The guy helping to facilitate major discoveries?
Maybe he learned some keyboard shortcuts, turned to the camera and thought to himself "Now I'm really going to get stuff done, guys."
LisaList2
- May 19, 2024, 11:43:44 am
- Welcome, Guest
News:
2022.06.03 added links to LisaList1 and LisaFAQ to the General Category
31
on: April 20, 2024, 11:18:40 am
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Started by ried - Last post by ried | ||
32
on: April 20, 2024, 02:14:10 am
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Started by ried - Last post by stepleton | ||
Looking at the video, I could've been fooled if you'd told me it was a slide projector and an audio cassette. That part where the guy turns his head to face the camera is memorable...
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33
on: April 19, 2024, 06:57:12 pm
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Started by ried - Last post by ried | ||
This was on a plain ol' VHS tape.
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34
on: April 19, 2024, 02:14:35 pm
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Started by ried - Last post by blusnowkitty | ||
Where'd you find a U-matic deck to play it on?
Cool video though - pay close attention to the Lisa in the final shot and hey, it's a prototype! (No Apple jewel on the back panel and no/hand written paper label on the PSU) |
35
on: April 17, 2024, 11:25:02 pm
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Started by ried - Last post by ried | ||
36
on: April 13, 2024, 05:45:19 pm
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Started by AlexTheCat123 - Last post by AlexTheCat123 | ||
Wow, thanks so much guys! It makes a lot more sense now!
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37
on: April 13, 2024, 04:05:35 pm
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Started by AlexTheCat123 - Last post by pablo_marx | ||
A rough translation of the decompression routine into JavaScript:
Code: [Select] const iconWidth = 48; I've included that and some compressed icons from the rev H boot sources here: https://codepen.io/pablo_marx/pen/zYXLNrO There'a a dropdown at the top to select the icon. That'll populate the text field with the bytes from the sources. Alternatively if I missed some icons in the sources, one should be able to paste the bytes into the text field. And any time the text field changes it should render the icon beneath the text field. And finally, one should be able to right click the icon and do Save Image As if they'd like to keep it. |
38
on: April 13, 2024, 01:56:19 am
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Started by AlexTheCat123 - Last post by sigma7 | ||
In the Lisa Hardware Manual, it says that expansion card icons can be stored in a compressed format if the MSB of the icon count byte is set. And it also states that "a special program is currently available to do the compression", but I'm guessing that program has probably been lost to time. Does anybody know how this compression algorithm works and how the compressed icons are stored? After compression, are all icons the same length in ROM or or does the length of the icon vary based on the efficiency of the compression on that particular icon? A snippet from Chuck Lukaszewski (author of MW+) says: Code: [Select] * the unpacking routine gets a byte of 8 flags */ In the "Apple Lisa Boot ROM Listing.pdf" the unpack routine DSPICON is at 0x35E2 In the source file "Lisa Graphics RM248.G.TEXT" : Code: [Select] ;--------------------------------------------------------------------- The #90 constants are screen size dependent ( # horizontal pixels / 8 ) so would be different in the 3A ROM, but this doesn't affect the compression algorithm, only the code that draws into the screenbuffer. I think the compression goes like this: Starting with the final bitmap... Step 1: Turn solid black blocks into zeros by using XOR to encode only the changes from row to row: Start at the bottom (last) row, XOR with the (second last) row above it, to obtain the last row of the uncompressed data, XOR that with the (third last) row of original data to obtain the second last row of uncompressed data. Repeat until you reach the top row which is copied verbatim to the uncompressed data. Step 2: Now the compression step will remove the zero bytes from the uncompressed data from step 1: prior to each run of Hence the compression effectiveness depends on the icon. If the icon is a checkerboard, the compression method actually increases the size because the flag bytes are added but there are no zero bytes to remove. If the icon is all white, all the data bytes are removed and only the flag bytes remain. I once had a suspicion that the Macintosh used a similar icon compression method, but I don't recall if that was confirmed or not. HTH, I apologize for my errors above, I hope they are easy to find. edit: I now see that the code is for a 48 bit wide icon, so the rows are 6 bytes and so only 6 flag bits are used per row edit2: it looks like the BEQ.S DONE branch in MLOOP might be to ... ummm changed my mind... |
39
on: April 12, 2024, 06:28:41 pm
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Started by AlexTheCat123 - Last post by AlexTheCat123 | ||
In the Lisa Hardware Manual, it says that expansion card icons can be stored in a compressed format if the MSB of the icon count byte is set. And it also states that "a special program is currently available to do the compression", but I'm guessing that program has probably been lost to time. Does anybody know how this compression algorithm works and how the compressed icons are stored? After compression, are all icons the same length in ROM or or does the length of the icon vary based on the efficiency of the compression on that particular icon?
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40
on: March 27, 2024, 05:30:50 am
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Started by ried - Last post by greniu | ||
I also join the above request. I'm also seeking for LisaList 1.0 image.
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