BR/HD-DVD Thread
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Unless both HD-DVD and Blu-Ray will be incapable of dual-side/dual-layering during their lifespans, you seem to be not supplying that critical final step in your comparison. That would get HD-DVD over 60 and Blu-Ray over 100 which in your own words gets us "talking."jvd said:
Meanwhile it's not like DVD-9 has been exploding in popularity nor been a quick technical advancement for the format... (And is starting out pretty damn expensive in its own right. -_- )The Ritek-acquired NFR technology, at least, does what the blue lasers were adopted to do--shrink recording marks to fit more on a disk. (I don't know enough about it to know if the "as much as 100GB" means dual-side/dual-layer in the same way as DVD-18, though. Which may mean it emulates Blu-Ray storage-wise in pretty much the same manner.) I don't think it can yet be told how laser costs would relate either without knowing how near-field recording is achieved technologically. Meanwhile it's aimed further down the road, doesn't have the support structure HD-DVD nor Blu-Ray have in place currently, AND may represent technology that could be worked into blue-laser tech for much larger effect. (Though Hitek owns the patent for 5 years, it could be acquired by another player later--especially if they'll only own it for two more years before actually starting mass production. And it doesn't prevent similar concepts from coming into by that time either.) Not to mention we also don't know yet whether its transfer rates to know if it would be viable for HDTV recording, or if it would mainly be be used as a mass storage device.
Jury's still out. But in the meanwhile, HDTV is trying to push forward full steam, so they're not going to wait that long to have something with which to show off. And for now, there are only two players for them to latch onto that can make their presence felt and have forseen growth for a good number of years following. We can always wait for more tech--but the market wants to sell us more things we obviously need so I don't expect them to sit around.
And invariably, when the priced drop enough, we'll still pick 'em up.
nondescript
Regular
I was bored, so I wrote this long post comparing BD and HD-DVD. Hopefully it will help to dispell some myths and save us all a little time. I admit this is OT, but hey, this whole thread is OT.
Technical Specifications:
DVD:
Capacity: 4.7GB(single layer) 9.4GB (dual layer)
Laser wavelength: 650 nm
Numerical Aperture: 0.60
Protection Layer: 0.6 mm
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2
Blu-Ray(BD):
Capacity: 27GB(single layer) 54GB (dual layer)
Laser wavelength: 405 nm
Numerical Aperture: 0.85
Protection Layer: 0.1 mm (and 0.6 mm ??)
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2
HD-DVD:
Capacity: 20GB(single layer) 32GB (dual layer)
Laser wavelength: 405 nm
Numerical Aperture: 0.65
Protection Layer: 0.6 mm
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2, H.264
Comments:
Laser Wavelength - BD and HD-DVD use the same wavelength, 405 nm. I know in my previous post I said that Sony was developing a 408 nm wavelength laser. Well, I checked the pamphlet again, and it says 408nm, and it says Blu-Ray. (I guess 405 nm and 408 nm aren`t very different. Most materials do not have wildly different refraction indices for slightly different wavelengths. Also, since BD has a protection layer that is 6 times thinner than HD-DVD, it is roughly 6 times less sensitive to the refraction of the protection layer.)
Protection Layer - This simply means the amount of material the laser beam has to pass through to reach the reflective layer (where the data is). I guess you could call it the cover layer instead, but it`s not my choice of terminology. This is not to be confused with the protection coating, which has to do with preventing scratches and the like.
A Little Physics
Quick and painless, I promise.
The three main characteristics of optical media are: wavelength, numerical aperture, and protection layer thickness. BD and HD-DVD have the same wavelength, so we can ignore that.
Disk Capacity is proportional to: (Numerical Aperture)^2/(Wavelength)^2
This is the physical limit - obviously, we need to consider ECC, file system overhead, etc... BD should theoretically allow 71% more data than HD-DVD, but that is clearly not the case. This may reflect a more conservative design.
Disk Flatness Tolerance is proportional to: (Wavelength)/(Protection Layer Thickness*(Numerical Aperture)^3)
A quick calculation shows that BD is about 160% more tolerant to disk flatness imperfections than HD-DVD.
Protection Layer Thickness Tolerance is proportional to: (Wavelength)/(Protection Layer Thickness*(Numerical Aperture)^4)
A quick calculation shows that BD is about 80% more tolerant to protection layer thickness imperfections
Similarities between HD-DVD and DVD
The most obvious and important similarity is the protection layer thickness. Both DVD and HD-DVD have protection layers of 0.6 mm, placing the data layer at approximately the center of the disk - CD/DVD/BR/HD-DVD all have a disk thickness of about 1.2 mm.
