CD's vs. DVD's

[Bruce]

I must be way behind on the latest technology. I learned yesterday that they make games in DVD version. I thought DVD's were only for movies. A co-worker told me today that he got a dual CD and DVD burner for his computer last weekend. He said that DVD's hold more memory.

Three questions for the techno-geeks:

1. What are the differences between CD's and DVD's?

2. Will DVD's replace CD's in the near future?

3. Should I buy a DVD burner for my computer, or is the next wave in technology right around the corner?

[HarryKeogh]

1. the lasers read pits and spaces on the discs. the pits and spaces are smaller on dvds. it also used a different type of laser to read the info (watch for new generation HighDef dvds and players which will use a blue laser to read the info...also be prepared for a format war like the old VHS/Beta war of the early 80's)also dvds can be dual-layer (once the laser gets to the end of a disk it reads another set of information going the opposite direction (I think). this accounts for the occassional slight pause when you watch a DVD) and dual sided.

2. no. CDs are here to stay until the next format comes and does away with both DVDs and CDs

3. buy a DVD burner. they're soooo cheap. this is a matter of opinion for you though I think but I say go for it.

[RussDill]

There are two different issues here, format and media. Two basic different types of media, CD and DVD, only important different? DVD media holds a lot more.

As far as format, you got your data, your audio, and your DVD (which is really a bunch of big files in a data format). You can burn a DVD format disk onto CD media, it'll just be a short DVD. Use wikipedia if you want some more info.

[Rolfe]

Originally posted by Bruce
A co-worker told me today that he got a dual CD and DVD burner for his computer last weekend.I opted for one of these over a year ago. So far I've only used the burner in CD mode, and the DVD part for viewing DVDs (see the computer forum area for my current grief in that department). However, I was interested in future-proofing my purchase. My track record is get a new PC, then use it the way it came till something in it falls to bits. Takes about six years usually. Hoping that the DVD facility will keep the capability reasonably up to speed for that length of time.

And provide capacity for backups if I ever get that organised.

Rolfe (lucky not to have lost every bit of data last time actually....)

[Matabiri]

Originally posted by Bruce
1. What are the differences between CD's and DVD's?

2. Will DVD's replace CD's in the near future?

3. Should I buy a DVD burner for my computer, or is the next wave in technology right around the corner?

In user-friendly terms... a CD will hold about 700 Mb, a DVD will hold about 6 Gig.

If you need that kind of archival capacity, buy one. Otherwise, you'll never use it.

[Ove]

And ... a good advice, WAIT.... Prices on DVD's are dropping and their performance is skyrocketing (well allmost). Wait a year of so then they'll be very affordable and in a decent quality. The present is around 8 x speed and if you remember your old 8 x CD burner and then imagine burning a disk that holds 8-10 times the information...... Get the picture??:D

[Skeptical Greg]

Originally posted by Ove
And ... a good advice, WAIT.... Prices on DVD's are dropping and their performance is skyrocketing (well allmost). Wait a year of so then they'll be very affordable and in a decent quality. The present is around 8 x speed and if you remember your old 8 x CD burner and then imagine burning a disk that holds 8-10 times the information...... Get the picture??:D

Something to keep in mind..

1x CD is about 150 Kbs ( kilo bytes per second )

1x DVD is 1.1 Mbs ( mega bytes second )

There are currently 16x DVD writers on the market, but reliable ( cheap ) media is about 8x ..

[malbui]

Originally posted by Ove
And ... a good advice, WAIT.... Prices on DVD's are dropping and their performance is skyrocketing (well allmost). Wait a year of so then they'll be very affordable and in a decent quality. The present is around 8 x speed and if you remember your old 8 x CD burner and then imagine burning a disk that holds 8-10 times the information...... Get the picture??:D

But it doesn't matter how long you wait... there's an immutable law that says that the simple act of buying a piece of hardware will provoke either an industry price-war or a major technological advance leading to plummeting prices. Me, I refuse to look at adverts or catalogues for three months after splashing out because I know it'll make me depressed.

[Matabiri]

Originally posted by malbui
But it doesn't matter how long you wait... there's an immutable law that says that the simple act of buying a piece of hardware will provoke either an industry price-war or a major technological advance leading to plummeting prices. Me, I refuse to look at adverts or catalogues for three months after splashing out because I know it'll make me depressed.

