• Please review our updated Terms and Rules here

COS310/WPS278 floppy images?

The layout on an RX50 (at least for WPS) is very different. It took a fair amount of digging through the WPS source to figure out what's what.

The first thing to notice is that only 12 bits of every 16 is used in an RX50, while an RX01 uses all bits by dividing 256 12-bit words among 3 128-byte sectors (words 0-127 low-order 8 bits in one sector, words 128-255 low-order 8 bits in the next, and the the high-order 4 bits for all 256 words in the third sector. Interleave on RX50 is 2:1 with a track skew, RX01 is a 3:1 interleave with no skew.

I don't think that PUTR is capable of transferring between the two.

Index of /bits/DEC/pdp8/wps-8

bitsavers.trailing-edge.com

Figuring out WPS encoding was a little thorny, but Wang OIS was nastier.
 
good info, so i'm guessing unless someone images the cos310 rx50 distribution it's going to be an uphill battle to get this working? the only idea i have left is pulling the individual files from the rx01 dist and manually putting them on a blank rx50 but my gut feeling is that won't work either
 
I can try to add the functionality of recoding the px01 image into the px50 image according to the above algorithm (3 px01 sectors into one px50 sector plus interleaving), but I’m not sure that it will be easy to add such functionality in ImageUtilsX (it has a certain internal ideology for working with images and I still can’t imagine how to fit this algorithm into it), perhaps it will be easier to write a new program based on some functionality from ImageUtilsX. But again the question arises - to what extent will the recoded image have the correct file structure and how downloadable will it be?
 
Hunta said:
rx50 :)
Next try http://www.KpXX.Ru/FTP/SDf3w5t4
.r8x50 - with interleave.
.r8x50n - without
Click to expand...
thank you for that :) strangely getting a 404 on these:

Code: 
hush@datz:~ % wget http://www.kpxx.ru/FTP/SDf3w5t4/cos310-v8.0.r8x50
--2024-02-03 13:17:48--  http://www.kpxx.ru/FTP/SDf3w5t4/cos310-v8.0.r8x50
Resolving www.kpxx.ru (www.kpxx.ru)... 46.0.193.146, 80.234.32.193
Connecting to www.kpxx.ru (www.kpxx.ru)|46.0.193.146|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2024-02-03 13:17:48 ERROR 404: Not Found.
 
hush said:
thank you for that :) strangely getting a 404 on these:

Code: 
hush@datz:~ % wget http://www.kpxx.ru/FTP/SDf3w5t4/cos310-v8.0.r8x50
--2024-02-03 13:17:48--  http://www.kpxx.ru/FTP/SDf3w5t4/cos310-v8.0.r8x50
Resolving www.kpxx.ru (www.kpxx.ru)... 46.0.193.146, 80.234.32.193
Connecting to www.kpxx.ru (www.kpxx.ru)|46.0.193.146|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2024-02-03 13:17:48 ERROR 404: Not Found.
Click to expand...
No problem from here using current Firefox.
 
if it is not too much of an ask, i would certainly appreciate it as i've appreciated all the help up to this point :) i wish i could be more useful here myself! this is very low on my priority list and i am happy continuing to poke at os/278 for now though, so please don't go out of your way to get it done.
 
I don’t yet fully understand the interleaving schemes for rx01 and rx50.
I tried using the standard scheme for px50:

Code: 
       // blkNum for convert
       const int NSECT = 10;

       int track = (blkNum/NSECT);
       int i = (blkNum % NSECT) * 2;
       if (i >= NSECT) i++;
       int sector = (i + 2 * track) % NSECT;
       track++;

And the next one (if I understand correctly 3:1) for rx01
Code: 
       // blkNum for convert
       const int NSECT = 26;
       const int NTRACK = 77;

       int track = blkNum / NSECT;
       int i = (blkNum % NSECT) * 3;
       if (i >= NSECT) i++;
       int sector = i % NSECT;
       track++;
 
You must log in or register to reply here.
Back
Top