This similarity is the basis of the claim that HD-DVD and DVD have similar manufacturing processes. After the masters are created, single-layer DVDs are made by making two substrates (each 0.6 mm), coating a reflective layer on one of the substrates, and gluing them together, with the reflective layer sandwiched in between. HD-DVD can use almost the same process - but everything will be harder, due to the smaller pits and lower tolerances. (Creating the masters is quite different, of course)
BD Manufacturing
BD has a 0.1 mm protection layer. Thus it has a 1.1 mm substrate, and requires only one substrate per disk. The reflective layer and the 0.1 mm protection layer are then added to the substrate. This makes fabricating BD actually easier than HD-DVD - since only one substrate is needed, they don`t need to worry about birefringence. Not to mention they only need half the injection molding capacity.
Because the laser does not pass through the 1.1 mm substrate layer, it can be made of virtually any material that can provide rigid mechanical support for the reflective layer. Hence, it is entirely possible to make BR disks from mostly paper. Thus, the BR substrate layer can be cheaper than HD-DVD or DVD. As for right now, they just use a cheaper plastic. However, these savings amount to at most a few cents, since plastic very, very cheap.
Making BD disks from paper:
http://www.extremetech.com/article2/0,1558,1573314,00.asp
The thin protective layer and the high density make the BR more vulnerable to scratches and other surface damage. Thus, a hard protective coating is necessary, or a caddy. There are BR formats for both caddy and bare-disks. The bare disks will almost certainly have protective coatings. The protective coatings are spin-coated, and amount to, at most, a few cents. Coatings currently used can prevent scratchs from test needles with 200 mN force.
As mentioned before, BR disks have higher tolerance margins than HD-DVD disks, which should also make manufacturing the disks easier.
(There has been some talk of a 0.6 mm protection layer format, which would share the same production methods described for HD-DVD and DVD. However, this thicker protection layer would largely negate all the advantages of BD, so I find this confusing. If someone knows more about this, please enlighten me.)
HD-DVD and BR mastering
Because both have data densities much higher than DVD, they cannot use current DVD mastering techniques. The most straightforward method is e-beam lithography, but more ambitious (cheaper?) methods are deep-UV with liquid immersion (being developed for the semiconductor industry), and blue laser with inorganic resist (haven`t read up on this, my guess is the inorganic photoresist creates sharper masks). The latter method, also called phase transisiton mastering (PTM), was developed in house by Sony specifically for BR and is cheaper than DVD mastering.
However, I don`t see any good reason why PTM can`t also be used by HD-DVD, so I think the mastering costs should be roughly equal. (Unless licensing the IP from Sony adds a noticeable cost)
HD-DVD and BR players
HD-DVD and BR both use 405 nm, and DVD is 650 nm. Thus, they are both not compatable with DVD - both must have seperate lasers for DVD playback. BR has a numerical aperture of 0.85, HD-DVD is 0.65, and DVD is 0.60. Thus, they cannot have the same optical system. Maybe clever engineering can allow most elements of the optical system to be reused, but the fundamental fact remains that they have different optical specifications, and require different optical systems.
BD, because of the much thinner protective layer, does not need to worry as much about beam-splitting or disk tilt, simplifying player design.
As mentioned before, BR disks have higher tolerance margins than HD-DVD disks, which should make player design easier. (Now obviously, you can`t have it both ways - but I`m sure the BD consortum will distribute the higher tolerance between disk and player manufacturing specs in a way that minimizes total cost - they would have to be stupid not to)
Summary
HD-DVD is primary technical merit is some compatiability with DVD disk manufacturing. This should allow HD-DVD disks to be produced at prices similar to DVD disks relatively quickly, since many economies of scale have already been acheived by the DVD market.
BR is more technically ambitious, using a higher numerical aperture and thinner protective layer. This provides several advantages in both player design and disk manufacturing. The downside is that BR shares less in common with DVD manufacturing, although many of the same techniques, machines and materials can be reused. BD disk mass production has the potential to be cheaper than DVD disk production.
