The reader must be twice faster than the writer?

vbimport

#1

Today I ordered the 40x Plextor burner and while speaking with a friend he warned me that to write on-the-fly at a certain speed I'll need at least a 2x faster reader (eg. burner 8x, reader 16x). Is that really true??? :eek:


#2

Well, not exactly. Anyhow, I wouldn’t personally recommend copying ON-THE-FLY at all!

You see, when you have to duplicate a CD containing many small files, you’ll have to be aware of the seek-times. If you have, let’s say, 10,000 files of 50k each (that is ~500 MB), the seek time increases by each file… so at a writing speed of 16X (that is 2400 KB/s) you’ll have to read 48 files a second. An average seek-time is of about 100 ms so for 48 files it’s 4800 ms (5 times slower than necessary). So your on-the-fly copying will fail. There’s another problem as seen: if you expect the on-the-fly copying to go well without buffer underruns, you’ll have to do a simulation. Anyway, burning at 40x on-the-fly is impossible because of slow CD readings at the beginning of the CD. Not to mention that a single scratch on the source CD might make your copying process fail.


#3

OK, thank you. :slight_smile:
I will limit then my “on-the-fly” copies to Audio CDs only and at a low speed.


#4

i write about 75% of my cds on the fly using a 52 speed acer reader and a 24 speed liteon doing all kinds of cds music data games and the only problem you can have if the cd you are copying is scratched then i will make an image of the cd and copy it that way so writing on the fly is not that bad if you have got a good reader and writer both with dma enabled

  cheers   bighun

#5

Originally posted by bighun
[B]i write about 75% of my cds on the fly using a 52 speed acer reader and a 24 speed liteon doing all kinds of cds music data games and the only problem you can have if the cd you are copying is scratched then i will make an image of the cd and copy it that way so writing on the fly is not that bad if you have got a good reader and writer both with dma enabled

  cheers   bighun [/B]

I did over 3000 backups so far and I’ve encountered problems when reading large amounts of small data files. BIG problems. The CD-ROM slows ALOT.