Hi Johnson, as said, I updated my BIOS from "max 32 or 64 GB" (not sure which, but crashed with bigger disks) to "max 128 GB". Then I plugged an even bigger disk, and BIOS and FreeDOS were able to access the first 128 GB just fine, but FreeDOS hit the 128 GB barrier when trying to enumerate all partitions and showed an error message (because it cannot know that all partitions beyond the first 128 GB are Linux ones which are uninteresting for DOS anyway ;-)). I would say that this is pretty nice performance so far.
Again, the problem is in BIOS. FreeDOS is able to use FAT32 (up to 2^28 clusters, recommended for max 128 GB but you can use bigger drives if you want) and 32bit sector numbers (up to 2 TeraBytes). It would be relatively easy to use 64bit partition positions to allow "infinite" disk size with up to 2 TB per drive letter, but the normal partitioning scheme itself is utterly unable to describe disks which are bigger than 2 TB. Tom already suggested to support the successor of partition tables: That would support on-the-fly repartitioning (well, as pointed out earlier, DOS reboots in seconds anyway, and some programs would get confused by dynamic drive letter changes and it would take extra RAM) and huge disks. But actually I have no idea why I would want my FreeDOS to access more than the first 128 GB of my disk anyway ;-). The BIOS limit to 128 GB (134 or so if you use "decimal GB") is very common, and our UDMA2 driver has the ability to bypass it, but as the kernel does not re-read partition tables after you load UDMA2... Imagine the rest. A BIOS which sees 120 GB does not necessarily see 160 GB. But a BIOS which sees 160 GB will, unless it has a bug, see HUGE disks, up to at least 2 TB but, if prepared for 64bit operating systems, even bigger than that. Actually 32/64 bit operating systems do not care for BIOS disk drivers at all anyway. Who knows ;-). Eric ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