Second Opinion:
http://www.technologyreview.com/articles/04/07/wo_brown072204.asp
Technical Specifications:
DVD:
Capacity: 4.7GB(single layer) 9.4GB (dual layer)
Laser wavelength: 650 nm
Numerical Aperture: 0.60
Protection Layer: 0.6 mm
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2
Blu-Ray(BD):
Capacity: 27GB(single layer) 54GB (dual layer)
Laser wavelength: 405 nm
Numerical Aperture: 0.85
Protection Layer: 0.1 mm (and 0.6 mm ??)
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2
HD-DVD:
Capacity: 20GB(single layer) 32GB (dual layer)
Laser wavelength: 405 nm
Numerical Aperture: 0.65
Protection Layer: 0.6 mm
Data Transfer Rate: 36 Mbps (1x)
Video Compression: MPEG2, H.264
Comments:
Laser Wavelength - BD and HD-DVD use the same wavelength, 405 nm. I know in my previous post I said that Sony was developing a 408 nm wavelength laser. Well, I checked the pamphlet again, and it says 408nm, and it says Blu-Ray. (I guess 405 nm and 408 nm aren`t very different. Most materials do not have wildly different refraction indices for slightly different wavelengths. Also, since BD has a protection layer that is 6 times thinner than HD-DVD, it is roughly 6 times less sensitive to the refraction of the protection layer.)
Protection Layer - This simply means the amount of material the laser beam has to pass through to reach the reflective layer (where the data is). I guess you could call it the cover layer instead, but it`s not my choice of terminology. This is not to be confused with the protection coating, which has to do with preventing scratches and the like.
A Little Physics
Quick and painless, I promise.
The three main characteristics of optical media are: wavelength, numerical aperture, and protection layer thickness. BD and HD-DVD have the same wavelength, so we can ignore that.
Disk Capacity is proportional to: (Numerical Aperture)^2/(Wavelength)^2
This is the physical limit - obviously, we need to consider ECC, file system overhead, etc... BD should theoretically allow 71% more data than HD-DVD, but that is clearly not the case. This may reflect a more conservative design.
Disk Flatness Tolerance is proportional to: (Wavelength)/(Protection Layer Thickness*(Numerical Aperture)^3)
A quick calculation shows that BD is about 160% more tolerant to disk flatness imperfections than HD-DVD.
Protection Layer Thickness Tolerance is proportional to: (Wavelength)/(Protection Layer Thickness*(Numerical Aperture)^4)
A quick calculation shows that BD is about 80% more tolerant to protection layer thickness imperfections
Similarities between HD-DVD and DVD
The most obvious and important similarity is the protection layer thickness. Both DVD and HD-DVD have protection layers of 0.6 mm, placing the data layer at approximately the center of the disk - CD/DVD/BR/HD-DVD all have a disk thickness of about 1.2 mm.
This similarity is the basis of the claim that HD-DVD and DVD have similar manufacturing processes. After the masters are created, single-layer DVDs are made by making two substrates (each 0.6 mm), coating a reflective layer on one of the substrates, and gluing them together, with the reflective layer sandwiched in between. HD-DVD can use almost the same process - but everything will be harder, due to the smaller pits and lower tolerances. (Creating the masters is quite different, of course)
BD Manufacturing
BD has a 0.1 mm protection layer. Thus it has a 1.1 mm substrate, and requires only one substrate per disk. The reflective layer and the 0.1 mm protection layer are then added to the substrate. This makes fabricating BD actually easier than HD-DVD - since only one substrate is needed, they don`t need to worry about birefringence. Not to mention they only need half the injection molding capacity.
Because the laser does not pass through the 1.1 mm substrate layer, it can be made of virtually any material that can provide rigid mechanical support for the reflective layer. Hence, it is entirely possible to make BR disks from mostly paper. Thus, the BR substrate layer can be cheaper than HD-DVD or DVD. As for right now, they just use a cheaper plastic. However, these savings amount to at most a few cents, since plastic very, very cheap.
Making BD disks from paper:
http://www.extremetech.com/article2/0,1558,1573314,00.asp
The thin protective layer and the high density make the BR more vulnerable to scratches and other surface damage. Thus, a hard protective coating is necessary, or a caddy. There are BR formats for both caddy and bare-disks. The bare disks will almost certainly have protective coatings. The protective coatings are spin-coated, and amount to, at most, a few cents. Coatings currently used can prevent scratchs from test needles with 200 mN force.
