Win2k "secret weapon" disk editing (a)

1. Extended partition structure and logical volume background knowledge

A physical hard disk can have multiple partitions, relatively simple and more commonly used is: first Part of the space is divided into primary partitions, and the remaining space is used as the extended partition. The capacity of the early hard disk was very small, and at that time there was a plan to simply use the entire hard disk as a primary partition. In either case, it must be clear that the 0 cylinder 0 head (disk surface), which is the 0 track of which disk surface the 0 head is located (regardless of how many sectors the track is divided into), does not belong to any Partitioned, that is, here is an area reserved by the system, and this part of the area is hidden, in this reserved area, there is only one master boot record. The general primary partition then hides the zone establishment. Then the primary partition is subsequently established, and it belongs to the extended partition.

Strictly speaking, no matter which type of partition, it can not be directly used by the operating system, you need to establish at least one or more "logical volumes" in the partition.----This is of course foreigners The method of salutation, we generally call it "logical drive". After the logical drive is divided, it can be formatted, regardless of the primary partition or extended partition should be handled as such! only if. In order to install the operating system or be used by the system.

Let's say that partition tables, whether primary or extended, and logical drives, are partitioned and represented using partitioned tables. Therefore, there is a partition table of its own. All partition tables adopt the representation of “backward connection”, that is, the partition table of the current partition or logical drive must store the phase in addition to the current partition information. The partition table of the next partition (or logical drive) of the neighbor. That is, any partition or logical drive must "know" the exact location of the next partition adjacent to it. If the partition itself is the last partition, only the information representing its own partition is stored. For example, at the end of the article is a schematic diagram of a partition table structure that divides an extended partition into three logical drives: As can be seen from the figure, each logical drive has four reserved locations for the partition table, but Only the first two are actually used in the extended partition. The first one is the current partition and the second is the next partition. The same is true for the second logical drive. To the last one, only the first partition table is used.

Each logical drive has its own boot sector. In the DOS era, this sector is simply called a DOS boot sector. Note that this sector is not a duplicate of the primary boot sector reserved by the physical hard disk, but is controlled by the operating system. At the end of this boot sector, 0X55AA is also used as a sign of successful boot.

2. How to display the basic situation of all partitions

a. In windows2000, you can also display all partitions without using the support tool tool, you can open from the control panel Management & rdquo;, there is a "disk management", mouse click to display the partition status of all disks.

I opened it on my own machine as shown above. However, when this method is turned on, the information displayed is small and cannot be edited and modified.

b. Use the DiskProbe tool to display and edit extended partition information. How to open the DiskProbe tool specifically, the first two parts have introduced the operation process in great detail. Here only talk about the new problem you will encounter: after opening DiskProbe, you want to display the extended partition, you must select the logical volume (drive). You can click on "Drive -> Logical Volume (Drive)" in the menu, a selection dialog will appear, allowing you to make a logical drive selection;

To the left of the scroll bar of the dialog, the column The logical drive is available for selection. The selected method is to double-click one of the buttons, and finally click the OK button;

then select the starting sector and the number of sectors to read, in Sectors Menu, click Read dialog box to let you choose the starting sector and the number of sectors;

Generally use the default value displayed, and click the Read button without change.

The screen displayed in the next step is shown in Figure 4;

The information along with the boot sector is displayed in bytes. This is not intuitive, especially for people with less experience, it may not understand at all. Need to change the display mode, you can click Partition table in the View menu, the displayed screen has been seen before, here will not repeat the illustration. If you want to modify the extended partition information, you can enter the appropriate number directly in the edit box.

3. Troubleshooting Boot Sectors

Each logical volume has its own boot sector, and the boot sector is a place where some viruses can easily invade, even including NTFS partitions. It is also difficult to escape. Although the mechanism of viral infection is well known. But there is one more point to note: Given that most viruses use the BIOS's INT13 interrupt to operate on the absolute sector of the disk. In Windows 2000, the protected mode is used instead of the original BIOS routine to read and write to the disk. This reduces the chance of some viruses from invading to a certain extent, but this requires preconditions to run Windows 2000. When the computer is running other operating systems, there is still the possibility of being infected with a virus.