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Post by nonefornow on Jul 21, 2014 15:22:43 GMT
I am really surpise at the fact that there are so few D71 available. A search on pokefinder.org shows 17 files and a search on CBM8but.com shows about 100.
I really like the C1571 drive. It is more durable than the 1541, less prone to misalignment, and the diskettes have double the space. So I am not sure as to why so few D71 files are available.
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Post by donno128 on Jul 21, 2014 22:10:06 GMT
Fewer people have 1571 drives. They are companions to the C128, the C64 will recognize them as 1541 drives, so 64 users have to enter in the drive commands so they are recognized as double sided, so they have way less built in user base. There are even fewer .d81 images in the wild and they are recognized by C64 as such but the drive was/is so expensive that the user base remained small. Still... here's a d71 of some IPAINT images and some viewers including a fairly cool one for 16kb unexpanded VDC memory that has a movable window to view the whole 640 by 400 picture. ipaintview.d71 (341.5 KB) |
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Post by hydrophilic on Jul 22, 2014 11:17:43 GMT
Well 1571 may have less alignment issues than 1541, but has way way way more head issues. Absolutely terrible design. I do like the MFM and fast-serial however. Of course more space is good too, but 2nd side unreliable in my experience because of stupid drive head. Thanks for iPaint. I went searching for more info... found some sites that have pictures posted. Nice. But I couldn't find any info on the file format... after searching and searching and searching... eventually Google lead me back to this site! Only thing I could determine was iPaint uses BASIC 8 format but also has color info interlaced... looking at the file header with hex/disk editor and it doesn't make any sense. Like on the sample disk, file sizes vary wildly, but I don't think they are compressed, right? I mean there was a seperate program iPort for compressing iPaint files (into GIF as I've read). Assuming they are not compressed, I don't see anything in the file header that would indicate size of image... But they should be compressed right? I mean aren't they 640x400 ? But very different file sizes. And if they are compressed, what is the compression scheme ? Or more importantly, decompression scheme? I just find it can of weird that iPaint seems to be such a well-known (well for C128) but I can't find any documentation on the file format. Makes it hard to use... Sorry, I'm going WAY off topic from 1571... but another thing when searching for iPaint info, is people kept saying it has appearant 65,536 colors. I'm guessing they think two colors in a cell (4 bits for one, 4 bits for another) and then double it for interlace = 4 * 2 * 2 = 16 bits = 65,536 colors ?? But that isn't how you count dithered colors at all! Without interlace you have 16 * (16+1) / 2 = 136 colors. If you dither those 136 colors with interlace, you get 136 * (136+1) / 2 = 9,316 colors. That's off by a factor of 7 from 65,536!! Hmmm, well I guess the hype sold more copies of the software  |
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Post by VDC 8x2 on Jul 22, 2014 12:59:02 GMT
The only compression I can think of is basic 8's rle compression. 1 to 127 run length with the high bit indicating skip or compress.
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Post by donno128 on Jul 23, 2014 18:54:24 GMT
Rick Kane, the author of I Paint, talked about IP having 5 levels of compression, said that was mostly because it was just as easy as two. The concern was the amount of time spent compressing and decompressing, hence the quicker lower levels of compression. Do not ask me how or what he did.I know nothing. Noth---ing!
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