Write a UDF CDR

• Download demo project - 238 Kb

Introduction

Some electronic devices need to use CDR as storage media, and you have to append several files each time before the space is used out. In this case, UDF is a good solution, since for each writing, only 7 logic blocks of overhead are used. (Multisession CDs use several minutes for each session's leadout)

How to use the demo

(You need WNASPI32.dll to run the demo, which could be downloaded from Ahead.)

• Select the CDR drive you want to write to.
• Insert a blank disc, "Format" it.
• Browse to select files, and write to the disc. (Now you can view the files using DirectCD).
• You can list the content of the CDR, and restore files to hard disk
• Close Session, now any CD drive can read it..

How to use the source code

//Create a variable for your drive
SCSI2 m_drive;
//m_HA:HostAdpaterNumber,m_ID:SCSI ID,m_LUN:LogicUnitNumber
m_drive.SCSISelectDevice(m_HA,m_ID,m_LUN);
//For a blank CDR, you need to format it 
m_drive.FormatDisc("VOL1");
//Then you can write files onto it
m_drive.WriteFiles("Test1.bmp");
//Append more files here...
//
//After you have writen ALL the files, close the session
m_drive.CloseSession();
//Now it's readable by regular CDROM drive.

Some useful functions

SCSIRead()      //Read data from CDR
WritePacket()      //Write packets to CDR
ReadTrackInfo()      //Read track info, like next writable address
ReadDiskInfo()      //Read disc info, like capacity
TestUnitReady()      //See if the drive is ready
LoadUnload()      //Eject/Close the tray
SetWriteParameters()    //Set write mode
SCSISetSpeed()      //Set read/write speed
ListFiles()      //List files on the CDR
SaveFileAs()      //Save file on CDR to hard disk

If you want to know more inside stuff

Things you need to have:

• SCSI command block structure (ANSI X3.131-1994)
• SCSI multimedia commands-2 (ANSI NCITS 333-2000)
• OSTA specs: ECMA-167, Universal Disk Format Specification, ECMA-119

Things you need to know:

• SCSI2 block command structure
• Use of ASPI
• Concepts about CDR: track, session, logical blocks, PMA, ATIP, TOC, write modes...
• UDF(Volume structure, file system)

More info at my website.

Revision History

• Ver 1.01
  • More comments, some code clean up
  • New function: ListFiles()
  • New function: SaveFileAs()
• Ver 1.02
  • Some changes on the demo application