Disk Class Reference

#include <disk.h>

List of all members.

Public Member Functions
	Disk (char *name, VoidFunctionPtr callWhenDone, int callArg)
	~Disk ()
void	ReadRequest (int sectorNumber, char *data)
void	WriteRequest (int sectorNumber, char *data)
void	HandleInterrupt ()
int	ComputeLatency (int newSector, bool writing)

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Constructor & Destructor Documentation

Disk::Disk (  char *  name, VoidFunctionPtr  callWhenDone, int  callArg )

Definition at line 43 of file disk.cc. References ASSERT, DEBUG(), DiskSize, FALSE, Lseek(), MagicNumber, MagicSize, OpenForReadWrite(), OpenForWrite(), Read(), VoidFunctionPtr, and WriteFile(). { int magicNum; int tmp = 0; DEBUG('d', "Initializing the disk, 0x%x 0x%x\n", callWhenDone, callArg); handler = callWhenDone; handlerArg = callArg; lastSector = 0; bufferInit = 0; fileno = OpenForReadWrite(name, FALSE); if (fileno >= 0) { // file exists, check magic number Read(fileno, (char *) &magicNum, MagicSize); ASSERT(magicNum == MagicNumber); } else { // file doesn't exist, create it fileno = OpenForWrite(name); magicNum = MagicNumber; WriteFile(fileno, (char *) &magicNum, MagicSize); // write magic number // need to write at end of file, so that reads will not return EOF Lseek(fileno, DiskSize - sizeof(int), 0); WriteFile(fileno, (char *)&tmp, sizeof(int)); } active = FALSE; }

Disk::~Disk (   )

Definition at line 76 of file disk.cc. References Close(). { Close(fileno); }

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Member Function Documentation

int Disk::ComputeLatency (  int  newSector, bool  writing )

Definition at line 233 of file disk.cc. References DEBUG(), FALSE, RotationTime, stats, and Statistics::totalTicks. Referenced by ReadRequest(), and WriteRequest(). { int rotation; int seek = TimeToSeek(newSector, &rotation); int timeAfter = stats->totalTicks + seek + rotation; #ifndef NOTRACKBUF // turn this on if you don't want the track buffer stuff // check if track buffer applies if ((writing == FALSE) && (seek == 0) && (((timeAfter - bufferInit) / RotationTime) > ModuloDiff(newSector, bufferInit / RotationTime))) { DEBUG('d', "Request latency = %d\n", RotationTime); return RotationTime; // time to transfer sector from the track buffer } #endif rotation += ModuloDiff(newSector, timeAfter / RotationTime) * RotationTime; DEBUG('d', "Request latency = %d\n", seek + rotation + RotationTime); return(seek + rotation + RotationTime); }

void Disk::HandleInterrupt (   )

Definition at line 162 of file disk.cc. References FALSE. { active = FALSE; (*handler)(handlerArg); }

void Disk::ReadRequest (  int  sectorNumber, char *  data )

Definition at line 116 of file disk.cc. References ASSERT, ComputeLatency(), DEBUG(), DebugIsEnabled(), DiskInt, FALSE, interrupt, Lseek(), MagicSize, Statistics::numDiskReads, NumSectors, Read(), Interrupt::Schedule(), SectorSize, stats, and TRUE. { int ticks = ComputeLatency(sectorNumber, FALSE); ASSERT(!active); // only one request at a time ASSERT((sectorNumber >= 0) && (sectorNumber < NumSectors)); DEBUG('d', "Reading from sector %d\n", sectorNumber); Lseek(fileno, SectorSize * sectorNumber + MagicSize, 0); Read(fileno, data, SectorSize); if (DebugIsEnabled('d')) PrintSector(FALSE, sectorNumber, data); active = TRUE; UpdateLast(sectorNumber); stats->numDiskReads++; interrupt->Schedule(DiskDone, (int) this, ticks, DiskInt); }

void Disk::WriteRequest (  int  sectorNumber, char *  data )

Definition at line 136 of file disk.cc. References ASSERT, ComputeLatency(), DEBUG(), DebugIsEnabled(), DiskInt, interrupt, Lseek(), MagicSize, Statistics::numDiskWrites, NumSectors, Interrupt::Schedule(), SectorSize, stats, TRUE, and WriteFile(). { int ticks = ComputeLatency(sectorNumber, TRUE); ASSERT(!active); ASSERT((sectorNumber >= 0) && (sectorNumber < NumSectors)); DEBUG('d', "Writing to sector %d\n", sectorNumber); Lseek(fileno, SectorSize * sectorNumber + MagicSize, 0); WriteFile(fileno, data, SectorSize); if (DebugIsEnabled('d')) PrintSector(TRUE, sectorNumber, data); active = TRUE; UpdateLast(sectorNumber); stats->numDiskWrites++; interrupt->Schedule(DiskDone, (int) this, ticks, DiskInt); }

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The documentation for this class was generated from the following files:

• disk.h
• disk.cc

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