═══ 1. LVM Constants (lvm_cons.h) ═══

Module: lvm_cons.h

Description 

This module defines constants used throughout the LVM code.


═══ 1.1. Constants ═══

The following sections describe constants defined in lvm_cons.h. 


═══ 1.1.1. Disk geometry constants ═══

The number of bytes in a sector on the disk. 

#define BYTES_PER_SECTOR  512

The maximum number of cylinders, heads, and sectors that a partition table 
entry can accomodate. 

Cylinders are numbered 0 - 1023, for a maximum of 1024 cylinders. 
Heads are numbered 0 - 255, for a maximum of 256 heads. 
Sectors are numbered 1 - 63, for a maximum of 63 sectors per track. 

#define MAX_CYLINDERS 1024
#define MAX_HEADS     256
#define MAX_SECTORS   63


═══ 1.1.2. Extended Boot Record constants ═══

The following define the values used to indicate that a partition table entry 
is for an EBR, not a partition. 

#define EBR_BOOT_INDICATOR     0
#define EBR_FORMAT_INDICATOR   5


═══ 1.1.3. Default indicator value constants ═══

The following define is used as the default Format_Indicator for new 
non-primary partitions. 

#define NEW_LOGICAL_DRIVE_FORMAT_INDICATOR   0x6

The following define is used as the default Format_Indicator for a new 
non-active primary partitions. 

#define NEW_PRIMARY_PARTITION_FORMAT_INDICATOR   0x16

The following define is used as the default Format_Indicator for a new active 
primary partition. 

#define NEW_ACTIVE_PRIMARY_PARTITION_FORMAT_INDICATOR  0x06

The following define is used to hold the value of the Boot_Indicator for active 
partitions. 

#define ACTIVE_PARTITION   0x80


═══ 1.1.4. Name length constants ═══

(These length constants do not include null terminators.) 

Define the size of a Partition Name.  Partition Names are user defined names 
given to a partition. 

#define PARTITION_NAME_SIZE  20

Define the size of a volume name.  Volume Names are user defined names given to 
a volume. 

#define VOLUME_NAME_SIZE  20

Define the size of a disk name.  Disk Names are user defined names given to 
physical disk drives in the system. 

#define DISK_NAME_SIZE    20

The name of the filesystem in use on a partition.  This name may be up to 12 ( 
+ NULL terminator) characters long. 

#define FILESYSTEM_NAME_SIZE 20


═══ 1.1.5. Miscellaneous constants ═══

The comment field is reserved but is not currently used.  This is for future 
expansion and use. 

#define COMMENT_SIZE 81

Define the minimum number of sectors to reserve on the disk for Boot Manager. 

#define BOOT_MANAGER_SIZE   2048