+mizapf Posted February 27, 2014 Share Posted February 27, 2014 MESS and TIImageTool have been supporting this PC99 format for some time now, but as I learned there is a little glitch in there, concerning the single-sided formats, and while I'm working on the floppy modernization, I guess this is a good time to fix that. Is it correct that PC99 stores single-sided formats into the same image files as double-sided ones, just leaving the second half uninitialized? This would mean we have only two valid sizes: - FM recording (single density): 260240 bytes - MFM recording (double density): 549760 bytes each one for both single sided and double sided images. Are there any other known formats for track images? (80 tracks? 36 sectors?) 1 Quote Link to comment Share on other sites More sharing options...
matthew180 Posted March 5, 2014 Share Posted March 5, 2014 Did you ever get any answers to this? I have to believe Fred Kaal would have a really good idea about this, but I don't think he lurks here. Maybe in the Y! group? Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 6, 2014 Author Share Posted March 6, 2014 I've got a reply from Ernest Pergrem via PM, confirming that there are only two PC99 formats around (single density and double density), each one used for both single and double-sided. I guess this should be found in the PC99 manual as well. Quote Link to comment Share on other sites More sharing options...
+hloberg Posted March 6, 2014 Share Posted March 6, 2014 Need a copy of the PC99 manual? Quote Link to comment Share on other sites More sharing options...
airernie Posted March 7, 2014 Share Posted March 7, 2014 Need a copy of the PC99 manual? I don't think that CaDD has publically released the manual, which means it can't be distributed to non-PC99 owners. Ernie Quote Link to comment Share on other sites More sharing options...
+hloberg Posted March 7, 2014 Share Posted March 7, 2014 I don't think that CaDD has publically released the manual, which means it can't be distributed to non-PC99 owners. Ernie Actually, they posted the manual online. http://www.cadd99.com/pc99doc.pdf Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 7, 2014 Author Share Posted March 7, 2014 OK, on page 70 the manual says that there are only two sizes: 260240 or 549760, which depends on the emulated controller (1771 or 1772) that is used in PC99; single-sided formats use the same file size as the corresponding double-sided format. I suppose only the first half of the file is used, and the second half is either zeros or simply ignored; I did not see anything about that in the text. Quote Link to comment Share on other sites More sharing options...
+acadiel Posted March 7, 2014 Share Posted March 7, 2014 So if SSSD = 90K, DSSD = 180K, then what is the extra 80K used for in the smaller size? The same if you have a DSDD 360K, you then have an extra 190K. Just wondering :-) Quote Link to comment Share on other sites More sharing options...
Gazoo Posted March 7, 2014 Share Posted March 7, 2014 So if SSSD = 90K, DSSD = 180K, then what is the extra 80K used for in the smaller size? The same if you have a DSDD 360K, you then have an extra 190K. Just wondering :-) The bytes between the sectors. Quote Link to comment Share on other sites More sharing options...
airernie Posted March 8, 2014 Share Posted March 8, 2014 Actually, they posted the manual online. http://www.cadd99.com/pc99doc.pdf Your are correct.. My bad. Quote Link to comment Share on other sites More sharing options...
+mizapf Posted March 8, 2014 Author Share Posted March 8, 2014 The bytes between the sectors. No, this would account for the difference between the track size of 3253 bytes for single density compared to 9*256 = 2304 bytes. I'd say the extra 90K that acadiel is wondering about are simply unused, similar to a floppy disk that is recorded on one side only. By the way, I found that the tracks of the PC99 format (which is used for the TDF in MESS) are somewhat too long. This became apparent when I was working to adapt the TI floppy emulation in MESS to the new core floppy system and tried to put one such track into an emulated floppy track. Simple calculation: We have 300 rpm, which means that reading a complete track takes 0.2 seconds. The cell sizes for FM recording are 4 µs, so we have 50000 cells on the track, and it takes 16 cells to encode 8 bits, so this means we get 3125 bytes at max per track. For MFM the cell sizes are 2 µs, which means 6250 bytes. PC99 defined 3253 bytes (FM) and 6872 bytes (MFM). My guess is that the track sizes are a result of reading a track with the "read track" function of the disk controller, which is known to deliver trailing bytes for some time after the track is finished (until it "interrupts out" (spec of WD177x)). Quote Link to comment Share on other sites More sharing options...
Romko343 Posted March 9, 2014 Share Posted March 9, 2014 Does anyone have link to download PC992V9T9.EXE - file makes PC99.dsk image to V9T9 or MESS format. Quote Link to comment Share on other sites More sharing options...
+Lee Stewart Posted March 9, 2014 Share Posted March 9, 2014 Does anyone have link to download PC992V9T9.EXE - file makes PC99.dsk image to V9T9 or MESS format. Fred Kaal's TI99DIR.exe can do that. His site is http://home.vodafonethuis.nl/fgkaal/. ...lee Quote Link to comment Share on other sites More sharing options...
Flottmann1 Posted March 9, 2014 Share Posted March 9, 2014 Does anyone have link to download PC992V9T9.EXE - file makes PC99.dsk image to V9T9 or MESS format. ftp://whtech.com/emulators/pc99/pc99utilities/ Quote Link to comment Share on other sites More sharing options...
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