Appendix, About the Firmware | Memorex E-IDE guide

9. APPENDIX

Technical Notes

Buffer Underrun Protection Function

DVD drives are equipped with a buffer memory that temporarily stores data that is being transferred. When the buffer memory becomes empty due to a delay of data transfer for any reason, a writing error happens. Such a condition is defined as a buffer underrun; such an error is defined as a buffer underrun error.

Buffer underrun protection is featured in this drive.

When a buffer underrun almost happens, buffer underrun protection temporarily suspends the writing process. Writing resumes when enough data has accumulated in the buffer memory. Buffer Underrun Protection in this

drive is extremely accurate, resulting in seamless recording before and after suspension.

Test Writing

Test writing is a function to check for the possible occurance of buffer underrun in your computer environment. The included CD/DVD writing software operates the test writing function that cannot operate when buffer underrun protection is activated (default). The buffer underrun protection should be first be deactivated to use test writing.

DMA

Direct Memory Access(DMA), is support that allows data transfer between the drives and memory without using the CPU. Both the drives and IDE controller in the machine on the motherboard must include support for DMA. Also, you must manually enable the operating system to support DMA, this is done in the System section in the Control Panel where the drive settings are. See “Important Notes” on page 16 of section 3

Writing Methods

Disc-at-Once (DAO)

This method is used to write all data onto a disc in one operation. It writes multiple pieces of data without placing a space between data, starting with the innermost track of the disc. Once data is written by this method, no data can be added to the same disc even if there is free space available on the disc. This method is useful for making a backup copy of an entire CD or DVD.

Track-at-Once (TAO)

This method is used to write all data on a track-by-track basis. A track can be defined as the smallest unit of area that contains an ordinary program, image file, text file, etc. This method enables you to add data to the same disc, one track of data at a time, as long as there is free space available on the disc. A disc that contains data written in several sessions is defined as a multi-session disc. An area that records data and management information (Lead-in/Lead-out) is defined as a session. Lead-in and Lead-out are signals written for stating the starting and ending points of one session.

Important Note: Ordinary audio CD players can only playback single-session discs or the first session on a multi-session disc. Do not record audio data on the second and subsequent sessions.

Session-at-Once (SAO)

This method is used to write all data on a session-by-session basis. Unlike Track-at-Once described above, Session-at-Once enables you to record multiple tracks onto a disc at at a time. CD EXTRA, for example, uses this method to write multiple pieces of audio data (or multiple tracks) in the first session and information required for computers in the second session. This method enables you to add data into the same disc, one session at a time, as long as there is free space available on the disc. A disc that contains data written in several sessions by this method is defined as a multi-session disc, like a disc written by the Track-at-Once method.

Packet Writing

This method is used to record data onto a disc on a file-by-file basis. This method divides a track into small segments called “packets” so that data can be written on a packet-by-packet basis, which means that you can write data in much the same way as you can copy data to a floppy or hard drive. Since the data can be written easily, packet writing is proper to daily data backup. Packet writing also enables you to add packets to a disc as long as there is free space available on the disc.

9.1. ABOUT THE FIRMWARE

The “firmware” is a small piece of software built into the Memorex DVD recorder, and is used to control its basic operation. Since it resides in flash memory, it can be overwritten and updated.

To ensure the correct operation of your new drive, updates to the firmware will be made available as necessary. You can find information about the most recent firmware for the drive on the Memorex web site.

URL for the web site is http://www.memorex.com

The most recent user support information, including firmware updates, can be found in the support area of Memorex’s web site. Please check this information regularly.

Important Note: The firmware is completely unrelated to the CD/DVD writing application software.