As mentioned before, BR disks have higher tolerance margins than HD-DVD disks, which should also make manufacturing the disks easier.
(There has been some talk of a 0.6 mm protection layer format, which would share the same production methods described for HD-DVD and DVD. However, this thicker protection layer would largely negate all the advantages of BD, so I find this confusing. If someone knows more about this, please enlighten me.)
HD-DVD and BR mastering
Because both have data densities much higher than DVD, they cannot use current DVD mastering techniques. The most straightforward method is e-beam lithography, but more ambitious (cheaper?) methods are deep-UV with liquid immersion (being developed for the semiconductor industry), and blue laser with inorganic resist (haven`t read up on this, my guess is the inorganic photoresist creates sharper masks). The latter method, also called phase transisiton mastering (PTM), was developed in house by Sony specifically for BR and is cheaper than DVD mastering.
However, I don`t see any good reason why PTM can`t also be used by HD-DVD, so I think the mastering costs should be roughly equal. (Unless licensing the IP from Sony adds a noticeable cost)
HD-DVD and BR players
HD-DVD and BR both use 405 nm, and DVD is 650 nm. Thus, they are both not compatable with DVD - both must have seperate lasers for DVD playback. BR has a numerical aperture of 0.85, HD-DVD is 0.65, and DVD is 0.60. Thus, they cannot have the same optical system. Maybe clever engineering can allow most elements of the optical system to be reused, but the fundamental fact remains that they have different optical specifications, and require different optical systems.
BD, because of the much thinner protective layer, does not need to worry as much about beam-splitting or disk tilt, simplifying player design.
As mentioned before, BR disks have higher tolerance margins than HD-DVD disks, which should make player design easier. (Now obviously, you can`t have it both ways - but I`m sure the BD consortum will distribute the higher tolerance between disk and player manufacturing specs in a way that minimizes total cost - they would have to be stupid not to)
Summary
HD-DVD is primary technical merit is some compatiability with DVD disk manufacturing. This should allow HD-DVD disks to be produced at prices similar to DVD disks relatively quickly, since many economies of scale have already been acheived by the DVD market.
BR is more technically ambitious, using a higher numerical aperture and thinner protective layer. This provides several advantages in both player design and disk manufacturing. The downside is that BR shares less in common with DVD manufacturing, although many of the same techniques, machines and materials can be reused. BD disk mass production has the potential to be cheaper than DVD disk production.
Second Opinion:
http://www.technologyreview.com/articles/04/07/wo_brown072204.asp
Excellent post nondescript! Not only did you beat me, you totally outclassed me
Allways understimating their work
jvd said:
Allways understimating their work
Code:
What's the difference between Blu-ray and DVD?
Parameters
BD BD DVD DVD
Recording capacity 27GB 54GB 4.7GB 9.4GB
Number of layers single-layer dual-layer single-layer dual-layer
Laser wavelength 405nm 405nm 650nm 650nm
Data transfer rate 36Mbps 36Mbps 11.08Mbps 11.08MbpsA single-layer disk is ~25GB for Blu-Ray and a dual-layer disk is ~50GB. (Hyar.) (And the easy numbers for HD-DVD single- and dual-layer are ~15/30--but there's always room for adjustment in both.)
I'm actually not quite sure as to the "side-ous-ness" as it were, but I assume it's operating similarly to DVD's progression. Not to mention the current recorders are, to my knowledge, all single-sided. I assume DSDL is coming down the pipe for both at some point.
I'm actually not quite sure as to the "side-ous-ness" as it were, but I assume it's operating similarly to DVD's progression. Not to mention the current recorders are, to my knowledge, all single-sided. I assume DSDL is coming down the pipe for both at some point.
The figures at the end of the Blu-Ray FAQ for HD-DVD capacity has always made me boggle a bit. 20GB for single-layer and 32GB for dual? Is that how the recordable disks vary from the read-only ones? And... er... why? (And how does it lose 8GB in the transit to dual-layer? DVD doesn't fully double capacity either, but HD-DVD loses more (80% versus 90%). And what doesn't Blu-Ray seem to lose ANY?)
nondescript
Regular
Vince said:Excellent post nondescript! Not only did you beat me, you totally outclassed me
Haha ... the key word is "bored" - until universities here let out for summer vacation (this week) - I have few friends to bum with.
