I've got a wierd problem that maybe someone here may have run into. Windows related but tied to embedded file systems. We've got a third party file system on large USB hard drives and small CompactFlash with our embedded system. We've got a Windows driver for the file system which we can use for convenience. We have not been putting any partition tables or MBR on the large hard drives (this wasn't planned, but we're stuck with a lot of these in the field). Windows will see the small CompactFlash drives just fine and use the third-party file system, with or without an MBR. But the large hard drives it refuses to recognize, and treats it like unformatted disks (some disks will even crash XP). My theory is that there is a Windows feature that large hard drives have to have an MBR, whereas small drives use a legacy support (ala floppies). The questions are: is this theory right? Is it mandatory to have an MBR, even on drives that don't need to be booted via BIOS? Is there any workaround to try and tie these disks to a third party driver in Windows, or is this a completely hopeless cause? -- Darin Johnson
Large drive without partitions
Started by ●August 14, 2008
Reply by ●August 15, 20082008-08-15
> The questions are: is this theory right? Is it mandatory to > have an MBR, even on drives that don't need to be booted > via BIOS? Is there any workaround to try and tie these > disks to a third party driver in Windows, or is this a > completely hopeless cause?I thought the MBR contains the partition table so all hard disks need one ? -- Boo
Reply by ●August 15, 20082008-08-15
Boo wrote:> >> The questions are: is this theory right? Is it mandatory to >> have an MBR, even on drives that don't need to be booted via >> BIOS? Is there any workaround to try and tie these disks to a >> third party driver in Windows, or is this a completely hopeless >> cause? > > I thought the MBR contains the partition table so all hard > disks need one ?The first segment on track 0 holds both the MBR and the partition table. The table is necessary to use the disk. The MBR is only needed to boot from that disk. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section.
Reply by ●August 15, 20082008-08-15
On Thu, 14 Aug 2008 18:27:02 -0700 (PDT), Darin Johnson <darin@usa.net> wrote:>The questions are: is this theory right? Is it mandatory to >have an MBR, even on drives that don't need to be booted >via BIOS? Is there any workaround to try and tie these >disks to a third party driver in Windows, or is this a >completely hopeless cause?I guess it's the fact that harddisks are considered "fixed" while CF cards are "removable" like floppies. Windows treats these device types differently. You can't use NTFS on "removable class" type devices. OK, you can have USB harddisks, but these are "fixed" devices on an USB bus, even if you can remove them. It's just a matter of different device classes, so don't take "fixed" and "removable" too literally. Mit freundlichen Gr��en Frank-Christian Kr�gel
Reply by ●August 15, 20082008-08-15
On Thu, 14 Aug 2008 18:27:02 -0700 (PDT), Darin Johnson <darin@usa.net> wrote:>I've got a wierd problem that maybe someone here may have run into. >Windows related but tied to embedded file systems.I've seen memory sticks that came from the factory without a partition table, putting the one single partition on the linux equivelent of /dev/sda instead of /dev/sda1. They work fine w/ both windows and linux. Once when I was new to linux and didn't know what I was doing, I initialized and mounted a second hard drive as /dev/hdb, which is to do it without a partition table.
Reply by ●August 15, 20082008-08-15
On Aug 15, 9:42=A0am, AZ Nomad <aznoma...@PremoveOBthisOX.COM> wrote:> I've seen memory sticks that came from the factory without a partition > table, putting the one single partition on the linux equivelent of > /dev/sda instead of /dev/sda1. =A0They work fine w/ both windows and > linux.Yes, this is essentially what's happening with me. The format software just used the first partition, or if no table, the entire disk. Which is all fine on Windows, if it's under 2G or so, but it doesn't work on the larger drives. Just wondering if there's any hack for Windows to get around this, or if I have to copy the data to a new drive first.
Reply by ●August 15, 20082008-08-15
On Fri, 15 Aug 2008 08:51:15 -0400, CBFalconer <cbfalconer@yahoo.com> wrote:>Boo wrote: >> >>> The questions are: is this theory right? Is it mandatory to >>> have an MBR, even on drives that don't need to be booted via >>> BIOS? Is there any workaround to try and tie these disks to a >>> third party driver in Windows, or is this a completely hopeless >>> cause? >> >> I thought the MBR contains the partition table so all hard >> disks need one ? > >The first segment on track 0 holds both the MBR and the partition >table. The table is necessary to use the disk. The MBR is only >needed to boot from that disk.sector, not segment. The table is only needed if you want to use the drive under the control of most operating systems. If you use the BIOS I/O routines, the table is not needed. -- ArarghMail808 at [drop the 'http://www.' from ->] http://www.arargh.com BCET Basic Compiler Page: http://www.arargh.com/basic/index.html To reply by email, remove the extra stuff from the reply address.
Reply by ●August 15, 20082008-08-15
Darin Johnson wrote:> Yes, this is essentially what's happening with me. The format > software just used the first partition, or if no table, the entire > disk. Which is all fine on Windows, if it's under 2G or so, > but it doesn't work on the larger drives.That figure of 2 Gigabytes may be the clue here. That happens to be, among other things, the maximum size of FAT16 (theoretically it can go up to 4G, but it's not safe to assume all systems can actually handle that). There was a time when people still using the original version Windows 95 (a.k.a. "W95a") got to know that limit better than they ever wanted to, having to partition multi-gigabyte HDs into many file-systems of 2 GB each. It wouldn't surprise me a lot if drives without a partition table (a.k.a. "super-floppy format") only allowed FAT16, but not FAT32 or NTFS.> > Just wondering if there's any hack for Windows to get around > this, or if I have to copy the data to a new drive first.
Reply by ●August 15, 20082008-08-15
On Aug 15, 9:19=A0am, Frank-Christian Kruegel <dontmai...@news.invalid> wrote:> You can't use NTFS on "removable class" type devices.Not true. I have a 256M USB Flash Drive that is formatted with NTFS. Win2K (and up) read/write it "just fine". G.
Reply by ●August 15, 20082008-08-15
ArarghMail808NOSPAM@NOT.AT.Arargh.com wrote:> CBFalconer <cbfalconer@yahoo.com> wrote: >> Boo wrote: >>... snip ...>> >>> I thought the MBR contains the partition table so all hard >>> disks need one ? >> >> The first segment on track 0 holds both the MBR and the partition >> table. The table is necessary to use the disk. The MBR is only >> needed to boot from that disk.\.> sector, not segment. > > The table is only needed if you want to use the drive under the > control of most operating systems. If you use the BIOS I/O > routines, the table is not needed.True. I thought the word segment looked peculiar. :-) Anything that needs the disk partitioned into effective drives needs the table. The bios reads that first sector, and transfers control to it (MBR code) if the read didn't fail. -- [mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section.
