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, startin g w it h t he
in n ermost 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.
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8. APPENDIX
Technical Notes
Buffer Underrun Protection Function
DVD drives are equipped with a buffer memory that temporarily stores data that
is b ein g t ran sfe rr ed. When th e buff e r m e mo r y becomes empty due to a delay of
data transfer for any reason, a writing error happens. Such a condition is defined
as a buffer underr un ; suc h an e rr or is defined as a buffer underr u n e rr o r.
Buffer underrun protection is featured in this drive.
When a buffer underrun almost happens, buffer underru n protection temporaril y
sus pe nds t he w ri tin g proce ss. Wr i ti n g 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 yo u r co mp ut e r en vi ronment. The included CD/DVD writing software operates
the test writing function that cannot operate when buffer underru n prote ctio n is
activated (default). The buffer underru n protection should be first be deactivated
to use test writing.
DMA
Di rec t M e mo r y A cc e ss ( DM A ), is su p po rt 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, t his is done in the Sys tem
section in the Control Panel where the drive settings are .Please see Section 3.1
above for more information on DMA.
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To en sure the corr ect operation of your new drive, updates to the firmw a re will be made
available as necessary. You c an fin d i nfo rm at io n a bo ut t he mo st rece nt firm w a re for the
drive on the Memorex web site.
URL for the web site is http://www.memorex.com
The m o st rec ent us er su pport i n fo rm a t i o n , i n c l u d i n g f i rm w a re updates, can be found in
the s uppo rt area of Memorex’s web site. Please check this informa t i o n regula rly.
Important Note:
The fir
mwar
e i s co mp le t el y un related to the CD/DVD writing application software.
Packet Writing
This met hod is use d 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 wr itten easil y, pa c k et w ri t in g is p roper 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.
ABOUT THE FIRMWARE
The “ f irm w are” is a small piece of software bu ilt i nt o t he Me mo rex DVD recorder, a nd i s
used to control its basic operation. Since it resides in flash memory, it can be overwritten
and updated.
Important Note:
Ordinary audio CD players can only playback single-session discs or the first
session on a multi-session disc. Do not r
ecord 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 m u lt ip l e
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
in fo rma t io n requ ired 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.
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 prog ram, 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 f ree space available on the disc. A
disc that contains data written in several sessions is defined as a multi-session
disc. A n area that records data and management informa tio n (L ea d-i n/ Le ad -o ut)
is defined as a session. Lead-in and Lead-out are sig nals wr itte n fo r s tati ng t he
starting and ending points of one session.
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