Eric, >> ... I issue 28-bit commands for up to 28-bit addresses, >> while I issue 48-bitters for larger addresses. Runs >> fine! > > I meant if the BIOS only sees the first 2^N sectors and > the partition table describes more than that, UIDE will > probably not modify the BIOS-reported disk size: So on > one side, UIDE could help DOS to access more of a disk > than the BIOS, but on the other, that might be unsafe...
Once again, UIDE is written to be a "physical" disk driver. It has absolutely NO logic that interrogates for drive size during init, and it simply "takes orders" from DOS re: what physical sectors it reads or writes. Any idea that a disk is limited to 128-GB, 2-TB, etc. is "unknown" to UIDE -- it simply handles up to 8-GB using 24-bit "CHS" commands or up to (8-GB * 8-GB) using 48-bit "LBA" commands. My intent with UIDE was to write a driver at the "physical" level, so it is NOT-at-all dependent on any DOS constraints which may differ between MS-DOS, FreeDOS, DR-DOS, etc. By depending on only (A) Int 13h and (B) 48-bit LBA addresses, and NOTHING else, UIDE is thus "DOS independent"! > PS: LBACACHE does treat access beyond 2^32 sectors as a > flush event and will not cache the additional sectors. > Of course MBR based partitions cannot go > 2^32 either. Why is a "flush" needed? LBACACHE should work the same as UIDE, i.e. it "takes orders" from the DOS system about what sectors to read/write. If current 32-bit DOS directories cannot store info about files past 2-TB, LBACACHE shouldn't EVER get a read/write request for sectors above that limit, unless the DOS system has CRASHED! > PPS: What do you think about using Ontrack/Ezdrive style > load-before-kernel drivers to map from 4k to 512 sectors? No experience with such drivers. OnTrack never worked for me, same as it did not for many others. I see 2 problems: (A) It adds another level of software complexity which many users will not understand, and (B) it might still require a BIOS that handles 512-byte sectors, so the "special" driver can be read initially! Actually, I agree with other posts in this thread that 512 byte sectors at-least for "booting" shall be with us for a long time, so "special" drivers seem to be unnecessary! Let the 512-byte sectors handle "boot" until UIDE/LBACACHE are loaded, then more-efficient 4K-byte sectors (or whatever) can be supported using those drivers. ------------------------------------------------------------------------------ RSA(R) Conference 2012 Mar 27 - Feb 2 Save $400 by Jan. 27 Register now! http://p.sf.net/sfu/rsa-sfdev2dev2 _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
