5 ms·

The Ultimate Commodore 1541 Disk Drive Talk [video]

96 points by Audiophilip 5y ago

allenu 5y ago
Looking forward to watching this. His previous talks, such as the Ultimate Commodore 64 Talk, have been comprehensive, clear, while being very concise on each bit of info.
- rzzzt 5y ago
  Does a high quality version of the Ultimate C64 Talk exist somewhere? I only see fairly low bitrate versions of it. (The embed on Michael's website is dancing postage stamp-sized.)
  - Audiophilip 5y ago
    I'm not sure there is one. There are some mirrors[0] that have a copy of the original recording[1], but apparently still very low-res. [0]: https://events.ccc.de/congress/2008/wiki/Conference_Recordings/index.html https://events.ccc.de/congress/2008/wiki/Conference_Recordin... [1]: http://ftp-stud.hs-esslingen.de/Mirrors/CCC/25C3/video_h264_720x576/25c3-2874-en-the_ultimate_commodore_64_talk.mp4 http://ftp-stud.hs-esslingen.de/Mirrors/CCC/25C3/video_h264_...
  - anyfoo 5y ago
    Not exactly what you're asking for, but https://www.youtube.com/watch?v=ZsRRCnque2E https://www.youtube.com/watch?v=ZsRRCnque2E while being 480p and rather noisy, was very sufficient for me to watch and enjoy the talk back in the day. The presented material does not suffer much on the relatively low resolution.
- anyfoo 5y ago
  I'm only 20 minutes in, but I can already tell you that you won't be disappointed. I feel like after just about a third of the video I already fully understand the physical and logical disk format. Like the previous videos, it's chock full of dense information presented with very clear visualization.
gfaure 5y ago
I was lucky enough to see this talk in person at the Vintage Computer Festival West this year. One of the absolute highlights (timestamp https://youtu.be/_1jXExwse08?t=1903 https://youtu.be/_1jXExwse08?t=1903) was the incredible work on a custom disk loader that increased the throughput from 400 bytes/s to 7.5 kB/s! A writeup of that optimisation work, which was only published in 2013, can be found here: https://www.linusakesson.net/programming/gcr-decoding/index.php https://www.linusakesson.net/programming/gcr-decoding/index....
- crispyambulance 5y ago
  The same person also wrote "The TTY Demystified" also a very good read: https://www.linusakesson.net/programming/tty/index.php https://www.linusakesson.net/programming/tty/index.php
- buescher 5y ago
  "In order to shave off a cycle from every instruction that modifies another one, the entire loop will be placed in the zero-page." Oh wow.
  - TacticalCoder 5y ago
    If you like that kind of stuff, here's the 256 bytes (!) C64 intro "A mind is born" and its technical explanation... It's using that same zero-page trick: https://linusakesson.net/scene/a-mind-is-born https://linusakesson.net/scene/a-mind-is-born I have no words... These coders are amazing!
- c64d81744074dfa 5y ago
  > increased the throughput from 400 bytes/s to 7.5 kB/s Since then someone has come up with yet another custom disk loader that's more than twice as fast as that one! https://csdb.dk/release/?id=197710 https://csdb.dk/release/?id=197710 It's incredible that people are still pushing the limits of the stock C64 system these days...
  - TMWNN 5y ago
localhost 5y ago
I wrote one of the early fastload cartridges for the 1541 (Epyx had the famous one, but mine also did a fast format, and drive to drive backup across two 1541s) and am looking forward to going down memory lane with this talk! Thanks for the share!
- fatnoah 5y ago
  I had the Epyx one, but I never realized there were others.
  - localhost 5y ago
    Mine was the GT4 cartridge, distributed by Pro-Line Software, the same folks who distributed WordPro 64, WordPro for the Vic-20 which I did the port for and likely some versions for the PET as well though that was probably Pro-Micro software IIRC.
comeonseriously 5y ago
I remember, as a kid, playing copy protected games at night and hoping my dad didn't wake up mad at me because of all the CLACK CLACK CLACK CLACKing that the drive head was doing as the protection scheme was slamming it all the way to one side to read some bit of data. Good times, man.
mrlonglong 5y ago
I was astonished to learn that it takes another 6502 to power the 1541 drive. Kinda neat if you think about it, and I believe someone has succeeded in using it as a 2nd processor, much like the famed 6502 coprocessor tube on the Acorn machines. Those days were great.

