ralphb Posted June 2, 2015 Share Posted June 2, 2015 When running some xdt99 cross-checks in Classic99 I noticed that the end-of-file byte marker for DIS/VAR files generated as FIAD files seems to be off by one. BASIC program: 10 OPEN #1:"DSK2.ONELINE",DISPLAY ,OUTPUT,VARIABLE 32 20 PRINT #1:"123456789" 30 CLOSE #1 Resulting FIAD file: 00000000 4f 4e 45 4c 49 4e 45 20 20 20 00 00 80 07 00 01 |ONELINE ......| 00000010 0b 20 01 00 00 00 00 00 00 00 00 00 00 00 00 00 |. ..............| 00000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| FDR on MESS disk image: 00: 4F 4E 45 4C 49 4E 45 20 20 20 00 00 80 07 00 01 ONEL INE .. .... 10: 0A 20 01 00 A9 79 1E C2 A9 79 1E C2 22 00 00 00 . .. .y.. .y.. "... 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .... .... .... .... The EOF byte is "0B" in the FIAD file but "0A" in the disk image. Is this a "feature" of FIAD files that the EOF marker is off by one? I currently cannot double-check what v9t9 does (but Win994a agrees with MESS). I also noticed that Classic99 has issues with EOF in Extended Basic. More specifically, it reads past EOF when using MESS disk images. ... 1000 IF EOF(1)THEN RETURN 1010 INPUT #1:L$ ... -> I/O ERROR 25 IN 1010 Could this be related? 1 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/ Share on other sites More sharing options...
+Lee Stewart Posted June 3, 2015 Share Posted June 3, 2015 ... but Win994a agrees with MESS ... ...as does PC99. ...lee Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3249915 Share on other sites More sharing options...
Tursi Posted June 3, 2015 Share Posted June 3, 2015 (edited) I'll compare against the TI DSR. Thanks! That said, VT9T9 is a deprecated format, and V9T9 is not a direct copy of the FDR from a disk image. Do TIFILES files have the same issue? Edited June 3, 2015 by Tursi Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250108 Share on other sites More sharing options...
+Lee Stewart Posted June 3, 2015 Share Posted June 3, 2015 ... Do TIFILES files have the same issue? My comparison was using FIAD with a TIFILES header, which showed an EOF byte of 11 compared to DSK images in MESS and PC99, which each had a value of 10. ...lee Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250130 Share on other sites More sharing options...
ralphb Posted June 4, 2015 Author Share Posted June 4, 2015 I'll compare against the TI DSR. Thanks! That said, VT9T9 is a deprecated format, and V9T9 is not a direct copy of the FDR from a disk image. I see, so TIFILES would be the preferred file format for Classic99? And I'm curious, Tursi -- did you create your own disk controller for Classic99, or do you create a sector map etc. in the emulator on the fly? Would a module like the original Disk Manager even work in Classic99? v9t9 file headers seem to be very similar to the FDR on disk, except for file timestamps. Do emulators use the local file timestamps instead? And how popular are v9t9-style files in general, i.e., in terms of emulators and/or working with real hardware? Oh, and FIAD == Files ON a disk? What's that about? BTW, here's another quick check to see that there's something off in Classic99: OPEN #1:"DSK1.FOO",DISPLAY,OUTPUT,VARIABLE 255 throws I/O Error 02, for both TIFILES and v9t9. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250758 Share on other sites More sharing options...
Opry99er Posted June 4, 2015 Share Posted June 4, 2015 I think it's Files IN a DISK. Tursi also has implemented the ability to insert a DOAD disk and run it from a drive. As far as sector access, he has done quite a bit there, but he will have to give all the details. The TI FDC is implemented, but not default. You can switch to it. For my purposes, FIAD format with the Classic99 default custom FDC is just fine. I can use mizapf's Image tool or TI99Dir to convert to DOAD if need be. Don't know if any of that helped. 1 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250764 Share on other sites More sharing options...
