. Call it the Spartan Shrydar Step. :))
P.S. I was aware of the mysterious Shrydar's identity. Google knows everything. :) |
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bubis
Account closed
Registered: Apr 2002
Posts: 19 |
Quote: Quoting ChristopherJamThe biggest win is almost certainly from allowing the head to settle during the transfer.
Agreed on this. In my loader Sparkle, which will never be as versatile as Krill's, I think I am going to settle (huh) with the best of both worlds. I.e. I will time the second half-track step in the transfer loop about 12 bycles after the first one to allow enough time for the head to settle. Call it the Spartan Shrydar Step. :))
P.S. I was aware of the mysterious Shrydar's identity. Google knows everything. :)
We just don't know who you are, my Hungarian fellow. :) |
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map
Registered: Feb 2002
Posts: 27 |
Quoting Groepazpython has the same problems, i think (is it a single exe requiring no install?) (the point is: right now "our" dev environment is completely freestanding requiring no msys or cygwin or any of that, and no installing either - breaking that is not an option :))
the problem with ca65 are at least nucrunch and tinycrunch, those will not build.
One possibility might here to use Pyinstaller with option --onefile to create an .exe from the .py.
https://pypi.org/project/PyInstaller/
Using the UPX packer you can minimize the filesize of the .exe. |
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Krill
Registered: Apr 2002
Posts: 2980 |
Quoting Groepazpython has the same problems, i think (is it a single exe requiring no install?) (the point is: right now "our" dev environment is completely freestanding requiring no msys or cygwin or any of that, and no installing either - breaking that is not an option :)) Apparently, this does seem to exist: http://winpython.github.io/ - "The easiest way to run Python [...] out of the box on any Windows PC, without installing anything!", "WinPython lives entirely in its own directory, without any OS installation" and similar claims. There's some small print, though, so YMMV*.
* "Your metrage may vary" in PAL-land. |
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Krill
Registered: Apr 2002
Posts: 2980 |
Quoting mapUsing the UPX packer you can minimize the filesize of the .exe. Expect lots of Windows users to bemoan that their assorted snake-oil protection suite puts it into quarantine. |
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
Perhaps 'someone' should port tc_encode (the tinycrunch encoder) to c64? :D
Also, it's worth noting that the build issues with nucrunch and tinycrunch under newer versions of ca65 were fixed some time ago now. |
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map
Registered: Feb 2002
Posts: 27 |
Quoting KrillQuoting mapUsing the UPX packer you can minimize the filesize of the .exe. Expect lots of Windows users to bemoan that their assorted snake-oil protection suite puts it into quarantine.
True, but UPX is completely optional here.
Another hint: in case the target is to run the Python script using wine - the wine project only recently added the required libraries for the latest Python3. Not all Linux Distros have updated their packages yet. |
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