96 points by Audiophilip 5y ago

Looking forward to watching this. His previous talks, such as the Ultimate Commodore 64 Talk, have been comprehensive, clear, while being very concise on each bit of info.

rzzzt 5y ago
Does a high quality version of the Ultimate C64 Talk exist somewhere? I only see fairly low bitrate versions of it. (The embed on Michael's website is dancing postage stamp-sized.)
- Audiophilip 5y ago
  I'm not sure there is one. There are some mirrors[0] that have a copy of the original recording[1], but apparently still very low-res. [0]: https://events.ccc.de/congress/2008/wiki/Conference_Recordings/index.html https://events.ccc.de/congress/2008/wiki/Conference_Recordin... [1]: http://ftp-stud.hs-esslingen.de/Mirrors/CCC/25C3/video_h264_720x576/25c3-2874-en-the_ultimate_commodore_64_talk.mp4 http://ftp-stud.hs-esslingen.de/Mirrors/CCC/25C3/video_h264_...
- anyfoo 5y ago
  Not exactly what you're asking for, but https://www.youtube.com/watch?v=ZsRRCnque2E https://www.youtube.com/watch?v=ZsRRCnque2E while being 480p and rather noisy, was very sufficient for me to watch and enjoy the talk back in the day. The presented material does not suffer much on the relatively low resolution.
anyfoo 5y ago
I'm only 20 minutes in, but I can already tell you that you won't be disappointed. I feel like after just about a third of the video I already fully understand the physical and logical disk format. Like the previous videos, it's chock full of dense information presented with very clear visualization.

gfaure 5y ago

I was lucky enough to see this talk in person at the Vintage Computer Festival West this year. One of the absolute highlights (timestamp https://youtu.be/_1jXExwse08?t=1903 https://youtu.be/_1jXExwse08?t=1903) was the incredible work on a custom disk loader that increased the throughput from 400 bytes/s to 7.5 kB/s! A writeup of that optimisation work, which was only published in 2013, can be found here: https://www.linusakesson.net/programming/gcr-decoding/index.php https://www.linusakesson.net/programming/gcr-decoding/index....

crispyambulance 5y ago
The same person also wrote "The TTY Demystified" also a very good read: https://www.linusakesson.net/programming/tty/index.php https://www.linusakesson.net/programming/tty/index.php
buescher 5y ago
"In order to shave off a cycle from every instruction that modifies another one, the entire loop will be placed in the zero-page." Oh wow.
- TacticalCoder 5y ago
  If you like that kind of stuff, here's the 256 bytes (!) C64 intro "A mind is born" and its technical explanation... It's using that same zero-page trick: https://linusakesson.net/scene/a-mind-is-born https://linusakesson.net/scene/a-mind-is-born I have no words... These coders are amazing!
c64d81744074dfa 5y ago
> increased the throughput from 400 bytes/s to 7.5 kB/s Since then someone has come up with yet another custom disk loader that's more than twice as fast as that one! https://csdb.dk/release/?id=197710 https://csdb.dk/release/?id=197710 It's incredible that people are still pushing the limits of the stock C64 system these days...
- TMWNN 5y ago

localhost 5y ago

I wrote one of the early fastload cartridges for the 1541 (Epyx had the famous one, but mine also did a fast format, and drive to drive backup across two 1541s) and am looking forward to going down memory lane with this talk! Thanks for the share!

fatnoah 5y ago
I had the Epyx one, but I never realized there were others.
- localhost 5y ago
  Mine was the GT4 cartridge, distributed by Pro-Line Software, the same folks who distributed WordPro 64, WordPro for the Vic-20 which I did the port for and likely some versions for the PET as well though that was probably Pro-Micro software IIRC.

comeonseriously 5y ago

I remember, as a kid, playing copy protected games at night and hoping my dad didn't wake up mad at me because of all the CLACK CLACK CLACK CLACKing that the drive head was doing as the protection scheme was slamming it all the way to one side to read some bit of data. Good times, man.

mrlonglong 5y ago

I was astonished to learn that it takes another 6502 to power the 1541 drive. Kinda neat if you think about it, and I believe someone has succeeded in using it as a 2nd processor, much like the famed 6502 coprocessor tube on the Acorn machines. Those days were great.