Q. What is the resolution of the graph?

A. The Y-axis of the graph (disc location) is fixed to 5 samples per minute of CD time.  For an 80-minute disc there are 400 separate samples.  Each sample is the average of the time for all 900 sectors that it represents.  The X-axis resolution (speed) resolution depends on the highest speed shown on the graph.

Q. What do upward spikes (faster) in the graph mean?

A. An upward spike indicates the writer buffer could “suddenly” hold more data.  There are a number of reasons why this happens:

• An upward spike at the beginning shows only the drive buffer being filled initially.  This is normal behavior for some writers.  This should be consistent for all writers of this model.
• TimeWrite was delayed by Windows for some reason.  This will generally not be exactly reproducible, but will show up as a random factor.
• The drive’s buffer management has some inconsistencies in it which cause this.  If you see many upward spikes and they are consistent across multiple tests and/or users uploading results this is just how the writer works.

If you see upward spikes that are not consistent and do not match up with other results that have been uploaded to the InfinaDyne web site, you should check your configuration.  There may be settings on your system which are causing problems with TimeWrite and affecting your ability to effectively write CDs in general.

Q. What do downward spikes (slower) in the graph mean?

A. A downward spike indicates that the writer has delayed its response as being “ready” in comparison with other recent writes.  This is usually the result of flushing buffered data or having lost synchronization with the disc being written.

More information about this will probably become evident as we get more results from a broader span of writers.

Q. Why is the graph limited to 80 minutes?

A. Discs which meet the definition of valid CD-R and CD-RW media do not exceed 80 minutes in length.  Non-standard discs are available, but they can only be written by writers that ignore the standards.  We may support such discs in the future, but it is extremely unlikely they will offer any performance differences beyond 80 minute media.

Q. Why are there different speeds shown for a CD-RW disc than CD-R discs?

A. Writers support a subset of their CD-R writing speeds for CD-RW media and may further restrict this into different ranges depending on the type of CD-RW media inserted.  When a CD-RW disc is inserted, TimeWrite checks the drive to determine the speeds which are actually available from the writer.  TimeWrite does not make any assumptions about this but actually asks the writer.

When a CD-RW disc is inserted, an informational message is displayed showing the recommended range of writing speeds.  This does not restrict you to selecting a speed in that range, however.  If the writer is capable of writing at 8x on low-speed CD-RW media and the writer acknowledges this, TimeWrite will allow testing at that speed.

Q. How can manufacturers claim a fast writing speed when TimeWrite shows a slower speed?

A. We are not in a position to justify claims made by manufacturers.  Our testing is turning up surprising results with writers, some being faster than claimed and others being slower.  We believe that this testing is equivalent to how discs are actually written.  We are more than happy to work with manufacturers to resolve any issues that arise.

Q. What effect to different configurations have?

A. Differences in configuration (ATAPI vs. SCSI or USB, master/slave, etc.) are not expected to have significant effects.  There are a couple of reasons for this, but mostly TimeWrite is extremely focused on talking to a single device at the limit of the writer’s ability to communicate.  If the writer is limited because of a USB 1.1 bus, this will likely show up in other ways - such as write errors when a buffer underrun occurs.

Virtual memory settings are unlikely to have any effect on TimeWrite because it has a very small “working set” while it is testing the writer.  This means the amount of storage being referenced during the test is isolated to the program and a relatively small data buffer.  No other activity, such as reading from hard disk, is done during the test.

Other configuration choices, such as DMA usage, may or may not have an effect and this will be very interesting to observe as the number of uploaded results increases.  If we see significant differences between reports of a single writer we may request users with such devices to send us more information.  If you do not subscribe to the InfinaDyne mailing list, please do so as this is where such information will be given out.

Q. Why does TimeWrite not support DVD writing?

A. We are expecting a new release of TimeWrite sometime soon which will support DVDs.