com.webcodepro.applecommander.storage.physical
Class ImageOrder

java.lang.Object
  com.webcodepro.applecommander.storage.physical.ImageOrder

Direct Known Subclasses:

DosOrder, ProdosOrder

public abstract class ImageOrder
extends java.lang.Object

Manages the interface between the physical disk image order and the logical operating system specific order. These management objects are intended to be hidden by Disk itself, although the ImageOrder may be changed (overridden).

To implement this class, over-ride the block-oriented methods (readBlock, writeBlock) or the track and sector-oriented methods (readSector, writeSector). Ensure that isBlockDevice or isTrackAndSectorDevice is set appropriately.

Note that a block is generally assumed to be an Apple ProDOS (or Apple Pascal) formatted volume where a block is 512 bytes. The track and sector device is generally a 140K 5.25" disk, although it may be an 800K 3.5" disk with two 400K DOS volumes. In either case, the sector size will be 256 bytes.

At this time, the RDOS block of 256 bytes is managed by the RdosFormatDisk, and the 1024 byte CP/M block is managed by the CpmFormatDisk (the CP/M sector of 128 bytes is largely ignored).

Design note: The physical order could alternatively be implemented with a BlockPhysicalOrder structure which includes ProdosOrder and a Track and Sector adapter, as well as a TrackAndSectorPhysicalOrder which includes a NibblePhysicalOrder and DosOrder as well as a Block adapter class. This way, Disk contains two separate classes (block as well as a track/sector) to manage the disk.

Author:

Rob Greene (RobGreene@users.sourceforge.net)

Constructor Summary

ImageOrder(ByteArrayImageLayout diskImageManager)
Construct a ImageOrder.

Method Summary

void	format() Format the media.
int	getBlocksOnDevice() Answer with the number of blocks on this device.
ByteArrayImageLayout	getDiskImageManager() Get the physical disk image.
int	getPhysicalSize() Answer with the physical size of this disk volume.
int	getSectorsPerDisk() Answer with the total number of sectors in a disk.
int	getSectorsPerTrack() Answer with the number of sectors per track on this device.
int	getTracksPerDisk() Answer with the number of tracks on this device.
abstract boolean	isBlockDevice() Indicates that this device is block ordered.
boolean	isSizeApprox(int value) Indicates if the physical disk is approximately this size.
abstract boolean	isTrackAndSectorDevice() Indicates that this device is track and sector ordered.
abstract byte[]	readBlock(int block) Read the block from the disk image.
byte[]	readBytes(int start, int length) Extract a portion of the disk image.
abstract byte[]	readSector(int track, int sector) Retrieve the specified sector.
void	setDiskImageManager(ByteArrayImageLayout diskImageManager) Set the physical disk image.
abstract void	writeBlock(int block, byte[] data) Write the block to the disk image.
void	writeBytes(int start, byte[] bytes) Write data to the disk image.
abstract void	writeSector(int track, int sector, byte[] bytes) Write the specified sector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ImageOrder

public ImageOrder(ByteArrayImageLayout diskImageManager)

Construct a ImageOrder.

Method Detail

getDiskImageManager

public ByteArrayImageLayout getDiskImageManager()

Get the physical disk image.

getPhysicalSize

public int getPhysicalSize()

Answer with the physical size of this disk volume.

setDiskImageManager

public void setDiskImageManager(ByteArrayImageLayout diskImageManager)

Set the physical disk image.

readBytes

public byte[] readBytes(int start,
                        int length)

Extract a portion of the disk image.

writeBytes

public void writeBytes(int start,
                       byte[] bytes)

Write data to the disk image.

getBlocksOnDevice

public int getBlocksOnDevice()

Answer with the number of blocks on this device.

readBlock

public abstract byte[] readBlock(int block)

Read the block from the disk image.

writeBlock

public abstract void writeBlock(int block,
                                byte[] data)

Write the block to the disk image.

isBlockDevice

public abstract boolean isBlockDevice()

Indicates that this device is block ordered.

isTrackAndSectorDevice

public abstract boolean isTrackAndSectorDevice()

Indicates that this device is track and sector ordered.

getTracksPerDisk

public int getTracksPerDisk()

Answer with the number of tracks on this device.

getSectorsPerTrack

public int getSectorsPerTrack()

Answer with the number of sectors per track on this device.

readSector

public abstract byte[] readSector(int track,
                                  int sector)
                           throws java.lang.IllegalArgumentException

Retrieve the specified sector.

Throws:

java.lang.IllegalArgumentException

writeSector

public abstract void writeSector(int track,
                                 int sector,
                                 byte[] bytes)
                          throws java.lang.IllegalArgumentException

Write the specified sector.

Throws:

java.lang.IllegalArgumentException

isSizeApprox

public boolean isSizeApprox(int value)

Indicates if the physical disk is approximately this size. Currently hardcoded to allow up to 10 extra bytes at the end of a disk image. Must be at least the requested size!

format

public void format()

Format the media. Formatting at the ImageOrder level deals with low-level issues. A typical ordering just needs to have the image "wiped," and that is the assumed implementation. However, specialized orders - such as a nibbilized disk - need to lay down track and sector markers.

getSectorsPerDisk

public int getSectorsPerDisk()

Answer with the total number of sectors in a disk. This is used to size the disk and compare sizes instead of using byte counts which can differ.