With regards to "layered-ness" and "sided-ness" (or as cthellis42 says, "side-ous-ness"
), I don`t see any problems for either HD-DVD or BR. BR will probably need two 0.5 mm substrates glued back to back to provide sided-ness, which will raise costs, but, HD-DVD needs two substrates too, so I don`t see an advantage either way.Layers - well, to be honest, I don`t really understand how layers are built, so can`t comment on that. But since they have published specs on layers, there`s not much point arguing about that.
nondescript
Regular
cthellis42 said:
Hmm, didn`t notice when I was reading it...why is it that I never notice these kinds of things...
I think I can answer this. The way layers are read is the laser focus is changed to to slightly different depth. To read the deeper layer, light has to pass through the other layer, bounce off the deep layer, and reflect back. This means that the shallower layer must not be made perfectly reflective, or no light can pass through. Reading the deeper layer is affected by the shallower layer. This degrades signal quality, so they need to decrease density to compensate.
BR has solved this dilemma somehow. My guess is this. Go google up some schematics on BR media, and you`ll see that the data is recorded in "grooves". The spacing between bits radially on the disk is about twice as large as the spacing circularly. This is probably why the disk density for BR is lower than the theoretical limit, to provide this grooving.
The lower layer is probably written in between the grooves. It`s like a movie theater - the seating is such that your head is in between the heads of the people in the row in front of you, so everyone can see. In this case, the laser can "see" both layers, because they are interlaced.
This is probably why BR media is written as one continuous spiral - because then the two layers could be read in EXACTLY the same way - requiring no additional control logic (other than changing the laser focus).
(EDIT: It`s probably not as clean as that, since nothing can be that easy. When reading the lower track, the laser probably still gets "clipped" by the upper layer - but anyways, the benefits are obvious, and clearly, BR engineers have managed to create dual-layer disks with no loss in data density)
That`s my speculation.
As for ROM vs recordable, that`s pretty easy - ROM disks can use physical pits, because they are stamped out in factories. Recordable disks must use some other means, usually a dye of some sort. The contrast is not as sharp, resulting in reduced signal, so they need to reduce data density.
Actually quad-layer discs have already been talked about for BD as well(it was at a recent show where future HD media was presented) - by the time 100GB DVD rolls around in 2007 they may already be available, who knows.
Anyway, slightly to another topic - for people that see these formats as viable in upcoming consoles, even if you believe that basic drive price will go down enough to be reasonable - a console would need at least 4xspeed BD/HD-DVD drive... arguably more given the increase in capacity (Xenon's DVD is currently specced at 16x).
Coupled with rise in media cost, I would really like to hear some arguments that justify the economics of stuffing this in a nexgen console, because right now I can see mostly negatives (ignoring my personal greed for more space and latest and greatest shiny gadgets of course).
No, but... see... that's what I would expect. Except other sources also mention that the ROM is 15GB while the recordable media is 20GB, which is what makes it a bit confusing.nondescript said:
Fafalada said:
Pardon me while I vomit blood...(This is at least along the lines of why the benefits of new tech are always non-obvious.
)Question, though. Do you know if that's on top of dual-sided disks, or the method they're planning on getting to 100GB itself? (Which may mean dual-sided disks themselves get pushed further down, or are not quite feasable combined with quad-layer?) Or is this a matter of semantics? It seems DVD-18 is referred to as "quad-layer" a bit as well.
I don't really have one for Xbox 2 (especially since it's supposed to be the first out the door) nor Nintendo wanting to pursue those options just yet. Sony is the only one I can see wanting to front it, because the tech is in-house advantageous, and it just behooves them to get a giant leg up on the competition by putting it in a device that will undoubtedly sell boatloads for entirely its own reason. Lost initial revenue can be made up over time as they and their partners will be eternally looking to reduce the cost of the drive components, and they can roll those savings in quickly. (They'll probably be doing a lot less process-shrinking and other engineering on the other chipware than they've done for the PS2, so I imagine they'll be looking elsewhere in the machine that can most use cost re-engineering and translate elsewhere as well.) Meanwhile, even just KNOWLEDGE of Blu-Ray being in the PS3 would hold many consumers off other options (both in the console and HD-player arena).
The first problem is in "how MUCH would they be losing?" as the hardware costs of CELL and other parts of the system will be at a premium, and shelling out way too much for initial units would be burdensome. I don't have any idea of the relative costs (since invariably even if they didn't put in Blu-Ray they'd have to put in a higher-end DVD player to support higher storage and perhaps better access speeds) at those volumes in more than a year's time, so... no way to tell on that front.
