layout_g2_zone.modspec

来自「disksim是一个非常优秀的磁盘仿真工具」· MODSPEC 代码 · 共 123 行

MODULE layout_g2_zone
HEADER \#include "../layout_g2.h"
RESTYPE struct dm_layout_g2_zone *
PROTO int dm_layout_g2_zone_loadparams(struct lp_block *b);

PARAM First cylinder number		I	1 
TEST i >= 0
INIT result->cyllow = i;

This specifies the first physical cylinder in the zone.

PARAM Last cylinder number		I	1  
TEST i >= 0
INIT result->cylhigh = i;

This specifies the last physical cylinder in the zone.
	
PARAM First LBN				I	1
TEST i >= 0
INIT result->lbnlow = i;

The first LBN in this zone.

PARAM Last LBN				I	1
TEST i >= 0
INIT result->lbnhigh = i;

The first LBN in this zone.


PARAM Blocks per track			I	1  
TEST i > 0
INIT result->st = i;
INIT result->sector_width = (dm_angle_t)(((long long)1 << 32) / result->st);

This specifies the number of sectors (independent of logical-to-physical
mappings) on each physical track in the zone.

 
PARAM Zone Skew				D	0
DEPEND Blocks per track
# DEPEND Skew units
INIT {
INIT   switch(result->skew_units) {
INIT   case DM_SU_REVOLUTIONS:
INIT     result->zskew = dm_angle_dtoi(d);
INIT     break;
INIT   case DM_SU_SECTORS:
INIT   default:
INIT     result->zskew = (int)d * result->sector_width;
INIT     break;
INIT   }
INIT }

This specifies the physical offset of the first logical sector in the
zone.  Physical sector 0 of every track is assumed to begin at the
same angle of rotation.  This may be in either sectors or revolutions
according to the ''Skew units'' parameter.


PARAM Skew units			S	0 
INIT if(!strcmp(s, "revolutions")) { result->skew_units = DM_SU_REVOLUTIONS; } 
INIT else if(!strcmp(s, "sectors")) { result->skew_units = DM_SU_SECTORS; }
INIT else { ddbg_assert(0); }

Default is \texttt{sectors}.  This value overrides any set in the
surrounding layout block.


#PARAM Empty space at zone front		I	1 
#INIT result->deadspace = i;

#This specifies the size of the ``management area'' allocated at the
#beginning of the zone for internal data structures.  This area can not
#be accessed during normal activity and is not part of the disk's
#logical-to-physical mapping.


PARAM Skew for track switch		D	0 
DEPEND Blocks per track

INIT {
INIT   switch(result->skew_units) {
INIT   case DM_SU_REVOLUTIONS:
INIT     result->hsskew = dm_angle_dtoi(d);
INIT     break;
INIT   case DM_SU_SECTORS:
INIT   default:
INIT     result->hsskew = (int)d * result->sector_width;
INIT     break;
INIT   }
INIT }

This specifies the number of physical sectors that are skipped when
assigning logical block numbers to physical sectors at a track
crossing point.  Track skew is computed by the manufacturer to
optimize sequential access. This may be in either sectors or
revolutions according to the ''Skew units'' parameter.

 
PARAM Skew for cylinder switch		D	0 
DEPEND Blocks per track
INIT {
INIT   switch(result->skew_units) {
INIT   case DM_SU_REVOLUTIONS:
INIT     result->csskew = dm_angle_dtoi(d);
INIT     break;
INIT   case DM_SU_SECTORS:
INIT   default:
INIT     result->csskew = (int)d * result->sector_width;
INIT     break;
INIT   }
INIT }

This specifies the number of physical sectors that are skipped when
assigning logical block numbers to physical sectors at a cylinder
crossing point.  Cylinder skew is computed by the manufacturer to
optimize sequential access. This may be in either sectors or
revolutions according to the ''Skew units'' parameter.