288 lines
8.2 KiB
C
288 lines
8.2 KiB
C
/*++
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Copyright (C) Microsoft Corporation, 1992 - 1998
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Module Name:
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physlogi.c
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Abstract:
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This module contains functions used specifically by tape drivers.
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It contains functions that do physical to pseudo-logical and pseudo-
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logical to physical tape block address/position translation.
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Environment:
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kernel mode only
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Revision History:
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--*/
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#include "ntddk.h"
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#include "physlogi.h"
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(PAGE, TapeClassPhysicalBlockToLogicalBlock)
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#pragma alloc_text(PAGE, TapeClassLogicalBlockToPhysicalBlock)
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#endif
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//
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// defines for various QIC physical tape format constants
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//
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#define QIC_150_BOT_OFFSET 2
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#define QIC_525_PSEUDO_PHYSICAL_BLOCK_SIZE 512
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#define QIC_525_PHYSICAL_BLOCK_SIZE 1024
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#define QIC_525_DATA_BLKS_PER_FRAME 14
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#define QIC_525_ECC_BLKS_PER_FRAME 2
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#define QIC_525_BLKS_PER_FRAME 16
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#define QIC_525_BOT_OFFSET 16
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#define QIC_1350_PHYSICAL_BLOCK_SIZE 512
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#define QIC_1350_DATA_BLKS_PER_FRAME 52
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#define QIC_1350_ECC_BLKS_PER_FRAME 12
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#define QIC_1350_BLKS_PER_FRAME 64
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#define QIC_1350_BOT_OFFSET 64
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ULONG
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TapeClassPhysicalBlockToLogicalBlock(
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IN UCHAR DensityCode,
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IN ULONG PhysicalBlockAddress,
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IN ULONG BlockLength,
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IN BOOLEAN FromBOT
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)
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/*++
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Routine Description:
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This routine will translate from a QIC physical tape format
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specific physical/absolute block address to a pseudo-logical
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block address.
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Arguments:
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DensityCode // tape media density code
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PhysicalBlockAddress // tape format specific tape block address
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BlockLength // mode select/sense block length setting
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FromBOT // true/false - translate from BOT
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Return Value:
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ULONG
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--*/
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{
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ULONG logicalBlockAddress;
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ULONG frames;
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PAGED_CODE();
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logicalBlockAddress = PhysicalBlockAddress;
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switch ( DensityCode ) {
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case 0:
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logicalBlockAddress = 0xFFFFFFFF;
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break;
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case QIC_24:
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logicalBlockAddress--;
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break;
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case QIC_120:
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logicalBlockAddress--;
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break;
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case QIC_150:
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if (FromBOT) {
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if (logicalBlockAddress > QIC_150_BOT_OFFSET) {
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logicalBlockAddress -= QIC_150_BOT_OFFSET;
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} else {
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logicalBlockAddress = 0;
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}
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} else {
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logicalBlockAddress--;
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}
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break;
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case QIC_525:
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case QIC_1000:
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case QIC_2GB:
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if (FromBOT && (logicalBlockAddress >= QIC_525_BOT_OFFSET)) {
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logicalBlockAddress -= QIC_525_BOT_OFFSET;
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}
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if (logicalBlockAddress != 0) {
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frames = logicalBlockAddress/QIC_525_BLKS_PER_FRAME;
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logicalBlockAddress -= QIC_525_ECC_BLKS_PER_FRAME*frames;
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switch (BlockLength) {
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case QIC_525_PHYSICAL_BLOCK_SIZE:
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break;
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case QIC_525_PSEUDO_PHYSICAL_BLOCK_SIZE:
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logicalBlockAddress *= 2;
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break;
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default:
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if (BlockLength > QIC_525_PHYSICAL_BLOCK_SIZE) {
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if ((BlockLength%QIC_525_PHYSICAL_BLOCK_SIZE) == 0) {
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logicalBlockAddress /=
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BlockLength/QIC_525_PHYSICAL_BLOCK_SIZE;
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} else {
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logicalBlockAddress /=
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1+(BlockLength/QIC_525_PHYSICAL_BLOCK_SIZE);
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}
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}
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break;
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}
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}
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break;
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case QIC_1350:
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case QIC_2100:
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if (FromBOT && (logicalBlockAddress >= QIC_1350_BOT_OFFSET)) {
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logicalBlockAddress -= QIC_1350_BOT_OFFSET;
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}
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if (logicalBlockAddress != 0) {
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frames = logicalBlockAddress/QIC_1350_BLKS_PER_FRAME;
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logicalBlockAddress -= QIC_1350_ECC_BLKS_PER_FRAME*frames;
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if (BlockLength > QIC_1350_PHYSICAL_BLOCK_SIZE) {
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if ((BlockLength%QIC_1350_PHYSICAL_BLOCK_SIZE) == 0) {
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logicalBlockAddress /=
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BlockLength/QIC_1350_PHYSICAL_BLOCK_SIZE;
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} else {
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logicalBlockAddress /=
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1+(BlockLength/QIC_1350_PHYSICAL_BLOCK_SIZE);
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}
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}
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}
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break;
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}
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return logicalBlockAddress;
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} // end TapeClassPhysicalBlockToLogicalBlock()
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TAPE_PHYS_POSITION
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TapeClassLogicalBlockToPhysicalBlock(
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IN UCHAR DensityCode,
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IN ULONG LogicalBlockAddress,
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IN ULONG BlockLength,
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IN BOOLEAN FromBOT
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)
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/*++
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Routine Description:
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This routine will translate from a pseudo-logical block address
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to a QIC physical tape format specific physical/absolute block
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address and (space) block delta.