Even that doesn't necessarily help. A week after I bought my laptop Apple actually e-mailed me to tell me they were releasing a new range of Powerbooks, which were faster, cheaper, and came with DVD burners, and perhaps as someone who'd bought one in the past I'd be interested?

[Dragon]

Originally posted by Matabiri
In user-friendly terms... a CD will hold about 700 Mb, a DVD will hold about 6 Gig.

If you need that kind of archival capacity, buy one. Otherwise, you'll never use it. Agreed. Our computer is about 2 years old and came with a DVD player and a separate CD burner. I'm thinkng this will do us until those blue laser things are affordable.

[HarryKeogh]

http://www.cnn.com/2004/TECH/biztech/12/09/tech.disney.dvd.reut/index.html

an article on the next format of DVD. whichever company can woo the biggest studio to their side wins. I'll sit by the sideline until a winner is announced. (I don't want to get stuck with an RCA Videodisk player again)

[roger]

There's a better Slate (http://www.slate.com/id/2110495/) article on the same topic that goes into the technical details of each product, and why the movie industry is pushing for the inferior technology (cheaper to produce). They also make the probably sound point that sense this technology will be used for computers, video games, etc., that it is unlikely that movie studios will be able to drive the format selection.

[RussDill]

Originally posted by malbui
But it doesn't matter how long you wait... there's an immutable law that says that the simple act of buying a piece of hardware will provoke either an industry price-war or a major technological advance leading to plummeting prices. Me, I refuse to look at adverts or catalogues for three months after splashing out because I know it'll make me depressed.

Remember that cd readers toped out years ago, and cd burner speeds toped out shortly there after.

[rppa]

My $.02

Originally posted by Bruce
I must be way behind on the latest technology. I learned yesterday that they make games in DVD version. I thought DVD's were only for movies.

A DVD is just a high-density digital storage medium. In fact I think the standards for computer use were nailed down before they were for use in movie distribution. The first DVD movies I saw were played through a computer at a PC trade show, ca. 1998.

Ever buy a product that required multiple CDs, like those phonebooks on disk, or the game "Riven"? Pain in the neck. Games with lots of media have already outgrown the CD and need DVDs.

A co-worker told me today that he got a dual CD and DVD burner for his computer last weekend. He said that DVD's hold more memory.

Pet peeve: the use of "memory" for permanent storage. "Memory" goes away when the power is off. (No wiseasses start talking about non-volatile memory, please).

Yes. A DVD is essentially a high-capacity CD. A *very* high-capacity CD. That's why DVD drives are also usually CD-compatible.

What are the differences between CD's and DVD's?

DVDs hold more. Music, movies, phone numbers, whatever.

Will DVD's replace CD's in the near future?

As the default drive on new computers, haven't they already? As a storage medium, no. If you aren't storing moving pictures, CDs have plenty of capacity and they're cheap. There are lots of occasions when you want to store a lot more data than will fit on a floppy, less than a DVD.

Should I buy a DVD burner for my computer, or is the next wave in technology right around the corner?

My hard drives are now in the 10s of GB. Backing them up to CD is a really excruciating process that takes a stack of CDs and a lot of babysitting. The medium is expensive. Last time I looked, one recordable DVD was around $30-40 as I recall.

If you are in the market for a CD burner, you probably want to at least price the DVD burners that also do CD-R. I regret not getting a CD-RW (that's the reusable CD). I do a lot of data transfer via CD. I'm probably going to get a DVD-R/CD-R/CD-RW soon, even if I hardly ever have to use the DVD-R part.

[Skeptical Greg]

Originally posted by rppa
My $.02




My hard drives are now in the 10s of GB. Backing them up to CD is a really excruciating process that takes a stack of CDs and a lot of babysitting. The medium is expensive. Last time I looked, one recordable DVD was around $30-40 as I recall.



Whoa! When was that?

I just bought a hundred DVD -R ( 8x) for $36..


The new dual layers ( 9gb ) are considered expensive at $5 - $10 each.

You can get good R-W media for $1 a pop.

[rppa]

I just bought a hundred DVD -R ( 8x) for $36..

Guess it's been awhile since I checked. :-) Must have been shortly after they became commercially available. Never bought any.

That sounds like the price I'm paying for CD-Rs at Staples. Hmm.

