Hot CD's and DVD's, is it okay?

[DataOrb]

Nothing really important, but after playing a DVD movie for about 20-30 minutes or using a cd rom for about 20-30 minutes, when I take it out of the drive, the disc is somewhat hot (I am not saying very hot, because it's not very hot, but it is somewhat hot, like touching the back of your monitor after it was on for 5 minutes...)...
my DVD Drive is the AOPEN 1040Pro which reads DVD's at X10 (13mb /sec) and CD roms at X40 (6mb sec), now using benchmarks, I got an X37 transfer rate from a CD ROM and an X8.9 Transfer from a DVD, so is the high spin speeds can affect the amount of heat on a disc? should I be worried?
thanks.


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[Maggi]

Ever thought about the technique that used for reading CD-ROMS & DVDs ?

What do you expect from those medias when a laser beam is pointed to them for 20 minutes ?



To make it short, don't worry, it's just normal ...

[Brian R.]

Why they get warm isn't important. Getting the media warm is normal.

[DentyCracker]

You should feel a CD just after you burn it. Now that's toasty!

[DataOrb]

but don't you think warm media can cause data errors? the heat can distrup the peaks and lows of the reflective peak...

------------------

"Excuse me for butting in, but I'm interrupt-driven..."
__________________________________________________ ____
Worstation Specs:
Asus P3B-F w/Celeron@680mhz
160mb PC100 7ns RAM.
Matrox G400 142/190Mhz.
IBM 75GXP 7200RPM 15Gb.
Seagate U8 4.1gb Hdd,
SBlaster Live! Digital.
17" Mag InnoVision 770Ti TrinitronFR Monitor @1152X864
Logitech MouseMan Wheel USB (on Everglide Giganta SE)
Focus 127keys MM Keyboard.
HP SCSI Cd-Rw 7200Si
AOpen X48 CD ROM.
AOpen 1040Pro Slot DVD
3Com NIc @ Tevel/3Com Cable Modem
Modded case, the "banshee". 6 fans.
3Com Palm IIIx + GoType + AxxPAC

[Brian R.]

Apparently not. I have made numerous disks without an error. Fill some disks with a file containing a checksum (e.g. zip) and keep them in your car or oven for a while and check them for errors if you're worried about heat. It takes alot of heat to bother the disks. You will notice a warping of the disk before you notice data loss.

[This message has been edited by Brian R. (edited 30 August 2000).]

[Fat Tone]

Hey Maggi
I never thought about it that way before. I just assumed that the heat was due to the motor speeds. Aren't the read beams just a few miliwatts?

Cheers, Tony.

[Chris B]

Don´t worry ´bout it!

When playing CD´s in my car-stereo they get hot, and I mean really hot, When I just burned a CD in my way old sony recorder it´s really hot, I leave cd´s lying in my car in scorching heat all day while at work, and never experienced a single problem with neither audio or data cd´s.

Try checking an unrecorded cd. The ones I have say on the cover/inlet how much heat they can take (offcourse I can´t remember the number)

[LAMFDTK]

Hot CD's + DVD's, is it OK?... Yea until your Wife or your Mom walks in....

[Pace]

Anyone know what speed (as in physical ) a CD/DVD disc spins at?

Ta, Paul.

[agallag]

A 1X CD-Rom spins from between 200-500 RPM (faster when reading the inside track, to achieve constant linear velocity). The fastest CD-Roms these days (about 50X) can spin as fast as 9000 RPM. DVDs don't have to spin as fast, because data on DVDs is much more dense, usually around 3000 RPM (they do spin fast when reading CDs though).

The kenwood multibeam drives also spin a lot slower, since they read seven tracks at once.

-=-=-
Andrew

[Pace]

Well by my calculations that makes a 50 speed drive spin those edges at over 100mph (~68kph)!

I knew hard drives hit these speeds and was curious how close CDs are - pretty close I think.

Ah, ok I'll work that out too!

5,400 hdd: 28kph/47mph
7,200 hdd: 38kph/62mph
10krpm hd: 53kph/86mph
15krpm hs: 80kph/129mph

Oh no - don't do it - ok - aaarrrghh - just thinking that travelling at 130mph must be a hard drive - groan...sorry

Paul.

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[agallag]

Pace, your math is a little screwy. Here's the actual numbers for the speed of the outside track of hard drives, assuming a 3.5 inch diameter:

5,400 RPM = 90.49 km/h or 56.23 mph
7,200 RPM = 120.6 km/h or 74.94 mph
10,000 RPM = 167.57 km/h or 104.12 mph
15,000 RPM = 251.36 km/h or 156.19 mph

and for a 9000 RPM 5.25 inch CD:

226.22 km/h or 140.57 mph

Notice how there's about 1.6 km/h in every mph. Your results are kind of backwards, and still weird...

-=-=-
Andrew

[Brian R.]

CDs have have a diameter of 11.84 cm or 4 21/32 inches.

for 5400 rpm, the outer data moves 120.5 km/hr (~72.3 mph). 9000 rpm gives 200.9 km/hr. The others are proportional.

[This message has been edited by Brian R. (edited 04 September 2000).]

[Rags]

Pretty close, Brian. This is how you figure it out: X=RPM. 5280 ft./ mile, 12 inches in a foot. This means 63,360 inches in a mile. Since rpm means rotations/minute, and we are going for miles/an hour we are interested in how many rotations in an hour. So, multiply RPM by 60. Here is the way I figured it:
EDIT:
This is for CAV CD's, by the way.
/EDIT:


60X(~3.14*4.65625)/63,360 This reduces to ~14.62X/1056.

This makes 5400RPM=~74.76 Mile/Hour

7200 RPM=~99.68 Mile/Hour
10000RPM=~138.45 Mile/Hour
15000RPM=~207.67 Mile/Hour




Rags



[This message has been edited by Rags (edited 04 September 2000).]