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Does putting a CD in the drive affect performance?

ADD Boy

Student
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Oct 31, 2003
Messages
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My parents and sister have been yelling at me for literally years , insisting that when I leave a CD in the drive, it makes the computer actually run slower.
Odd, you know, that I've never noticed this effect myself, even though I have about 10 times more computer knowledge/experience.
I 'd like to hear if any knowledgeable people know if putting a CD-ROM in the drive noticeably effects RAM, internet browsing, or any other capabilities of a computer, especially when the CD-ROM is not in use. I'm actually going to print out all the replies and show them to my family. I'm that desperate to prove them wrong :p
 
Any operation that does a "directory scan", eg. opening Windows Explorer, with a CD in the drive causes the CD to be spun up and read. This takes a number of seconds, and the app will wait until that completes before continuing.

So, depending on how your PC is set up, the answer is that a CD in the drive can possibly make the PC appear to run slower. In fact, it is simply waiting occasionally for the CD to come up to speed and come online each time it is accessed. A dumb Windows problem...

Best solution: Leave the CD out unless you need to use it.
 
Yea what Zep said, however, I feel I should emphasise the point that only when a program is actually trying to access the CD should a problem present itself, if you have a CD in the drive, and are surfing the net, there should be no problem, of course if you try to save something windows can try to access all drives at once for some reason and it will pause there.

But in most modern PC's if you try to save and only access, say the C drive, it won't spin up the CD ROM, only if you accidently click on it, like I have done, then you get annoyed waiting for it to spin up before you can do anything all the while cursing your own butterfingered ineptitude.

Where was I? Oh yes, it should not make any difference unless the CD ROM has spun down, and something tries to access it, causing a pause while it spins up.

I've only been working in IT, onsite hardware support and helpdesk, for about 5 years, so make of that what you will.

Also keep in mind, PC's can do strange things, I wouldn't be surprised if this could happen, but seeing as you don't notice it, I will happily fall back on the golden rule of IT, blame the user. ;) (feel free to delete that last comment before showing it to the users you mentioned.....your family..... that's what you called them.)
 
I get the impression that sometimes IE cannot distinguish between "local" and "Internet" file systems, so some sort of "directory scan" that is intended only for file systems on the Internet will result in a local file scan as well, hence the spin-the-CD delay occuring.

Would this be related to the enabling of Microsoft workgroups on the PC? Someone knowledgeable???
 
To be honest I have no idea whether this is true Zep, mainly because I un-install IE the first chance I get.

However, I have never heard of this happening. Keep in mind that windows XP has a plethora of complete bollocksy crap that runs in the background monitoring what programs you use, how often you use them, and a bunch of other stuff. Also, MSN messenger can do wonderfully slow things to your PC.

Perhaps we should find out what OS ADD boy has?
 
Hmmmm.

I've had a bit of a twiddle with the PC at work (W2K), and it appears that the CD will spin up if the "browse for directory/file" widget is invoked, eg. from the Run command, or File Save As option in apps. This seems to be the result of an implicit directory scan...

Oh what joy it is playing with Windows internals...
 
To quote the Reverend Lovejoy,

"...ooooh short answer yes with an if, long answer no with a but..."

Under ideal conditions having a cd in the drive shouldn't impact system performance at all unless something is accessing it. But that "something" could be opening "My Computer", a shortcut to the cd drive on the desktop, a shortcut to a file on a cd in the programs directory (some kids games do this). Generally when windows does it's "read ahead" those shortcuts will be included.

Additionally, if the system is having trouble reading a cd explorer will hang until it can read the volume label of the cd. Even though this should timeout eventually, sometimes it doesn't. A reboot is sometimes required.

Zep,
This also applies to shortcuts to network resources.
 
Yes, the "directory scan" applies to all file-system(s) "visible" to the machine you are working on, including network file shares. If you invoke a process that requires to look at these "visible directories", a scan initiates. You can get the same effect with a floppy in a drive as with a CD, btw.

There are some smarts involved too - network services that do not respond will time-out quickly, giving you the "offline" indicators (eg. a network file share symbol in Windows Explorer with a red cross on it).

On NT-based systems, failure to read CD labels will timeout eventually - about 60 seconds from my own experience. Or just eject the CD manually - all will quickly right itself. Mind you, that's not great anyway.
 
I don't think any of this is helping ADD Boy, I think what he will have to do is test to see if this is the case, then if it is we can get a more detailed list of the symptoms and worry about what's causing it then.

As I said, it's probably the users fault anyway. :D
 
IME nothing is more likely to slow down or crash a Windows system than a CD with a child's sticky fingerprint on it.
 
SquishyDave said:
I don't think any of this is helping ADD Boy, I think what he will have to do is test to see if this is the case, then if it is we can get a more detailed list of the symptoms and worry about what's causing it then.

As I said, it's probably the users fault anyway. :D
Click to expand...
PIBKAC
 
I work for one of the top 3 Hard Drive companies. Besides what is listed above, a spinning CD *COULD* cause vibrations that would effect the Hard Drive Reading and Writing. Since much of the memory that the OS uses gets cached to virtual memory on the hard drive, any thing that slows that process down will slow down the whole system.

To write to the disk, the drive must hold the write head still with an accuracy of about 1 - one millionth of an inch (rough number biased on 100K tracks per inch and 10% on track error limit). Now add in a vibration and the drive will blow a rev waiting to the head to steady up on the track. Reading is much easier since you can read farther off track than you are allowed to write.

I leave CDs in all the time since they spin down when they are not being used. If the CD ain't spinning it should not effect the system much at all.
 
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