layout_g1_zone.modspec

目前最精确的磁盘模拟器的第3版

# diskmodel (version 1.0)
# Authors: John Bucy, Greg Ganger
# Contributors: John Griffin, Jiri Schindler, Steve Schlosser
#
# Copyright (c) of Carnegie Mellon University, 2001, 2002, 2003.
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MODULE layout_g1_zone
PROTO int dm_layout_g1_zone_loadparams(struct lp_block *b);

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

This specifies the first physical cylinder in the zone.

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

This specifies the last physical cylinder in the zone.

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

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

PARAM Offset of first block		D	1 
DEPEND Blocks per track
# DEPEND Skew units
INIT {
INIT   skew_unit_t skewtmp = NONE;
INIT   if(skew_units != NONE) skewtmp = skew_units;
INIT   else if(layout_skew_units != NONE) skewtmp = layout_skew_units;
INIT   switch(skewtmp) {
INIT   case REVOLUTIONS:
INIT     result->firstblkangle = dm_angle_dtoi(d);
INIT     break;
INIT   case NONE:
INIT   case SECTORS:
INIT   default:
INIT     result->firstblkangle = (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")) { skew_units = REVOLUTIONS; } 
INIT else if(!strcmp(s, "sectors")) { skew_units = 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   skew_unit_t skewtmp = NONE;
INIT   if(skew_units != NONE) skewtmp = skew_units;
INIT   else if(layout_skew_units != NONE) skewtmp = layout_skew_units;
INIT   switch(skewtmp) {
INIT   case REVOLUTIONS:
INIT     result->trackskew = dm_angle_dtoi(d);
INIT     break;
INIT   case NONE:
INIT   case SECTORS:
INIT   default:
INIT     result->trackskew = (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   skew_unit_t skewtmp = NONE;
INIT   if(skew_units != NONE) skewtmp = skew_units;
INIT   else if(layout_skew_units != NONE) skewtmp = layout_skew_units;
INIT   switch(skewtmp) {
INIT   case REVOLUTIONS:
INIT     result->cylskew = dm_angle_dtoi(d);
INIT     break;
INIT   case NONE:
INIT   case SECTORS:
INIT   default:
INIT     result->cylskew = (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.


PARAM Number of spares			I	1 
INIT result->sparecnt = i;

This specifies the number of spare storage locations -- sectors or tracks,
depending on the sparing scheme chosen -- allocated per region of
coverage which may be a track, cylinder, or zone, depending on the
sparing scheme.  For example, if the sparing scheme is 1, indicating
that spare tracks are allocated at the end of the zone, the value of
this parameter indicates how many spare tracks have been allocated for
this zone.

# SLIPBLOCK contains NUM values 
PARAM slips				LIST	1 
TEST !getslips(result, l)

This is a list of lbns for previously detected defective media
locations -- sectors or tracks, depending upon the sparing scheme
chosen -- that were skipped-over or ``slipped'' when the
logical-to-physical mapping was last created.  Each integer in the
list indicates the slipped (defective) location.

# DEFECTBLOCK contains NUM values interpreted as (logphy) pairs
PARAM defects				LIST	1 
TEST !getdefects(result, l)

This list describes previously detected defective media
locations -- sectors or tracks, depending upon the sparing scheme
chosen -- that have been remapped to alternate physical locations.
The elements of the list are interpreted as pairs wherein the first
number is the original (defective) location and the second number
indicates the replacement location.  Note that these locations
will both be either a physical sector number or a physical track
number, depending on the sparing scheme chosen.