> Additionally, it wants all files to have short names (which naturally > aren't available on ext or BtrFS) and expects these short names to be > stored in all-caps and there is hardly any international character set > support. These name/path restrictions are partially lifted by the LFN API > (which the FreeDOS kernel doesn't support natively) but intercepting and > handling LFN API calls in a DOS redirector file system driver is rather > complicated (because the regular redirector interface only supports the > SFN API). > > If a driver shows some or all files and directories only on the LFN API, > LFN-unaware programs won't be able to access these files and directories. > Hence, typically DOS redirector file system drivers for file systems > without short names dynamically invent short names on their own, hopefully > without conflicts. (SHSUCDEX apparently does this, but this might be more > difficult to achieve well in a read-write driver.) >
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, you have the long filename problem. In Unix systems, the filename can be a short letter to grandma. For example, I just created these two 1-line files in my DOSEmu directory: $ ls -sk D* 4 Dear Grandma, I hope you are fine. I am fine too. Tomorrow, we are going on a boating trip. I think it will be fun. Will write again soon. -me 4 Dear Grandma, I hope you are fine. I am fine too. We had a lot of fun on the boating trip. Next week, I hope to try skydiving and lion-taming. Will write again soon. -me 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 Granted, that's a very extreme example, but you get the idea that a long filename gets munged into 5 visible characters, a hash value, and the extension. It's a similar method with other long-to-short filename mapping schemes. Workable for some folks, but even if I applied this 5-character rule to my ~/Documents directory on Linux the names get very hard to read: 2011E~12.PDF ALUMN~12.PDF CALIB~12 CC50_~12.MOB CIORE~12.PDF CONFI~12.PDF D12-0~12.PDF DATAB~12.KDB DOCTO~12 E-MAI~12.PPT ERS11~12.PDF ERS11~34.PDF INSTA~12 So you can do it, but the challenge is making these files addressable by DOS in short namespace, in a user-accessible way. -jh ------------------------------------------------------------------------------ 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
