From owner-freebsd-questions Thu Feb 23 22:29:36 1995 Return-Path: questions-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.9/8.6.6) id WAA01386 for questions-outgoing; Thu, 23 Feb 1995 22:29:36 -0800 Received: from kitten.mcs.com (Kitten.mcs.com [192.160.127.90]) by freefall.cdrom.com (8.6.9/8.6.6) with ESMTP id WAA01380 for ; Thu, 23 Feb 1995 22:29:34 -0800 From: krnlhkr@mcs.com Received: from mailbox.mcs.com (Mailbox.mcs.com [192.160.127.87]) by kitten.mcs.com (8.6.10/8.6.9) with SMTP id AAA26537; Fri, 24 Feb 1995 00:28:54 -0600 Received: by mailbox.mcs.com (/\==/\ Smail3.1.28.1 #28.5) id ; Fri, 24 Feb 95 00:37 CST Message-Id: Date: Fri, 24 Feb 95 00:37 CST Subject: Re: [Q] FreeBSD 2.0R - fdisk is non-destructive? To: David Lim , questions@FreeBSD.org X-Mailer: AIR Mail 3.X (SPRY, Inc.) Sender: questions-owner@FreeBSD.org Precedence: bulk I've attached the original message below so you can see my reply first, then check the data which is long. Since 3 different fdisks (DOS, BSD, and the dos_tools) show the partition table to be correct, I have to think that your DOS filesystem is hosed. DOS reports free space on the disk based on the number of clusters in the file system. Int21h Function36h reports total clusters and remaining clusters. This is the FAT table we know and love so well. I haven't peeked at the BSD dosfs code, but my guess is that the call df makes computes the freespace the same way. So, your FAT or the number of clusters may have gotten hosed in your DOS filesystem. You can run chkdsk under DOS, but be prepared to lose some files. There are several reasons for DOS filesystem corruption: sometimes it just "happens", a virus can do it, or BSD could have hosed it. If you hadn't mounted a DOS filesystem under BSD I don't think BSD did it. If you make the DOS partition with BSD's fdisk, you might not want to do this. Generally I make DOS partitions with DOS's fdisk, BSD with BSD's, etc. I would back up what I have, and do a chkdsk. It will report if the FAT is corrupted, and that would explain what is wrong. If that is the case, you will want to find out as soon as possible anyhow because you will eventually lose files. Hope that helps and let me know how it turns out or if you need more help. -Louis <---- Begin Included Message ----> <---- Begin Included Message ----> I just installed FreeBSD 2.0-R from the Walnut CD-ROM on a 1 Gbyte drive. I created two slices one for DOS and one for FreeBSD. When I boot DOS, I run fdisk, and it shows the slice sizes correctly. However, the DOS dir command still reports free space relative to the entire disk. E.g. it says 100 Mbytes used, 900 Mbytes free. Is this just a DOS bug of some sort? I'm worried that DOS will overwrite sectors assigned to FreeBSD. <---- End Included Message ----> An additional piece of information. When I first partitioned the FreeBSD slice, I first imported the MS-DOS slice to partition e. However, when I do a df under FreeBSD, it shows the same incorrect information as the DOS DIR command. df shows my /dev/sd0e (MS-DOS slice) as having a capacity the size of the entire disk! I've looked through the FAQ and searched through the mailing list archives. The only thing I've come up with is the SCSI card setting for 1 Gbyte drives. I have this turned ON on the Buslogic card. Perhaps I should turn it off? I tried turning it off, and tried booting (no reinstall) both DOS and FreeBSD, they both still had the same problem, showing the MSDOS partition occupying the entire drive. Perhaps I should turn it off and reinstall all of FreeBSD and Windows/DOS? Perhaps I should use the real geometry of the drive, and just make sure that the partition of DOS resides within 1024 cylinders again using the real geometry of the drive? This just doesn't sound quite right to me. So I guess fdisk is destructive? Everyone who has partitioned their disk to install FreeBSD, had to re-install DOS and windows? I seem to recall a message someplace saying that some Conner drives have some sort of auto-translation of the cylinders? And that some special care needs to be taken when writing the MBR code? Unfortunately I can't seem to track down this message. --------------------------------------------------------------------------- --- Output of DOS fdisk Partition Status Type Volume Label Mbytes System Usage C: 1 A PRI-DOS Micron 501 FAT16 49% 2 non-DOS 512 51% --------------------------------------------------------------------------- --- Output of tools\dos-tools\pfdisk 0 geometry 1013 64 32 (cyl hd sec) # ID First (cyl) Last (cyl) Nmae #start, length 1 6 0 500 Dosbi 32,1026016 2 165 501 1012 unkno 1026048,1048576 --------------------------------------------------------------------------- --------------------------------------------------------------------------- --- Output of /sbin/disklabel # /dev/rsd0a: type: SCSI disk: label: MBR based label flags: bytes/sector: 512 sectors/track: 32 tracks/cylinder: 64 sectors/cylinder: 2048 cylinders: 1013 rpm: 0 interleave: 0 trackskew: 0 cylinderskew: 0 headswitch: 0 # milliseconds track-to-track seek: 0 # milliseconds drivedata: 0 8 partitions: # size offset fstype [fsize bsize cpg] a: 51200 1026048 4.2BSD 1024 8192 16 # (Cyl. 501 - 525) b: 65536 1077248 swap # (Cyl. 526 - 557) c: 1048576 1026048 unused 0 0 # (Cyl. 501 - 1012) d: 2074880 0 unused 0 0 # (Cyl. 0 - 1013*) e: 1026016 32 MSDOS # (Cyl. 0*- 500*) g: 931840 1142784 4.2BSD 1024 8192 16 # (Cyl. 558 - 1012) Warning, revolutions/minute 0 super block size 0 --------------------------------------------------------------------------- --- Output of /sbin/fdisk ******* Working on device /dev/rsd0a ******* parameters extracted from in-core disklabel are: cylinders=1013 heads=64 sectors/track=32 (2048 blks/cyl) parameters to be used for BIOS calculations are: cylinders=1013 heads=64 sectors/track=32 (2048 blks/cyl) Warning: BIOS sector numbering starts with sector 1 Information from DOS bootblock is: The data for partition 0 is: sysid 6,(Primary 'big' DOS (> 32MB)) start 32, size 1026016 (500 Meg), flag 80 beg: cyl 0/ sector 1/ head 1; end: cyl 500/ sector 32/ head 63 The data for partition 1 is: sysid 165,(386BSD) start 1026048, size 1048576 (512 Meg), flag 0 beg: cyl 501/ sector 1/ head 0; end: cyl 1012/ sector 32/ head 63 The data for partition 2 is: The data for partition 3 is: <---- End Included Message ----> ---------------------------------------------------------------------- Louis J. Giliberto, Jr. ! Support the Free Software Foundation krnlhkr@mcs.com ! ----------------------------------------------------------------------