Hi Eric, Thanks a lot for teaching me more about how the different DOS'es and BIOS'es work with respect to disk partitioning. This is a very interesting thread for me to follow.
Bob On 11/12/12 3:20 PM, Eric Auer wrote: > Hi Karen, (Bob: please see below...) > > important snippet from > https://en.wikipedia.org/wiki/DR-DOS#After_Novell > > Support for LBA and FAT32 originally was a DRFAT32 device driver, > so in old DR DOS, you first have to boot from a FAT16 partition > which is entirely in the first 8 GB of your disk and less than > 2 GB in size, I would assume. Also, FDISK may be limited, so you > better use something else than old DR DOS FDISK to partition... > > In DR DOS 7.04 and newer, things were getting better, but it is > unlikely that you have that version. However, based on OpenDOS > 7.01 source code, EDR-DOS implemented a free kernel with FAT32 > and LBA support (version "DR DOS 7.01.08" of July 2011). Due to > license conflicts with the free improvements, DR DOS 8.0 and 8.1 > have been discontinued, so DR DOS 7.03 (from the year 1999!) is > the most recent DR DOS. I strongly recommend EDR DOS instead: > > http://www.drdosprojects.de/index.cgi/download.htm > (just get the binaries, otherwise you need source+patch+compiler) > > Note that EDR DOS comes with very little extra software - simply > use the extra software of another DOS like DR DOS or FreeDOS :-) > > > > Hi Bob, > >> I wonder what the brandand firmware revisions the harddrive(s) in >> question are and whether or not they have a size-limiting jumper >> connected. Doesn't such a jumper, in combination with hardcoded BIOS >> settings, control the cylinders-heads-sectors that "the DOS" flavor >> sees? And doesn't DOS itself need a device driver in order to talk > The last time that I saw such a jumper, it limited the > size to 32 GB to avoid crashes with broken BIOSes. Also, > some drives came with software to limit them to 128 GB > to avoid yet other compatibility issues. Unless you have > a VERY old BIOS (early 1990s) you do not need drivers: > > The BIOS will support sizes up to 128 GB using LBA, or > in newer BIOS versions even up to 2 TB and more. Older > DOS versions only support CHS which is where "geometry" > (cylinder head sector) matters. If at all possible, use > DOS versions and partition types with LBA, as those do > not need to worry about geometry. For example MS DOS 4 > does not support LBA, so you must use CHS and geometry > must match between BIOS *and* partitioning *and* DOS. > > The BIOS will usually select some default with many > (240, 254, 255?) heads for big disks, to get as much > of the disk as possible in the first 1024 "cylinders" > but you still do not get further than 8 GB. So if you > must use CHS, pretend that your whole disk is smaller. > Even MS DOS 4 can then use up to 2 GB per drive letter > but do not get too close to 2048 MB or it will fail. > > Really old (also early 1990s, 1980s) BIOS versions do > not support geometry settings above 16 heads, so you > would need "dynamic drive overlay" or "ontrack" style > "drivers" (actually installed as sort of boot loader) > to get beyond 500 MB (0.5 GB). > > That said, a normal FreeDOS with FAT32 support can use > the first 2 TB of your disk as long as you use LBA FAT32 > type partitions. You can even make one partition of that > size if you do not want to use several drive letters... > > Using SSD is no problem for DOS at all, only the size > matters, the BIOS supports it all. If DOS would KNOW > that the disk is SSD, it could get a bit more speed. > Also, modern harddisk and SSD allow parallel access to > gain speed, but DOS is not multitasking things anyway. > > Note that DOS drivers like UIDE allow faster data transfer > in cases where the "driver" built into the BIOS is slow. > So DOS drivers for disks do exist, but are not essential. > > > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. Get in-depth insight into apps, servers, databases, vmware, > SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from $795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > _______________________________________________ > Freedos-user mailing list > Freedos-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-user > ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
