vanpelt@unisv.UUCP (Mike Van Pelt) (04/07/88)
Someone managed to create a partition of unknown type on our PC/AT clone here at work, and the DOS FDISK program won't touch it. I would like to delete the thing (It's 16 Meg!) but am kind of at a loss at the moment -- sure, I could low-level format the hard disk, but that seems excessive (not to mention being more work than I care to go to at the moment.) Does anyone know how to delete a partition that FDISK declares untouchable because it is type "UNKNOWN"? -- Mike Van Pelt Unisys, Silicon Valley vanpelt%unisv@ubvax.ub.com Bring back UNIVAC! ...uunet!ubvax!unisv!vanpelt
rgc@edison.GE.COM (GENIUS Open Architecture) (04/18/88)
In article <290@unisv.UUCP>, vanpelt@unisv.UUCP (Mike Van Pelt) writes: > Someone managed to create a partition of unknown type on our PC/AT > clone here at work, and the DOS FDISK program won't touch it. I > would like to delete the thing (It's 16 Meg!) but am kind of at a > loss at the moment -- sure, I could low-level format the hard disk, > but that seems excessive (not to mention being more work than I care > to go to at the moment.) Does anyone know how to delete a partition > that FDISK declares untouchable because it is type "UNKNOWN"? I had a similar experience with a split 20 Meg drive... after using Norton and a variety of other tools, I reorted to the low level format, FDISK then format... If there is an easier way, I would like to know, too. Thanks -- Rick Carl GE Fanuc - Charlottesville, VA 22901 rgc@edison.GE.COM rgc@edison.UUCP
jrv@siemens.UUCP (James R Vallino) (04/25/88)
The structure of the partition table is shown in the IBM Technical Reference.
The table is stored in the first sector of the hard disk.
Removing an unwanted partition is a fairly simple process using DEBUG.
Here is the procedure which I used when I had the same type of problem:
1. Read the boot record/partition table into memory. Assemble the following
program in memory using DEBUG and run it to the nop:
mov ah,2 ;ah = 2 read disk, 3 write disk
mov dl,80 ;dl = 80 - 81 for first or second hard disk
mov dh,0 ;head 0
mov cx,1 ;cylinder 0 sector 1
mov al,1 ;read/write 1 sector
mov bx,200 ;es:bx => data buffer for read/write operations
int 13 ;do the disk operation
nop ;run program to this point
2. The partition table will start at offset 3be if the data buffer is 200 as
above. Data for the four partitions start at:
3be partition 1 (offset 1be in sector)
3ce partition 2 ( 1ce )
3de partition 3 ( 1de )
3ee partition 4 ( 1ee )
3fe 55 AA (these two bytes must end the boot record)
To wipe a partition off the face of the disk zero all the bytes in its
area of the partition table.
3. After modifying the partition table change the program above so that AH is
set to 3 (write disk), hold your breath, and run it again to write the
modified partition table to disk.
--
Jim Vallino Siemens Research and Technology Lab.,Princeton, NJ
CSNET: jrv@siemens.siemens.com
UUCP: {ihnp4,philabs,seismo}!princeton!siemens!jrvpaula@bcsaic.UUCP (Paul Allen) (04/30/88)
In article <1479@edison.GE.COM> rgc@edison.GE.COM (GENIUS Open Architecture) writes: >In article <290@unisv.UUCP>, vanpelt@unisv.UUCP (Mike Van Pelt) writes: >> Someone managed to create a partition of unknown type on our PC/AT >> clone here at work, and the DOS FDISK program won't touch it. I [..] > Does anyone know how to delete a partition >> that FDISK declares untouchable because it is type "UNKNOWN"? > >I had a similar experience with a split 20 Meg drive... >after using Norton and a variety of other tools, I reorted to >the low level format, FDISK then format... >If there is an easier way, I would like to know, too. > We ran into this problem when trying to remove Xenix from a hard disk. It turns out the way to remove a Xenix partition is to boot Xenix from floppy and use the Xenix fdisk program. If you boot from the hard disk, fdisk fails because you're trying to remove a partition that has a mounted file system on it! It's been a year or so since I had anything to do with Xenix, but this information is probably still valid. At least, it's another avenue to explore. Paul Allen -- ------------------------------------------------------------------------ Paul L. Allen | paula@boeing.com Boeing Advanced Technology Center | ...!uw-beaver!ssc-vax!bcsaic!paula
keithe@tekgvs.TEK.COM (Keith Ericson) (05/01/88)
In article <3398@tekgvs.TEK.COM> keithe@tekgvs.UUCP (Keith Ericson) writes: >A program called edpart was posted to the net about a year ago. > Uh - never mind.... I just realized that I'm 'sposed to post these to the binaries group. I'll cancel the original and re-post there... keith
backstro@silver.bacs.indiana.edu (John Q. Public) (05/03/88)
In article <5134@bcsaic.UUCP> paula@bcsaic.UUCP (Paul Allen) writes: >In article <1479@edison.GE.COM> rgc@edison.GE.COM (GENIUS Open Architecture) writes: >> Does anyone know how to delete a partition >>> that FDISK declares untouchable because it is type "UNKNOWN"? >> > >It turns out the way to remove a Xenix partition is to boot Xenix from >floppy and use the Xenix fdisk program. > If you're using DOS, and want to play it safe, look into a copy of Disk Manager by OnTrack. It allows use of large hard drives much as DOS 3.3 does, supports low-level formatting, and manipulation of the partition table -- addition and deletion of partitions. It has caused me no problems. (I have no connection with OnTrack). If you're adventurouse, several fdisk-type programs were posted in comp.os.minix for people who needed to add non-DOS partitions. -- backstro@silver.bacs.indiana.edu