> I think the big limitation will be addressable filesystem space. Btrfs > can support 2^64 files, and 16EB volumes. That's a wee bit too much > for DOS to handle. > > Even if you have a Btrfs that's fairly small, say small enough to be > addressable by DOS,
Assuming the driver has enough space for its internal tables, the redirector file system interface has no direct restrictions on the number of files, or on low-level details of a file system such as how many 'sectors' or 'clusters' or 'blocks' of whatever size it has. However, the regular SFT implementation allows only up to 255 simultaneously opened file handles (including the three handles typically referring to CON, AUX, and PRN for the first five 'std' handles). Additionally, file sizes are limited to 4 GiB (or only 2 GiB even, in some implementations) unless SFTs and APIs are extended to eg 64-bit seek offsets (as implemented by EDR-DOS). Like LFNs, the 64-bit seek offsets are not supported on the regular redirector interface, so a file system driver would have to work around that additionally (similar to providing LFNs manually), or extensions to that interface are necessary as well. (I don't think EDR-DOS defines such an extension as of yet?) > you have the long filename problem. Yes, as mentioned. > DOSEmu presents a local Linux folder as a drive to FreeDOS, using > long-to-short filename conversion. So I can see these files in > FreeDOS, but they have different names: > > DEARG~10.-ME > DEARG~LC.-ME Oh, doesn't its redirector driver provide long names on the LFN API? > So you can do it, but the challenge is making these files addressable > by DOS in short namespace, in a user-accessible way. Yes, as I hinted at, it is particularly difficult because it doesn't suffice to just dynamically shorten each name _individually_ as then the same short name alias might be invented twice in the same directory. Such conflicts must be avoided; otherwise (at best) the duplicate name will actually access only one of the files. 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-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
