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3-8-1] How well do 80-minute CD-R blanks work?


This article is from the CD-Recordable FAQ, by Andy McFadden (fadden@fadden.com) with numerous contributions by others.

3-8-1] How well do 80-minute CD-R blanks work?


In general, they work just fine. Reports from people who have used
80-minute CD-Rs indicate that compatibility with different CD-ROM drives is
very good. However, bear in mind the following statement, which was sent
by e-mail from a TDK representative:

"The CD-R80 is a special product developed by TDK to meet the application
needs of software developers and music studios. To achieve its 80 minute
recording time, track pitch and scanning velocity specification tolerances
had to be minimized, reducing the margin of error between drive and media.
This means limited compatibility between some CD-Recorders and CD-ROM
Readers. If you intend to use this recording length, please check with
your hardware manufacturer. Use of the CD-R80 is at one's own risk. No
guarantees of performance are made by TDK."

Whether it's better to use 80-minute discs or "overburning" (described in
the next section) is a worthy subject for debate. Both can cause problems
on different CD-ROM drives, and not all recorders are capable of doing one
or the other. Because of consumer demand, all recent drives can do both.

An 80-minute disc has roughly 360,000 sectors instead of the 333,000
defined by the Red Book standard. This increases the CD-ROM capacity
from 650MB to 703MB.

Here's a few personal notes on my experiments with TDK 80-minute "green"
blanks, back in late 1997. Back then it was hard to find 80-minute
discs and easy to find 74-minute discs; these days the situation has
reversed itself. I was able to purchase a small quantity (three discs)
from Microboards at http://www.microboards.com/. This section is rather
outdated now, but I'm leaving it in as a historical footnote.

The discs were part number SCWA-ETC80A-X, priced at US$40.00 per disc in
October 1997. That was about 20x the cost for an extra 8% storage. The
discs were unbranded. The only difference I could see between these and
other TDK green discs is that on the hub it says "CD-Recordable 6129B-80".
Easy CD Creator Deluxe v3 showed 359,624 blocks (702.8MB in MODE-1) on the
TDK 80-minute blanks, versus 333,010 blocks (650.8MB) available on my
Mitsui gold 74-minute blanks.

The first challenge was finding software that would work correctly with the
discs. Neither Easy-CD Pro 95 v1.2 nor Easy CD Creator Deluxe v3.0 would
allow me to do a test recording with more than 650MB of files. I ended up
using mkisofs to create an image file with 341,163 blocks (666.3MB) of
data, composed of two large .AVI files, and three smaller pieces of one of
the other .AVI files. (With Easy CD Creator Deluxe v3.5 and later, you
can choose to ignore a warning about the data size.)

Using a Yamaha CDR-102 with v1.0 firmware, the first thing I tried was to
burn the image file to a 74-minute blank. Easy-CD immediately rejected the
disc, saying there wasn't enough space. I then put the 80-minute blank in
and did a test run. Easy-CD Pro 95 had no problems burning the ISO-9660
image file, until the screen saver activated and McAfee anti-virus "screen
scan" kicked in. Good thing it was a test burn; I got a buffer underrun.
I killed the screen saver and virus checker and ran again, had a successful
test run, and followed it with a successful burn.

To verify the data, I used Easy-CD Pro 95's "compare track" feature. This
failed, complaining that one track was shorter than the other. My guess is
that the compare feature has some sort of track length limitation. My next
attempt was to use the Linux "sum" command to make sure that the disc was
readable in my Plextor 8Plex. This worked fine, and the output of "sum"
matched what I got on the 4x CD-ROM drive in the Sun workstation at work.
I also tried the disc in a Mac 7500 and a Dell Pentium, and had no problems
with either.

The next step was an 80-minute audio CD, and that's where things fell
apart. Easy-CD Pro 95 v1.2 didn't work at all (!), Easy CD Creator Deluxe
v3.0 again refused to allow me to create a long audio CD, and with Jeff
Arnold's software (both the DOS version and CDRWIN) the test write failed
after a minute or so (after the lead-in had completed?). Strangely,
removing the last two tracks from the cue sheet, which reduced it to 72
minutes, allowed the test write to succeed on both 74-minute and 80-minute
blanks. It appears that the Yamaha CDR-102 drive is unwilling to write
that much audio data.


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