| Author: | Keith Henrickson (guest: search) |
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| Date: | Wed, Feb 28th, 2007 @ 14:41 ( . ) |
Thanx! I guess I should have thought of that. |
 | Author: | Pete Rittwage (registered user: 558 posts ) |
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| Date: | Sat, Mar 03rd, 2007 @ 22:54 ( . ) |
As for how the drive read it- nothing fancy. If you poll the memory address the drive head puts the data into directly, you don't have to worry about sync. The sync marks are only for the drive to frame each byte properly. A good comparison is an analog record album. You can keep "picking up the needle and dropping it on the record" until you hear the part of the song you like. :) |
 | Author: | Nate (guest: search) |
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| Date: | Sun, Mar 04th, 2007 @ 14:28 ( . ) |
On 03/03/2007 @ 22:54, Pete Rittwage wrote :
: : A good comparison is an analog record album. You can keep "picking up the needle and dropping it on the record" until you hear the part of the song you like. :) : -- I'd say it's more like you pick up the needle and drop it on the record, then wait as the song loops to get to the part you want to hear. This is different from a record where it's one continuous "spiral" (although that's the same as a CD, DVD, etc.) On the C64, each track is a full circle so if you start from any part on the circle, you'll eventually see all of it. And bitwise, as you point out, the circle is identical no matter where you start. |
 | Author: | JimDrew (registered user: 23 posts ) |
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| Date: | Wed, Mar 07th, 2007 @ 09:58 ( . ) |
Since the object to duplicating protection is being able to determine the write spice(s), it is important to be able to read the track and shift the data to determine where the splice occurs. The only thing we are concerned about is this. With the EPYX stuff (perhaps others), the "weak bits" created by the write splice is actually checked as part of the protection. They expect this data to change and never be the same or it won't load. They use this point to start their data reads when loading/sending their data too. |
| Author: | Pete Rittwage (registered user: 558 posts ) |
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| Date: | Wed, Mar 14th, 2007 @ 23:08 ( . ) |
I've never been able to get the whole correct track cycle on those syncless Vorpal (EPYX) tracks. When I read them, I get half the data correct and half shifted, so it's losing framing on me. Did SC do anything special to read these tracks? I notice that it must be set to NON-CBM, AUTOGAP, GAP LENGTH 7. What did these options do? |