OK, here's Staples web prices: $20 for a 25-pack of 4.7 GB DVD-Rs
$23 for a 10-pack of DVD-RWs (with jewel case)
$25 for a 50-pack of CD-Rs
$11 for a 5-pack of CD-RWs (with jewel case)

Nothing like the price you quoted (.36 per DVD-R), but it looks like Staples has got them down to close to $1 per DVD-R, half that for CD-R, and that the DVD-RWs are about the same price as the CD-RWs.

I revise my opinion. Time to invest in both the DVD-RW drive and the media. Though I'd still use CD-R and CD-RW for most data transfers.

Either it was a LONG time ago that I looked, or I completely misread some price.

[Skeptical Greg]

Originally posted by rppa

Nothing like the price you quoted (.36 per DVD-R), but it looks like Staples has got them down to close to $1 per DVD-R, half that for CD-R, and that the DVD-RWs are about the same price as the CD-RWs.

I revise my opinion. Time to invest in both the DVD-RW drive and the media. Though I'd still use CD-R and CD-RW for most data transfers.

Either it was a LONG time ago that I looked, or I completely misread some price.


Have to watch for sales at Staples ( and hope you don't have to boter with a mail-in rebate )...


I use Newegg a lot.

http://www.newegg.com/app/ViewProductDesc.asp?description=17-131-039&depa=0

Just bought the NEC 3500 drive there, and the media was on sale for a couple of bucks less.

Granted, these are the budget disks, but I haven't had any bad ones out of the few I have used so far.

Microcenter ( don't know if there is one in your area ) has their house brand 25 packs for around $20, and has them on sale often for $15.

Watch for prices to go down as the 9gb ( dual layer ) disks and drives become more available..

[Art Vandelay]

I wonder if any group will ever release a "box set" on a single DVD instead of forcing their listeners to deal with a bunch of CDs. With compression a group's entire catalog would fit on a single disc.

Originally posted by rppa
Pet peeve: the use of "memory" for permanent storage. "Memory" goes away when the power is off.
How did that get decided?

[Ove]

But it doesn't matter how long you wait... there's an immutable law that says that the simple act of buying a piece of hardware will provoke either an industry price-war or a major technological advance leading to plummeting prices. Me, I refuse to look at adverts or catalogues for three months after splashing out because I know it'll make me depressed.


That is the enevitable "Catch 22" about tecnology.:D But i'd still wait a year, the speed of the burners are growing rapidly.


Edited to add : AND it is not more than ½ a year since i got a CD-burner that i REALLY was satisfyed with.;)

[Badly Shaved Monkey]

Originally posted by HarryKeogh
watch for new generation HighDef dvds and players which will use a blue laser to read the info

I have been since I first read about them a year or more ago. Where are they?

However, I may need to shut my eyes when you post the reply because I have just bought a DVD camcorder and HDD DVD-recorder and, shackled to that technology, I am now frozen into the ancient past of 2 weeks ago while all you young people thrust forwards into the future of rocket shoes, hotels on the moon and 54Gb DVDs.

Having said that, I really like both machines, especially the random access nature of recording to the HDD machine, no more scrabbling around for a tape to record something I might not ever get round to watching and all filed by title. Brilliant.

The camera is really good too, the only annoyance is that my iMac doesn't like the 8cm discs, which is a shame because I had hoped to edit the files on the computer. It's a G4 iMac with a Pioneer DVR-104 drive, in case anyone has wise words to offer on this subject.

[Matabiri]

Originally posted by Badly Shaved Monkey
The camera is really good too, the only annoyance is that my iMac doesn't like the 8cm discs, which is a shame because I had hoped to edit the files on the computer. It's a G4 iMac with a Pioneer DVR-104 drive, in case anyone has wise words to offer on this subject.

Isn't there a Firewire/DV out on the camera? You should be able to plug it in and suck the files straight into iMovie or Final Cut or whatever you want to use.

[Badly Shaved Monkey]

Originally posted by Matabiri
Isn't there a Firewire/DV out on the camera? You should be able to plug it in and suck the files straight into iMovie or Final Cut or whatever you want to use.

Great idea, it's USB only not Firewire, but...no MacOSX USB drivers for the camera. Maybe they'll appear in due course.

[Matabiri]

Originally posted by Badly Shaved Monkey
Great idea, it's USB only not Firewire, but...no MacOSX USB drivers for the camera. Maybe they'll appear in due course.