Much more of a problem, I figure, would be disenfranchising their fellow hardware producers, as I can't imagine them wanting to see Blu-Ray players drop to top-end DVD player prices THAT quickly. (Which they'd have to if the PS3 remains reasonably priced for a console and they don't want to lose the bulk of their sales to it.) Even the BR recorders would have to drop to a much more reasonable premium because of it, even if they didn't conflict directly. Unless there's a distinct agreement between them all to push BR out the door as no other piece of tech has before it, I could see a number of them sour and disenfranchised. (Since not all of them make the media, which I think would be the biggest ultimate beneficiaries of a fast Blu-Ray adoption and becoming the de-facto standard.)
If there IS confirmation of BR appearing in PS3, though, I could possibly see Microsoft willing to toss their own cash at getting HD-DVD in simply to counteract all those influences, as it behooves them to weaken Sony's position. Of course if Sony's smart they wouldn't announce it until after it's too late to change Xbox 2's spec...
The easiest adoption for all corporate hands, though, would be a multi-model PS3 available at launch or soon after. This wouldn't force Sony to subsidize the cost, nor would it force their partners down to a price level that would be unreasonable to them on their own hardware. It would, however, confuse the consumer, complicate the game distribution model, and put Blu-Ray's adoption by developers at "tepid" as the cheaper system will invariably sell a lot more, and games would primarily be aimed at DVD capacities and speeds, neutralizing Blu-Ray's benefits in that arena. I'm sure we'd see some "special edition" BR games from the top-end developers, but it would take a while, filter in slowly, and ultimately be a giant shrug from the gaming standpoint. (Unless a few years later the PS3 were to move to all-BR models for the same cheaper price.)
...
All in all, it's just a bit confusing and complicated.
Most of the hardware vendors of Blue Ray and HD DVD are not making as much money on DVD as they would have liked. DVD players became commoditized a lot faster than they expected and there are suggestions that Japanese companies got their pockets picked by the cheap Chinese manufacturers, which have driven prices way down.
So I think they would like to see a transition to new hardware where they would see higher profits. Of course, they have to get the content owners to cooperate and right now, the movie studios are in no hurry to get off the DVD gravy train.
Sure Blue Ray on the PS3 may force BR hardware prices to drop. But it would also accelerate the installed base of BR players/recorders, making it more likely to get software support.
So it's hard to imagine BR hardware vendors being opposed to BR drive on the PS3 (assuming that costs are low enough that they could price their players and recorders competitively and still turn a good profit).
So I think they would like to see a transition to new hardware where they would see higher profits. Of course, they have to get the content owners to cooperate and right now, the movie studios are in no hurry to get off the DVD gravy train.
Sure Blue Ray on the PS3 may force BR hardware prices to drop. But it would also accelerate the installed base of BR players/recorders, making it more likely to get software support.
So it's hard to imagine BR hardware vendors being opposed to BR drive on the PS3 (assuming that costs are low enough that they could price their players and recorders competitively and still turn a good profit).
Ah, but so much rides between those last parentheses, wco...
V3 said:
DVD 4X = 4 * 11.08Mbps = 44.32Mbps
BD 4X = 4 * 36Mbps = 144Mbps
But... For instance the PS2 has 32Mo of ram to fill (In a "perfect world") the ram will be filled in less than a 6 sec, if the PS3 have 256Mo or worse 512Mo (worse in this case, of course), it will take 14 sec to fill 256Mo and 28 sec for 512Mo (Always in a perfect world , without seek times etc...).
So more than anything, the loading times next gen might go up and not down... :?
Except if the developers are smart enough, and uses trick such as start a level before having totally filled up the ram with datas, etc...
nondescript
Regular
aaaaa00 said:
These are (apparently) pretty standard "rule-of-thumb" metrics - so I suggest you head to your local university`s EE/Applied Physics/Materials Science/Physics library, look up Optical Storage Media, and find a book with a more theoretical approach.
I got these equations in the proceedings of a optical storage symposium (forgot the year and title), and the paper was by Phillips. I can`t say I understand it fully (for example, I don`t see why disk flatness tolerance is inversely proportional to the cube of numerical aperture, I think it should only be inversely proportional to the square of numerical aperture), but I understand enough to know what`s going on.
As for the actual calculation, just plug in the numbers.
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