GOOD2USE Knowledge Network Windows Operating System MBRScan

PC Knowledge Base - Windows Operating System MBRScan

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MBRSCAN (downloadable here) is a PC-DOS program which dumps MBR (Master Boot Record) and boot record of each partition and analyses partition table entries.
If you have some knowledge about hard disk, you can figure out partition and boot problems using this tool. The MBRSCAN is also good for understand partition table structure.

MBRSCAN.EXE is a DOS program. It works under PC-DOS, DOS/V, DOS window of OS/2 and Windows 98.
If you want to run this program against boot drive, just type MBRSCAN. The current version of the MBRSCAN supports up to 15 logical drives.

Options

Usage: MBRSCAN [-opt][drive]

opt: sd = Suppress Dump
st = Suppress Partition Table Report
sm = Suppress Partition Map
sf = Suppress Free Space Report

drive: 0 = FD-A
1 = FD-B
80 = 1st HDD
81 = 2nd HDD ...
default = 80 (1st HDD)

MBRSCAN -? will display help screen.

Options will suppress a part of reports, detail of options as follow.

sd Suppress dump of the MBR and boot record.
st Suppress partition table report.
sm Suppress partition map report.
sf Suppress free space report.

Drive parameter is same as INT13 BIOS call parameter. Default is 80, it is boot drive. It is also known as drive-1 of the PC DOS FDISK.

Output

Reports LBA mode is supported by INT13 BIOS call or not. If LBA mode is not supported, it will display Non-LBA mode. If LBA mode is supported by BIOS, following operation will perform using LBA mode.

DRV:80 CC=03E0h(992), HH=80h(128), SS=3Fh(63), BLKS=7A1000h(7999488)

Geometry information gathered by INT13 BIOS call. CC represents number of cylinders, HH represents number of heads and SS represents number of sectors. BLKS means number of sectors available of this HDD. BLKS is calculated using CCHHSS value in Non-LBA mode.
Geometry function sometimes fails under Windows 9x.
The wrong number of heads value may be seen under OS/2 MDOS environment.

MBR(Master Boot Record) dump. This is a first record to be read when boot the PC from the hard disk. Which consists of bootstrap and primary partition table. The MBR is located first sector of the hard disk. Address is 0 in LBA mode and CCC-HH-SS = 000-00-01 in Non-LBA mode.

Partition table starts with offset address 0x1BE. There are 4 entries and each entry has 16 bytes. 1 - Partition Table Entry = 0, first '1' represents primary partition. In extended partition, this number would be 2 or larger value. Last numeric means partition table entry number. This must be between 0 and 3.
Partition table detail is also displayed. Detail of partition table will mention later.
In this example, partition ID is Extended.
If this is a normal drive (FAT32 for example), dump of boot record will be followed.

Summary of partition map. ABSOLUTE START and END values are real sector addresses (LBA mode address) calculated from START and BLOCKS in PARTITION-TABLE.
In Non-LBA mode, partition map with CCC-HH-SS address is also displayed.

[ FREE SPACE ]

None.

Free space display in LBA mode address. If geometry of the disk drive was not saved, free space for last part could not be calculated.

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