Kevin Wolf <[email protected]> writes:
> Am 27.01.2023 um 01:00 hat Csepp geschrieben: >> Would it be possible to store the metadata for emulated FAT partitions >> backed by host directories? It would make installing Windows 98 much >> more seamless, since it would be able to set the boot flag during >> install. I have a 9front install that uses no block devices and gets its >> root file system via a simple 9P server, I've found that extremely >> useful, since it lets me back up or modify files directly from the host. >> >> I don't have that much free time, but if it wouldn't be too difficult to >> implement this and someone helped, I could try to do it myself. But >> honestly I would be super thankful if someone else implemented it >> instead. > > Running a whole OS from a vvfat backend sounds quite adventurous... > (Running anything on vvfat, especially in read-write mode, is a little > adventurous because it's a clever, but not very supportable hack that > has known bugs, but a whole OS is a step further.) I've only ever used > it for transferring individual files. > > Of course, you also need to be careful with accessing the filesystem > from the host and the guest at the same time - strictly speaking, once > you change anything from the host, a running guest sees a broken disk > than randomly changed and together with guest caches that could corrupt > everything. So avoid that if you don't want to tempt fate. Yeah, that only worked on 9front because it was designed to be network transparent from day 1. > Technically it should be possible to make writes to the boot sector etc. > persistent, you just need a place to store them. I imagine an additional > special file could do the trick. If you have it in the same directory, > you would get collisions with files of the same name in the guest file > system. > > So I suppose you would use an image file outside of the directory and > configure it like -blockdev vvfat,dir=/tmp/foo/,mbr=/tmp/foo_mbr.img > with a separate option specifying its path. > > I'm not sure if it would be better to override parts of the image with > the actually correct data according to the generated file system. > > I doubt you'll find anyone to make this hack for you, but if you feel > like it, it sounds like it should be possible. > > Kevin Thanks, at least now I know it's somewhat feasible to implement it. In the meantime I also tried running the software I want to use in Wine, which didn't work completely, but we'll see if the bugs are annoying enough to make me attempt this. Or I'll swallow having a disk image for the OS and a separate virtual FAT for everything else...