+Lee Stewart Posted June 4, 2015 Share Posted June 4, 2015 ... Oh, and FIAD == Files ON a disk? What's that about? ... “FIAD” means “Files In A Directory”—each TI file is in a directory on the PC. ... BTW, here's another quick check to see that there's something off in Classic99: OPEN #1:"DSK1.FOO",DISPLAY,OUTPUT,VARIABLE 255 throws I/O Error 02, for both TIFILES and v9t9. This is not “something off in Classic99”! There is no such animal as DV255. DV254 is the maximum. Variable records have a preceding length byte and 0xFF as the sector-termination byte. ...lee Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250800 Share on other sites More sharing options...
Willsy Posted June 4, 2015 Share Posted June 4, 2015 FIAD=files in a directory. IIRC Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250803 Share on other sites More sharing options...
+Lee Stewart Posted June 4, 2015 Share Posted June 4, 2015 (edited) I think it's Files IN a DISK. Tursi also has implemented the ability to insert a DOAD disk and run it from a drive. As far as sector access, he has done quite a bit there, but he will have to give all the details. ... See my last post for meaning of “FIAD”. “DOAD” means “Dump Of Disk On A Disk”, which is a dump of a TI disk to a disk image file. DOAD’s usually have a DSK extension. ...lee Edited June 5, 2015 by Lee Stewart Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250810 Share on other sites More sharing options...
ralphb Posted June 4, 2015 Author Share Posted June 4, 2015 This is not “something off in Classic99”! There is no such animal as DV255. DV254 is the maximum. Variable records have a preceding length byte and 0xFF as the sector-termination byte. IIRC the >FF is dropped if the the sector is filled completely, with the EOF marker being 0, so DV255 works just fine. At least that's the behavior I observe in MESS, where the statement works just fine. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250843 Share on other sites More sharing options...
ralphb Posted June 4, 2015 Author Share Posted June 4, 2015 See my last post for meaning of “FIAD”. “DOAD” means “Dump Of A Disk”. DOAD’s usually have a DSK extension. ...lee OK, thanks to all for the clarification! Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250844 Share on other sites More sharing options...
+Lee Stewart Posted June 4, 2015 Share Posted June 4, 2015 IIRC the >FF is dropped if the the sector is filled completely, with the EOF marker being 0, so DV255 works just fine. At least that's the behavior I observe in MESS, where the statement works just fine. Not according to the TI docs. And it does not work in MESS for me. It gives the I/O error 02 . ...lee Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250851 Share on other sites More sharing options...
ralphb Posted June 4, 2015 Author Share Posted June 4, 2015 Ah, interesting, it definitely works for me ... but as it turns out I'm using the Myarc HFDC controller in MESS. When I switch to the TI disk controller then the statement also fails for me! So never mind my suggestion that this could somehow be related to the EOF marker. 1 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250862 Share on other sites More sharing options...
+mizapf Posted June 4, 2015 Share Posted June 4, 2015 I just wanted to add ... but now it seems this has already been proved ... on this level it's very likely the DSR author who is to blame. MESS itself does not have any code inside that can control how the contents of a disk or file look like. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250867 Share on other sites More sharing options...
+InsaneMultitasker Posted June 4, 2015 Share Posted June 4, 2015 Ah, interesting, it definitely works for me ... but as it turns out I'm using the Myarc HFDC controller in MESS. When I switch to the TI disk controller then the statement also fails for me! So never mind my suggestion that this could somehow be related to the EOF marker. Which statement fails? Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250905 Share on other sites More sharing options...
ralphb Posted June 4, 2015 Author Share Posted June 4, 2015 Which statement fails? OPEN #1:"DSK1.FOO",DISPLAY,OUTPUT,VARIABLE 255 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250943 Share on other sites More sharing options...
+arcadeshopper Posted June 4, 2015 Share Posted June 4, 2015 I'll compare against the TI DSR. Thanks! That said, VT9T9 is a deprecated format, and V9T9 is not a direct copy of the FDR from a disk image. Do TIFILES files have the same issue? note: when using hdx server and sharing a directory with real ti's and classic99 v9t9 format is required Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3250951 Share on other sites More sharing options...
