>>> When DOS detects an unreliable floppy change line hardware, >>> it should use the floppy label / serial / similar to detect >>> changes in software ... >> >> How does DOS ever detect that any hardware is "unreliable"?? > > I do not know, but earlier in this thread, somebody said that > the numbering of FAT filesystem exists, among other reasons, > to help DOS detect floppy changes even if there is no change > line available. As you know, int 13.15 can even report that > a floppy has no change line at all. MS DOS might, on top of > that, have a list of BIOS versions with "weak" change lines?
I think this excerpt might be relevant; from Geoff Chappell's "DOS Internals", chapter 16 ("Low-Level Disk Support"), after the section heading "Floppy Disk Drives", on page 605: << As a normal part of its initialization, IO.SYS categorizes the available floppy disk drives. For this purpose, it relies on the BIOS to report the drive's capabilities. Int 13h function 08h (Get Drive Parameters) returns the maximum supported values for the cylinder, head and sector parameters. In the context of assigning drive types, it is sometimes helpful to know whether or not the BIOS supports "change-line" detection (i.e., the drive can detect whether the drive door is open) for the drive in question. One indirect inference is available since the low-capacity 5 1/4 " drives are unable to provide a change-line facility. >> It doesn't go into more details regarding the change-line detection support detection right there, but I'll report in another reply (to this message) if I find more elsewhere. Regards, Chris ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Freedos-kernel mailing list Freedos-kernel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-kernel