-- MarkerPage.mesa (last edited by: Luniewski on: July 24, 1980 9:04 AM)

DIRECTORY

DiskChannel USING [Drive],

Environment USING [wordsPerPage],

File USING[ID],

LogicalVolume USING [Handle, LogicalSubvolumeMarker],

PhysicalVolume USING [ID],

PhysicalVolumeFormat USING [Handle, PhysicalSubvolumeMarker];

MarkerPage: DEFINITIONS =

BEGIN

-- SubVolumeMarkerPage is set up to occupy a full page, with each half taking half of the page. This allows each part to grow independently. This may not win much in the long run, but it is cheap ti implement.

SubVolumeMarkerPage: TYPE = MACHINE DEPENDENT RECORD[

logical: LogicalVolume.LogicalSubvolumeMarker,

fill1: ARRAY SubVolumeFill1 OF WORD ← NULL,

physical: PhysicalVolumeFormat.PhysicalSubvolumeMarker,

fill2: ARRAY SubVolumeFill2 OF WORD ← NULL,

checksum: CARDINAL ← 0];

CacheKey: TYPE = RECORD[SELECT type:* FROM

drive =>[h: DiskChannel.Drive],

physicalID =>[id: PhysicalVolume.ID],

ENDCASE ];

-- Procedures implemented in MarkerPageImpl

CreateMarkerPage: PROCEDURE[pvHandle: PhysicalVolumeFormat.Handle, lvHandle: LogicalVolume.Handle, physicalSubvolumeNumber: CARDINAL];

UpdateLogicalMarkerPages: PROCEDURE[lvHandle: LogicalVolume.Handle];

UpdatePhysicalMarkerPages: PROCEDURE[pvHandle: PhysicalVolumeFormat.Handle];

Enter: PROCEDURE[drive: DiskChannel.Drive, physicalID: PhysicalVolume.ID];

EnterMarkerID: PROCEDURE[c: CacheKey, markerID: File.ID];

GetNextPhysicalVolume: PROCEDURE[thisPvID: PhysicalVolume.ID] RETURNS [nextPvID: PhysicalVolume.ID, drive: DiskChannel.Drive];

-- Find is exported because some of Special Volume operations use it.

Find: PROCEDURE[CacheKey] RETURNS [drive: DiskChannel.Drive, physicalID: POINTER TO READONLY PhysicalVolume.ID, markerID: POINTER TO READONLY File.ID];

NotFound: ERROR;

Flush: PROCEDURE[CacheKey];

-- Constants

SubVolumeFill1: TYPE = [SIZE[LogicalVolume.LogicalSubvolumeMarker]..Environment.wordsPerPage/2);

SubVolumeFill2: TYPE = [Environment.wordsPerPage/2+SIZE[PhysicalVolumeFormat.PhysicalSubvolumeMarker]..Environment.wordsPerPage-1);

-- Assertion

SubVolumeMarkerSize: CARDINAL[Environment.wordsPerPage..Environment.wordsPerPage] = SIZE[SubVolumeMarkerPage];

END.......

LOG

Time: October 1, 1979 12:20 PMBy: ForrestAction: Created from old code in volumeImpl.mesa

Time: May 20, 1980 2:50 PMBy: LuniewskiAction: PhysicalVolume => PhysicalVolumeFormat

Time: July 24, 1980 9:04 AMBy: LuniewskiAction: Added GetNextPhysicalVolume.