+InsaneMultitasker Posted June 4, 2015 Share Posted June 4, 2015 OPEN #1:"DSK1.FOO",DISPLAY,OUTPUT,VARIABLE 255 Lee is correct - this should fail. However, I did confirm that with the Geneve such a file can be opened. I did not test with the HFDC directly. I suspect this is a bug related to the effort to expand the record size beyond 255 bytes. The HFDC and Geneve DSR sources both reference "extended record length" and the HFDC manual defines the use of a corresponding 2-byte value. I suspect it never came to fruition due to multiple programs not knowing how to deal with a 2-byte record length, especially disk managers and file transfer routines relying upon level 2 IO. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251022 Share on other sites More sharing options...
Tursi Posted June 5, 2015 Share Posted June 5, 2015 note: when using hdx server and sharing a directory with real ti's and classic99 v9t9 format is required V9T9 is not a suitable format for modern file systems. I will not change my stance on it. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251109 Share on other sites More sharing options...
Tursi Posted June 5, 2015 Share Posted June 5, 2015 (edited) (nevermind, this was probably about something else) Edited June 5, 2015 by Tursi Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251111 Share on other sites More sharing options...
Tursi Posted June 5, 2015 Share Posted June 5, 2015 See my last post for meaning of “FIAD”. “DOAD” means “Dump Of A Disk”. DOAD’s usually have a DSK extension. ...lee From the original V9T9 documentation, where the terms were defined: If you use the emulated disk ROM provided with V9t9, you can use "files-in-a-directory" or FIAD emulation. If you use the disk ROM from the actual 99/4A disk controller, you can use "disk- on-a-disk" or DOAD emulation. If you use both ROMs, you can use both FIAD and DOAD at the same time. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251112 Share on other sites More sharing options...
Tursi Posted June 5, 2015 Share Posted June 5, 2015 I see, so TIFILES would be the preferred file format for Classic99? Yes, because it is a classic format allowing direct interchange with a real TI-99. In the 80's, this was the format used to store TI files on a foreign disk system. And I'm curious, Tursi -- did you create your own disk controller for Classic99, or do you create a sector map etc. in the emulator on the fly? Yes, it's all from scratch (except the beta-only TI disk controller emulation which you have to manually switch on). Would a module like the original Disk Manager even work in Classic99? Within limits. Directories will work on any system. Sector access beyond the catalog sectors will only work on disk images. The DSR does not support renaming or deleting files, or formatting disks, on purpose. New blank disks can be created in the Classic99 menu, or with any number of external utilities. Renaming and deleting files can be done in the Windows UI much more simply (except for V9T9 files, who embed the filename, which is the main reason I don't like them). Again, the TI Disk Controller doesn't work with files, but sectors (from the emulator's point of view), so doesn't enforce those limits, although I haven't implemented the format command there. v9t9 file headers seem to be very similar to the FDR on disk, except for file timestamps. Do emulators use the local file timestamps instead? And how popular are v9t9-style files in general, i.e., in terms of emulators and/or working with real hardware? They are intended to be very similar. Real TI disk controllers (with specific system exceptions) don't have timestamps - that's an extension to the format in all cases. I'm not going to talk to popularity. Oh, and FIAD == Files ON a disk? What's that about? Just me forgetting the acronym, see previous message. Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251114 Share on other sites More sharing options...
+Lee Stewart Posted June 5, 2015 Share Posted June 5, 2015 From the original V9T9 documentation, where the terms were defined: If you use the emulated disk ROM provided with V9t9, you can use "files-in-a-directory" or FIAD emulation. If you use the disk ROM from the actual 99/4A disk controller, you can use "disk- on-a-disk" or DOAD emulation. If you use both ROMs, you can use both FIAD and DOAD at the same time. I stand corrected. I couldn't find the reference, so synthesized it from Thierry's definition, which said a DOAD was a sector dump of a TI disk, which is true, but not the source of the acronym. ...lee 1 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3251119 Share on other sites More sharing options...
Tursi Posted June 13, 2015 Share Posted June 13, 2015 Tracked down and fixed the off-by-one in the FIAD headers (was a case of knowing the right answer and even having it in the comments, but then coding it backwards ). Also found and fixed the EOF issue (was checking the wrong variable, probably been in there for a long time). Will be in the next release. 9 Quote Link to comment https://forums.atariage.com/topic/239006-classic99-fiad-files-eof-marker-off-by-one/#findComment-3257070 Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.