Have you tried just plugging it in? This works 99 times out of 100 for all devices I've tried on my Mac.

Otherwise it might be worth asking on any reasonable Unix/OSX forum (sorry, can't recommend any), as it's the sort of thing a geek* would probably write for you if asked nicely.

(*The word "geek" is used here in an absolutely non-perjorative way.)

[HarryKeogh]

Originally posted by Art Vandelay
I wonder if any group will ever release a "box set" on a single DVD instead of forcing their listeners to deal with a bunch of CDs. With compression a group's entire catalog would fit on a single disc.

I doubt we'll see it. It seems that when people shell out 50 bucks (or whatever amount) for a boxset they want a lot of disks. Makes them feel like they are getting their money's worth.

I find it annoying that there are so many DVD boxsets (particularly TV shows on DVD) that put a season of shows on 4 or 5 discs when they could fit on 1 or 2.

Guess it also has something to do with shelf space and getting your product noticed.

[Badly Shaved Monkey]

Originally posted by Matabiri
Have you tried just plugging it in? This works 99 times out of 100 for all devices I've tried on my Mac.

This is the 1 in 100, I'm afraid

Otherwise it might be worth asking on any reasonable Unix/OSX forum (sorry, can't recommend any), as it's the sort of thing a geek* would probably write for you if asked nicely.



Good idea.

[rppa]

Originally posted by Art Vandelay
Pet peeve: the use of "memory" for permanent storage. "Memory" goes away when the power is off.

How did that get decided?

Well, it's not the "going-away" part that makes it memory so much as that memory is a fast, random-access storage area that is integrated with the CPU. Running programs are things sitting in memory. A CPU runs an instruction, grabs the next thing in memory, runs that, if the instruction tells it to go somewhere else it goes to THAT place in memory.

In most computers, the thing wired into the CPU this way is usually a bank of RAM chips, which have the property that they use the power supply to keep the state of the 0's and 1's they keep track of. Your computer boots off another memory chip containing read-only memory (ROM) which isn't volatile: it's storage stays when the power goes off.

So maybe it makes more sense to define "memory" as "the addresses used by the CPU". Storage like a disk, a tape, or a CD is something completely different. If you want to run a program stored on one of those things, you have to first copy it into memory. If your program wants to read or write data to those things, it does it by first putting it in memory. Memory is the thing that's directly accessible to the CPU. Storage is indirect and therefore slower.

Memory sticks would seem to blur the issue, since they contain memory chips. But they pretend to be storage. The CPU can't read them directly, it treats them like disks and has to do the same copying through memory that it would in reading any other storage device.

More than you wanted to know.

[Matabiri]

Originally posted by Badly Shaved Monkey
This is the 1 in 100, I'm afraid


Foo!

[Art Vandelay]

Originally posted by rppa
Well, it's not the "going-away" part that makes it memory so much as that memory is a fast, random-access storage area that is integrated with the CPU. Running programs are things sitting in memory.
I'm familiar with the basics, but it's the reason for the nomenclature that I'm wondering about. Is there some clear reason why "memory" is not an appropriate term for storage, or did it just develop that the term was reserved for RAM?

Storage like a disk, a tape, or a CD is something completely different. If you want to run a program stored on one of those things, you have to first copy it into memory. If your program wants to read or write data to those things, it does it by first putting it in memory. Memory is the thing that's directly accessible to the CPU. Storage is indirect and therefore slower.
Is storage slower because it's indirect, or is it indirect because it's slower? If one wanted to build a computer where the CPU directly queries the hard drive, wouldn't that be possible? I thought that the reason this is not done is because it would be so slow, not because it's impossible. And is memory really accessed directly? I thought it's copied to the registers, and processed there.

With processor speed now making it impossible to put RAM within a clock cycle of the CPU, and caches now being larger than the entire RAM of earlier computers, do you suppose that the term "memory" will shift to referring to the cache, and RAM will become "intermediate storage"?

The CPU can't read them directly, it treats them like disks and has to do the same copying through memory that it would in reading any other storage device.I take it than unless a special system is set up, when you network a bunch of computers together, each computer treats memory in every other computer as storage? Is there "virtual storage", a counterpart to "virtual memory"? For instance, if you tryconnecting 5 GB of memory to a 32 bit processer, you wouldn't be able to address the last GB, right?

