Method of disk formatting

Details Method of disk formatting Method of disk formatting

1999-03-29

2001-05-15

Faber, Alan T. (Department: 2651)

Dynamic magnetic information storage or retrieval

General processing of a digital signal

Data in specific format

C707S793000

Reexamination Certificate

active

06233105

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a disk drive system, and more particularly to a method for quickly formatting a disk.
A typical computer system includes a microprocessor, a memory and various peripherals. The disk drive is one of the peripherals for storing operating system files, application programs, data files and, in general, any information that user wishes to save for subsequent access. Both hard disk and floppy disk require the step of doing a start-up process before using the disk. The start-up process is called formatting. Currently, under the DOS and Windows environments, the formatting process is done by the “format” command that provided by Microsoft Company. The disk is divided and numbered into Sectors and Tracks, then the information about the Sectors and Tracks is written into the FAT and file directory that are previously built therein.
FIG. 1
is a partition
10
structure diagram including a boot record
11
, a first FAT
12
, a second FAT
13
, a file directory
14
and a data record area
15
. Where file directory
14
consists of many file directory items
141
to store and provide the message about the data which stored in the data record area
15
such as file name, extension file name, creation time and etc. Using the format command to format a disk is time-consuming; for example, it needs 20 minute to format a 3 gaga-byte hard disk. Although Microsoft has provided a quick formatting command “format/q”, it can be used only in the condition that the disk is unnecessary to be completely formatted (i.e. the disk has been formatted before) and besides not in the conditions listed below:
1. The disk is low level formatted.
2. The disk is repartitioned.
3. The disk has bad sectors.
The format command that Microsoft provided is time-consuming and the quick format command is restricted to particular conditions of the disk such as the disk is not low level formatted or the disk is not repartitioned and etc. It means that the quick format command “format/q” is work only for a disk that is formatted and had no bad sectors, not suites for any disks' formatting.
SUMMARY OF INVENTION
This invention is providing a method to format a disk (or disk partition) quickly, and it works on the conditions when the disk is only low level formatted, repartitioned and even has bad sector(s) thereon.
The technique of this invention is performing the interrupt INT 13h of the BIOS to get disk's parameters including the total sector number of disk (or disk partition), the location of the boot record, the type of disk and the number of disk that is needed when formatting, and then recalculate the disk sectors by a logic operation unit, rewrite the result into the boot record of the original disk (or disk partition). The structure of the boot record consists of five parts as follows
1. Jump Instruction, 3 bytes.
2. OEM names, 8 bytes.
3. DPB, which is different between FAT 16 and FAT 32.
4.Bootstrap code, is a starting procedure, it duplicates the IO.dos and command.com after disk is formatted so that the computer can be startup.
5.End with 5 5 aa
In accordance with the structure described above the disc properties block (DPB) is different between FAT16 and FAT32 but the other parts are the same and fixed. Table 1 and table 2 are structures of the DPB of FAT16 and FAT32 respectively. The major technique of this invention is the calculation of DPB. Referring to table 1 and table 2, it is obvious that the data of DPB has many differences between FAT16 and FAT32; for example, the maximum file directory item of FAT16 is 0x002 but is 0 in FAT32. After the interrupt INT 13h of BIOS is performed, the disk parameter was read out and equation (1):
sfat=(stotal 0x21)/(1+s*0x100)+1
and equation (2):
sfat=(stotal 0x23)/(1+8*0x080)+1
are used to calculate the sector number of every FAT in the logic operation unit, then the number is written into the mapped place in the boot record and the FAT and file directory are cleared to zero and the media number is written into starting place of FAT.
It is necessary to notice that there are three boot records in the FAT32 system, the first one is the DPB which is similar to the FAT16 system, the second one records the size of free space, if the unit is the cluster of the portion, which is equal to (stotal 2*sfat 0x20)/8−1 and the third one is the bootstrap code which won't affect the calculation.
TABLE 1
DPB structure of FAT16 system, located at the 0Bth byte of the first
sector of the disk partition
Location
Contents
0B-0C
Bytes per sector (0x0002 = 512)
0D
Sectors per cluster (decide by size of partition)
0E-0F
Reserved (0x0100)
10
Number of FAT (0x02)
11-12
Maximum number of file directory items (0x0002)
13-14
Total sectors (0, maximum is 65535)
15
Media description code (0xf8)
16-17
Sectors per FAT (equation 1)
18-19
Sectors per track
1A-1B
Head number
1C-1D
Hidden sectors (no influence to the result)
20-23
Total sector number if byte 13-14 is 0
24
Physical drive number (first = 0x80, second = 0x81)
25
Reserved
26
Characteristic byte of extension index record (0x29)
27-2A
Serial number of disk (generate randomly)
2B-35
Label (11 bytes)
36-3D
File system type (FAT16)
TABLE 2
DPB structure of FAT32 system, located at the 0Bth byte of the first
sector of the disk partition
Location
Contents
0B-0C
Bytes per ecotr (0x0002 = 512)
0D
Sectors per cluster (decide by size of partition)
0E-0F
Reserved (0x0100)
10
Number of FAT (0x02)
11-12
Maximum number of file directory items (0)
13-14
Total sectors (0)
15
Media description code (0xf8)
16-17
Sectors per FAT (0)
18-19
Sectors per track
1A-1B
Head number
1C-1F
Hidden sectors (no influence to the result)
20-23
Total sector number if byte 13-14 is 0
24-27
Sector per FAT (equation 2)
28-29
File system Ver. (major) (0)
2A-2B
File system Ver. (minor) (0)
2C-2D
Number of file directories first cluster (0x02000)
2E-2F
High bytes of the file directory s first cluster
30-31
FSINFO Sector number (0xffff if not exist)
32-33
Backup boot sectors (0xffff if not exist)
34-3F
Reserved
40
Physical drive number (first = 0x80, second = 0x81)
41
Reserved
42
Characteristic byte of extension index record (0x29)
43-46
Serial number of disk (generate randomly)
47-51
Label (11 bytes)
52-59
File system type (FAT32)


REFERENCES:
patent: 5873118 (1999-02-01), Letwin

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