Geek question: Memory cards versus DVDs

[danaeris]

So, I'm comparing DVDs to various memory card technologies, and the more I look at them, the more it looks to me like the memory cards are, in the long run, a potentially superior technology.

They seem capable of similar capacities to that of DVDs (possibly more), they are less vulnerable to, for instance, scratching, and some are capable of writing at least as fast as DVDs, and certainly faster than the new HD DVDs and BluRay DVDs, if I'm reading my number right. And, they're smaller and thus more portable.

So, why aren't they replacing the DVDs? Is it because they are less permanent?

Comments

[pyat.livejournal.com]

That, and because DVD players will play the CDs everyone likes.

[aaangyl.livejournal.com]

A 1G flash memory card is still in the $40-50 range even bargain hunting. A DVD is a few bucks and holds 4G. The microdrives are also still quite expensive. I find there's a place for each - I use flash cards where I used to use re-writable CDs or DVDs, but I still burn off data for archival as well as backing it up to another hard drive.

DVD vs. flash memory

[http://users.livejournal.com/_duncan/]

Yeah, what she said. I use the little 256MB thumbdrives for getting installation binaries and OS updates to people on dialup but they aren't cheap.

They seem capable of similar capacities to that of DVDs (possibly more)
If I didn't see the paragraph before this I'd have guessed you were thinking of CDs, Dana. Perhaps you have a line on some really big flash cards I've not seen offered locally?
CD: 800MB (beyond the capability of some drives).
DVD: 4.7GB or 9GB (single vs. dual layer).

Is it because they are less permanent?
A filesystem on a memorystick is much more vulnerable to corruption after creation than one on a DVD. Unless writing is blocked by a physical switch setting (some have one) then every read may be immediately followed by a write to update the last access time. A true zero-current flash memory cell has a lifespan measured in write cycles. A not-quite-compliant port controller may be unable to meet the stick's current requirement yet willing to run it without raising an error flag. That or a cheap USB hub may provide too little voltage for reliable operation or may overdrive the stick. A misbehaving system may misread it as blank, steal focus from another app and interpret your next keystroke as permission to format the volume.

there's a place for each
Yup.

Re: DVD vs. flash memory

[aaangyl.livejournal.com]

You know what I'd dig? Some little device that let me use old machine RAM as a flash drive. I have TONS AND TONS of 128M-1G simms, dimms, you name it that just sit there useless once the boards that supported them are retired.

hardware RAM disks

[http://users.livejournal.com/_duncan/]

You know what I'd dig? Some little device that let me use old machine RAM as a flash drive.

You're looking for something like the Rocket Drive (http://www.cenatek.com/product_rocketdrive.cfm) but sold without the 4G of RAM and preferably with some onboard storage of electrical power and with continuously charged battery plugged into its external DC port. Cenatek is a California company.

Another company named Gigabyte makes the i-RAM (http://www.tomshardware.com/storage/20050907/gigabyte_iram-01.html) card which will turn up to 4GB of DDR ram into a ramdrive. Unlike the card above this one has a battery but lacks a DC input jack. If the PC remains unpowered for 16 hours the contents are lost. This strikes me as really stupid. The card has a SATA port on it. It would seem trivial, given a SATA port and a battery, to write the ramdrive contents to the magnetic media on or shortly after powerdown. As it turns out, this card uses the PCI connection only for power, uses the SATA for data I/O with the system and has no connection to a traditional drive.

HyperOS (http://www.hyperossystems.co.uk/) makes the "HyperDrive III" which sounds like a drop-in drive replacement. It takes DDR RAM and its battery life is 2.5 hours. A software component watches for a powerfail signal from an external UPS and backup to another drive in the system. They're based in England.

I remember seeing something much closer to what you describe. It was made in Australia and had some animal as its product name but it isn't coming to me.

Instead I get hits on super-souped-up jobs like the RamSan-120 (http://www.superssd.com/products/ramsan-120/indexb.htm), a rackmount FiberChannel hardware ramdrive with internal batteries and magnetic backup storage and with RAID between the memory modules to protect against failure.

Ahh, got it: Platypus Technology: QikDRIVE (http://web.archive.org/web/20040210062616/www.platypus.net/products/qikdrive.asp). They've gone under but the hardware may still be in circulation. Page 23 of 27 in the Platypus marketing presentation (http://web.archive.org/web/20030309144403/platypus.net/Platypus_web_presentation.pdf) includes a few pictures of the product line. Those, I believe, take standard DIMMs.

[angelkatharine.livejournal.com]

DVDs are much cheaper to mass produce with data on them?

user writable CDs are under 6 cents each in quantities of 100 now; DVDs probbly aren't far behind. I doubt we will see 1 GB memory cards for 6 cents any time soon...

[angelkatharine.livejournal.com]

This was actually polkamadness.

[nathanjw]

Mass production of prerecorded materials is a big deal. That DVDs can be stamped out from a master for a price of (I think) less than a dollar for 4-8GB of material is worth a lot. A great deal of the computer storage on DVDs is subsidized, in effect, by the infrastructure that exists for manufacturing and selling movies on DVD.

DVD-Rs are something like $0.20 per gigabyte; memory cards, today, are something like $40 per gigabyte. Memory cards do have physical durability going for them, but the price difference is so steep that you can be massively redundant instead of robust and still be a lot cheaper.

As for the grand question of what the future of storage will bring... there are too many competing options. Maybe it'll be flash, maybe it'll be something new and solid-state, maybe tiny hard drives will take the lead again. The history of storage doesn't really support the idea that a single technology will ever have the reign for very long.

[lousy-timing.livejournal.com]

Yep- I've had the data on my memory card corrupt fairly easily, and it can be ever so slight. With a Quicken backup file, for example, it was missing just a single bit of work that had been saved to it, but when you're looking for a check you KNOW you entered, that's pretty scary.

[wingygoth.livejournal.com]

From what I've read, there is some debate over which HD technology is going to go to the consumer market (right now there's a debate similar to VHS v. Beta). I think the industry may be reluctant to completely change formats simply because everyone now owns a DVD player. Eventually, we will watching everything on our computers, anyway, at which point flash drives and such may make more sense. The move is towards smaller and smaller technologies with larger and faster capabilities, and at some point, the DVD format will be rendered obsolete, just like everything else.

I was in a friend's car the other night and he had mixed tapes. It took a few seconds to remember what they were. Funny, huh?

[nathanjw]

The format battle shaping up is HD-DVD vs. Blu-Ray. It's going to suck. I don't think HD is compelling enough to make lots of people switch, the way that DVDs almost totally took over from VHS, so it's going to be a long, slow battle. I suspect that "regular" DVDs will still be around until something comes along to blow away 5" optical discs entirely.

[unseelie23.livejournal.com]

Combo Blu-Ray/HD-DVD is likely what will happen, just like DVD+R and DVD-R.

[angel-thane.livejournal.com]

Do you have a lead on that? From everything I've been hearing, the hardware for the formats are mutually incompatible, and the only way you could do a combo blu-ray/hd-dvd would be the same way they currently have combo VCR/DVDs - ie have two slots in one machine.

[unseelie23.livejournal.com]

No leads, just a number of people I know in the industry saying that it's inevitable.

[karenbynight.livejournal.com]

Cost.

They are replacing DVDs for some uses, but not for others. There are three distinct uses of portable media: making data portable so you can use it in multiple places and/or transfer it; copying data for personal backups; and copying data to share with others.

The latter two uses, you want the media to be as cheap as possible, and you don't care if it is reusable. This is not the case with the former.