Logical Volume ManagementDSK

Purpose

This IOCtl may be used with any logical volume to which a drive letter has been assigned. This function will be used by FORMAT and will also be of use to those writing disk utilities for OS/2.

Parameter Packet Format

Field                      Length              C Datatype
Command Information        BYTE                UCHAR
Drive Unit                 BYTE                UCHAR
Table Number               WORD                USHORT
LSN                        4 BYTES             ULONG

Command Information

Identify Volume Type
Enable Bad Block Relocation
Disable Bad Block Relocation
Get Bad Block Information
Get Table Size
Get Relocated Sector List
Get Relocated Data
Remove Relocation Table Entry
Clear Relocation Table
Get Drive Name
The Identify Volume Type command provides a way to determine whether a volume is a Compatibility or LVM Volume.
The Enable Bad Block Relocation command enables bad block relocation on the specified volume if that volume supports it.
The Disable Bad Block Relocation command disables bad block relocation on the specified volume.
Get Bad Block Information returns the total number of bad block relocations which are currently in effect for the specified volume, as well as the number of relocation tables being used to perform bad block relocation for the specified volume. There is one bad block relocation table per physical disk partition, so, for LVM volumes employing drive linking, there may be several such tables.
Get Table Size returns the number of active entries in the specified bad block relocation table, as well as the maximum number of entries that the table can hold. The size of a bad block relocation table is dependent upon the size of the partition it is supporting. Larger partitions have larger relocation tables, while smaller partitions have smaller relocation tables.
Get Relocated Sector List returns an array of Logical Sector Numbers (LSN). Each LSN in the array is a sector whose data had to be relocated because of a problem writing to that sector. The array returned is specific to a Relocation Table. The user supplied buffer must be large enough to hold the entire array. The size of the array can be determined by using the Get Table Size command to find the number of active entries in the table, and then multiplying that value by the size of a Logical Sector Number (currently, 4 bytes).
Get Relocated Data returns the data associated with a sector that appears in a relocation table for the specified volume. The user supplied buffer must be at least 512 bytes in length, because 512 bytes are returned.
Remove Relocation Table Entry removes the specified LSN from the relocation tables on the specified volume. This function is typically used by utilities which adjust the file system on a volume so that all LSNs requiring relocation are removed from use. Since the file system will never use these LSNs again, they can be safely removed from the relocation tables for the volume, thereby freeing those entries to be used again.
Clear Relocation Table is used to remove all of the entries in a relocation table in a single operation. This function is intended to be used by FORMAT immediately before a long format is performed. Typically, FORMAT will disable bad block relocation and clear the bad block relocation tables prior to a long format so that all bad sectors may be detected by FORMAT. FORMAT will place any bad sectors detected into the bad block list for the appropriate file system.
Get Drive Name is used to return the user defined name associated with the physical drive on which the specified relocation table resides. This function can be used to identify which physical drive contains a specific relocation table associated with a volume. The name returned will not exceed 20 characters.

Drive Unit is used only when the IOCtl is issued without using a previously allocated file handle. In this case, the IOCtl must be issued with a file handle of 1. Drive Unit values are 0=A, 1=B, 2=C, etc.

Table Number is the number of the relocation table to operate on. This field is not used for commands 0 3, and 6 8.

LSN is the logical sector number of sector requiring relocation. This field is used only by commands 6 and 7.

Data Packet Format

Field                      Length              C DatatypeReturn Value               BYTE                UCHAR
Buffer                     4 BYTEs             void*

Return Value

Return Value is set by every command that this IOCtl accepts. The specific meaning of the value it is set to is dependent upon the command issued.

Buffer is a pointer to an area of memory large enough to hold any return value associated with the command issued. Some commands do not make use of Buffer. For these commands, Buffer should be NULL.

Command Information and possible return values are

Command Information Return Value        Buffer0                   1 = Compatibility V Unused
                    2 = Logical Volume
1                   0 = Success         Unused
                    1 = Failure
2                   0 = Success         Unused
                    1 = Failure
3                   0 = Success         typedef struct_BadBlockInf
                    1 = Failure         ULONG Total_Relocations;
                                        ULONG Total_Tables;
                                        }BadBlockInfo;
4                   0 = Success         typedef struct_BadBlackInf
                    1 = Failure         ULONG Active_Relocations;
                                        ULONG Max_Relocations;
                                        }BadBlockTableInfo;
5                   0 = Success         Array of LSNs.
                    1 = Failure         Each entry in array is
                                        sector requiring relocatio
6                   0 = Success         Data written to
                    1 = Failure         specified sector
7                   0 = Success         Unused
                    1 = Failure
8                   0 = Success         Unused
                    1 = Failure
9                   0 = Success         Text of name being
                    1 = Failure         returned by this function.
                                        Name will be null terminat

Returns

Possible values are shown in the following list

NO_ERROR
ERROR_INVALID_HANDLE
15
31
87
[Back] [Next]