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Arguments:
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DensityCode // tape media density code
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LogicalBlockAddress // pseudo-logical tape block address
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BlockLength // mode select/sense block length setting
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FromBOT // true/false - translate from BOT
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Return Value:
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TAPE_PHYS_POSITION info/structure
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--*/
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{
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TAPE_PHYS_POSITION physPosition;
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ULONG physicalBlockAddress;
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ULONG remainder = 0;
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ULONG frames;
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PAGED_CODE();
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physicalBlockAddress = LogicalBlockAddress;
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switch ( DensityCode ) {
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case 0:
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physicalBlockAddress = 0xFFFFFFFF;
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break;
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case QIC_24:
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physicalBlockAddress++;
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break;
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case QIC_120:
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physicalBlockAddress++;
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break;
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case QIC_150:
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if (FromBOT) {
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physicalBlockAddress += QIC_150_BOT_OFFSET;
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} else {
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physicalBlockAddress++;
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}
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break;
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case QIC_525:
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case QIC_1000:
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case QIC_2GB:
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if (physicalBlockAddress != 0) {
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switch (BlockLength) {
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case QIC_525_PHYSICAL_BLOCK_SIZE:
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break;
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case QIC_525_PSEUDO_PHYSICAL_BLOCK_SIZE:
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remainder = physicalBlockAddress & 0x00000001;
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physicalBlockAddress >>= 1;
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break;
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default:
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if (BlockLength > QIC_525_PHYSICAL_BLOCK_SIZE) {
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if ((BlockLength%QIC_525_PHYSICAL_BLOCK_SIZE) == 0) {
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physicalBlockAddress *=
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BlockLength/QIC_525_PHYSICAL_BLOCK_SIZE;
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} else {
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physicalBlockAddress *=
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1+(BlockLength/QIC_525_PHYSICAL_BLOCK_SIZE);
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}
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}
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break;
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}
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frames = physicalBlockAddress/QIC_525_DATA_BLKS_PER_FRAME;
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physicalBlockAddress += QIC_525_ECC_BLKS_PER_FRAME*frames;
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}
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if (FromBOT) {
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physicalBlockAddress += QIC_525_BOT_OFFSET;
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}
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break;
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case QIC_1350:
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case QIC_2100:
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if (physicalBlockAddress != 0) {
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if (BlockLength > QIC_1350_PHYSICAL_BLOCK_SIZE) {
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if ((BlockLength%QIC_1350_PHYSICAL_BLOCK_SIZE) == 0) {
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physicalBlockAddress *=
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BlockLength/QIC_1350_PHYSICAL_BLOCK_SIZE;
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} else {
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physicalBlockAddress *=
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1+(BlockLength/QIC_1350_PHYSICAL_BLOCK_SIZE);
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}
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}
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frames = physicalBlockAddress/QIC_1350_DATA_BLKS_PER_FRAME;
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physicalBlockAddress += QIC_1350_ECC_BLKS_PER_FRAME*frames;
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}
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if (FromBOT) {
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physicalBlockAddress += QIC_1350_BOT_OFFSET;
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}
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break;
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}
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physPosition.SeekBlockAddress = physicalBlockAddress;
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physPosition.SpaceBlockCount = remainder;
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return physPosition;
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} // end TapeClassLogicalBlockToPhysicalBlock()
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