| |
Burglar
Registered: Dec 2004
Posts: 1088 |
X2016 Competitions: Your Input Wanted!
The 28th of october is still far away but getting closer and closer. The organizers have been getting busy and are now well underway to get everything sorted out for another smashing X!
Since entry delivery and running the compos at X14 went quite smooth and voting is now done in realtime, we believe we may have room for 1 or 2 more (small/fun) c64 competitions. Like a PETSCII compo or a 4k compo, or maybe you guys have an idea?
Or perhaps you think the straightforward demo/music/gfx compos are enough.
Let us know :) |
|
... 214 posts hidden. Click here to view all posts....
|
| |
Bitbreaker
Registered: Oct 2002
Posts: 504 |
Well, it is also about: write the disk on a floppy that spins with 298rpm and read it in on a floppy that spins with 302rpm. The tight timing in the sector read loops and sector header reading might fail consequently and force the loader to hang for ever/until retry count is reached. This is also a problem one needs to cope in real hardware land.
That said, i'm still for real hw use and so far it was no problem to request this on the compo, i'd just be happy to have a dry run on the hw next time :-D The whimps can of course till cry for 1541u :-D Not to forget that loading on real hw has way more jitter in loading times and sync has to be laid out with more margins around the loading. |
| |
MagerValp
Registered: Dec 2001
Posts: 1074 |
Quoting BitbreakerFreezing for diskchange always bears the risk of crashes/fuckups when using NMIs, what we also dare to use in turn disk parts :-)
Freezing for disk change is never acceptable in a compo anyway, you need a two computer setup or standalone 1541U. |
| |
Mr.Ammo
Account closed
Registered: Oct 2002
Posts: 228 |
Quoting MagerValp
Freezing for disk change is never acceptable in a compo anyway, you need a two computer setup or standalone 1541U.
If Gideon will not deliver a stable 3.0 firmware with a configurable flip-the-disk button before X, we'll definitely consider using the spare compo machines as 'standalone' 1541Us next to bringing some more diskdrives. |
| |
chatGPZ
Registered: Dec 2001
Posts: 11359 |
Quote:Chameleon works very badly as external stand alone drive, it has serious timing problem on iec connector that makes some of the demos fail miserably.
thats a bit exaggerated - the timing difference to real drives is *less than one cycle* and no properly implemented loader will have a problem with it. in fact, its exactly one single loader that fails - you can easily see from socis list which one that is :o) (and this loader has problems on not-so-perfect real drives as well) |
| |
lft
Registered: Jul 2007
Posts: 369 |
Quoting sociI've just did a small research on the limited set of popular loaders I'm aware of.
...
Thanks for this breakdown! I wonder, when you state that a loader does checksums, are you referring to the serial transfer or just the process of reading a block from disk? Spindle does the checksumming on the C64 side, which captures both kinds of errors. |
| |
enthusi
Registered: May 2004
Posts: 677 |
just curious, is the serial transfer ever likely to fail? That being said, a load of tap was shown live from tape with badass monitors degaussing left and right... |
| |
soci
Registered: Sep 2003
Posts: 479 |
Only the GCR bitstream was randomly corrupted in the test. (~1 in 8000)
I assumed no-one would check the integrity between the drive and the c64, so I didn't even tried that.
I was wrong ;) This stuff is pretty advanced. |
| |
soci
Registered: Sep 2003
Posts: 479 |
The "usual" failure mode for serial transfers of fastloaders is when there's not enough safety margin for asynchronous transfers.
If the oscillators are a bit more detuned or the serial cable is longer sampling may happen around the transition and not when the signals are stable.
I think there's also some timing difference with the C128DCR's 1571 which makes this worse. At least I remember I had to adjust the timing for that in the past when I still determined it by trial-and-error. But cycle counting gives more reliable results. |
| |
ChristopherJam
Registered: Aug 2004
Posts: 1408 |
This just about calls for a new topic, but what sort of errors occur in the GCR stream in practice when using different drives?
Is it purely extra/missing zeros generated by gaps between polarity changes being too long/short, hence also throwing out the byte boundaries for the rest of the block? And how often does this tend to occur? |
| |
Grue
Registered: Dec 2001
Posts: 161 |
Quote: Quoting sociI've just did a small research on the limited set of popular loaders I'm aware of.
...
Thanks for this breakdown! I wonder, when you state that a loader does checksums, are you referring to the serial transfer or just the process of reading a block from disk? Spindle does the checksumming on the C64 side, which captures both kinds of errors.
Might be, but it does work with my 1541-II and 1541ultimate, but fails on Chameleon if using its external iec. |
| Previous - 1 | ... | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 - Next |
