ya mean inner edge? i.e. circumference is greater on outer edge as opposed
to inner edge when CD is spinning at same speed. so more data can be read at
Most/ALL CD-drives kinda use CAV (constant Angular Velocity) techniques to
improve CD read/writes. They used to also quote a 17x/52x or lets say a
12x/32x speed, 12x denoting inner edge read speed.
Seek time is indeed bad on CDs...probably around the 70ms mark at this stage
as opposed to 340ms on the old 2x Mitsumi Propriarity Drives(don't hide
it...I know ye all had them!). A big concern for me is CD and Motor
Balance...you could have all the speed in the world, but a poorly balanced
CD / Drive can slow things down dramatical with enforced read retires and
heat caused by friction by a wobbly Disc.
Most Mastered Software CD's (worth their salt) which are proggie-installs
are written (pre-empting read-optimisation) down sequentially at file level
, so when you install the proggie, hopefully 90% of the reads(depending on
install options selected) will be sequential (ie. fassst!)
From: Ronny B [mailto:nny at purehatred.org]
Sent: Monday, November 26, 2001 2:17 PM
To: ilug at linux.ie
Subject: Re: [ILUG] DVD install
On Mon, Nov 26, 2001 at 02:01:41PM -0000, Wynne, Conor wrote:
> Its all tantamount really. These drives, whether they state 12x, 32x,
> 64x etc etc, the trouble is, they take time to spin up to the max speed
> stated on the box. If you are talking about streaming large files off a
Not only that - a CD couldn't get more than 18x at the outer edge, either
(tests I read a lot about a while back stated so, anyway, and it seemed
logical back then ;).
Seek time is also pretty bad compared to harddrives, of course. This just
adds more waiting, anyway. CD speeds anobe 16x aren't really making much
difference, as CDs are mostly used for installation in the case of game-
junkies like me. Music CDs don't need more than 1x to play either ;)
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