[El Greco]

Originally posted by Art Vandelay
Is storage slower because it's indirect, or is it indirect because it's slower? If one wanted to build a computer where the CPU directly queries the hard drive, wouldn't that be possible? I thought that the reason this is not done is because it would be so slow, not because it's impossible.

Probably you're right, but the whole architecture is based on the existence of memory. Computers started without permanent storage, so...

Originally posted by Art Vandelay
And is memory really accessed directly? I thought it's copied to the registers, and processed there.

Not necessarily. There are also instructions which directly manipulate memory. Sometimes it's faster, others it's better to copy to a register and proceed from there.

Originally posted by Art Vandelay
With processor speed now making it impossible to put RAM within a clock cycle of the CPU, and caches now being larger than the entire RAM of earlier computers, do you suppose that the term "memory" will shift to referring to the cache, and RAM will become "intermediate storage"?

I think that "memory" will always refer cumulatively to what's lost when there's no power.

Originally posted by Art Vandelay
Is there "virtual storage", a counterpart to "virtual memory"? For instance, if you tryconnecting 5 GB of memory to a 32 bit processer, you wouldn't be able to address the last GB, right?

I'm not sure what you mean by virtual storage. RAM drives could be something like this but generally "storage" is a priori not virtual. With 5GB of memory you couldn't access the last GB directly, but you could map it to some lower memory locations and access it indirectly, something like a selector : offset pair. That is, you could design a system that uses two 32-bit registers for accessing memory.

[RussDill]

Originally posted by Art Vandelay
I'm familiar with the basics, but it's the reason for the nomenclature that I'm wondering about. Is there some clear reason why "memory" is not an appropriate term for storage, or did it just develop that the term was reserved for RAM?


It makes it easier for computer people to communicate if they segment terms out. Memory is really a black box term that refers to a large, flat space where you can store things. It could be implemented via an SPI interface, it could be SRAM, DRAM, mercury tubes, etc.


Is storage slower because it's indirect, or is it indirect because it's slower?


Its slower for physical reasons. Compared to the processing speed of the CPU, and speed at which RAM can be accessed, the hard disk takes a very, very, very long time to make one revolution.


If one wanted to build a computer where the CPU directly queries the hard drive, wouldn't that be possible?


Yes, but it'd be slower. Because the cpu doesn't operate in the time scale of the hard drive, its much better just to put a request into a request queue, have the hardware carry out the requests, and be notified when they are complete. In that way, the cpu can go about its buisness doing other tasks.


I thought that the reason this is not done is because it would be so slow, not because it's impossible.


Many older computers functioned in this way, simply because the OS and hardware was not advanced enough to take advantage of cpu offloading.


And is memory really accessed directly? I thought it's copied to the registers, and processed there.


It depends on the CPU architecture. Many architectures access memory directly (like x86). But modern ones do not, they load registers first. Also, whenever you are accessing memory, you are usually accessing a cacheline that is loaded with that memory.


With processor speed now making it impossible to put RAM within a clock cycle of the CPU


Actually, no, older processors, the cpu and ram functioned at the same clock speed. But with modern processors, the cpu functions at a much, much higher speed. When any access is made, the processor bursts a larger amount of data from the RAM into cache, then, when more data is accessed, the data will hopefully already be in the cache.


and caches now being larger than the entire RAM of earlier computers, do you suppose that the term "memory" will shift to referring to the cache, and RAM will become "intermediate storage"?


naw, like I said before, memory is really a programmers definition, they don't care how its implemented.


I take it than unless a special system is set up, when you network a bunch of computers together, each computer treats memory in every other computer as storage?


afaik, distributed NUMA (non-uniform memory architecture) systems exist.


Is there "virtual storage", a counterpart to "virtual memory"? For instance, if you tryconnecting 5 GB of memory to a 32 bit processer, you wouldn't be able to address the last GB, right?

Virtual memory is the amount of memory in your memory map. When you load a program, or file, it is mapped into virtual memory. If you don't have enough RAM to hold it, thats fine, it just pages from the disk when it needs certain parts of the file. Swap is done in a similar fashion. Thus, the 4GB limit becomes a problem even if you don't have 4GB of ram, because you virtual memory is limited to 4GB.

Using more than 4GB (or 3GB, depending on the architecture layout), is usually done by giving each individual process a 4GB memory map.