Why 16 gig so cheap?
- Thread starter DavidBeier
- Start date
Barry_Green
Moderator
The 8 started out initially announced at $2750 in November 2005, then by the time it was first actually marketed it had dropped to $2200. Then sometime around Feb or so it dropped to $1400. Then I think it was about NAB time that it went to $1200, and then at this NAB it went to $700. So it dropped to 1/4 its price over the last 18 months or so.
Ok, I know it already been covered, but lemme explain...
Look at the price curve for SD memory cards.
Look at how many it takes to make 16 GB or 32 GB.
Watch the price curve go down! (Over time, the memory becomes cheaper.)
(Insert Jan's explanation about the difficulty in making 8 GB cards here)
Now, basically, a P2 card has to have almost flawless memory. A few bad transistors can make an entire piece of memory unwriteable. In a computer, or digital still camera, your system's memory controller compensates for this by writing that chunk to the next good piece of memory. It works, but it means the meory access is a little bit slower.
Now, SD memory is much much slower for writing than RAM in a computer- so a bad chunk slows down that write even more. the larger the bad chunk, the more the write is slowed. You could end up very easily with a P2 card with bad chunks on a bunch of different cards that slowed the writing time (both the access time and real write time) below the 100 mb/s that these card must maintain (hence why they have to use level 7 memory). To get their data rates, Panasonic is using custom LSI logic that turns those multiple chips of SD memory into a sort of RAID, where it is striping the data across multiple chips simultaneously. And most of you probably know what happens when you get a bad hard drive sector in a RAID- speed loss. The P2 cards are more than likely designed to be able to compesate for a certain number of bad pieces of memory (sectors) and the LSI chips probably have to keep track of these bad sectors to make sure the data isn't lost (a RAID controller for hard drives should do this as well) so that if the memory develops bad sectors over time (SD memory does wear out, but it takes millions of read/write cycles) it can keep maintaining the data rates. If they used level 5 memory, the card would cost much much less, but the card wouldn't be nearly as reliable and would wear out faster. Acceptable for a thumb drive, but not for a professional recording format that is trying to be more robust than tape.
For those still trying to understand- this is really simplifying the problem- but look at the difference between cheap system memory and premium workstation memory. (Yes, i know, oversimplification, but...)
Btw, I remember paying $700 for a 16 MB stick of memory to go into my '040 Amiga 2000.
Look at the price curve for SD memory cards.
Look at how many it takes to make 16 GB or 32 GB.
Watch the price curve go down! (Over time, the memory becomes cheaper.)
(Insert Jan's explanation about the difficulty in making 8 GB cards here)
Now, basically, a P2 card has to have almost flawless memory. A few bad transistors can make an entire piece of memory unwriteable. In a computer, or digital still camera, your system's memory controller compensates for this by writing that chunk to the next good piece of memory. It works, but it means the meory access is a little bit slower.
Now, SD memory is much much slower for writing than RAM in a computer- so a bad chunk slows down that write even more. the larger the bad chunk, the more the write is slowed. You could end up very easily with a P2 card with bad chunks on a bunch of different cards that slowed the writing time (both the access time and real write time) below the 100 mb/s that these card must maintain (hence why they have to use level 7 memory). To get their data rates, Panasonic is using custom LSI logic that turns those multiple chips of SD memory into a sort of RAID, where it is striping the data across multiple chips simultaneously. And most of you probably know what happens when you get a bad hard drive sector in a RAID- speed loss. The P2 cards are more than likely designed to be able to compesate for a certain number of bad pieces of memory (sectors) and the LSI chips probably have to keep track of these bad sectors to make sure the data isn't lost (a RAID controller for hard drives should do this as well) so that if the memory develops bad sectors over time (SD memory does wear out, but it takes millions of read/write cycles) it can keep maintaining the data rates. If they used level 5 memory, the card would cost much much less, but the card wouldn't be nearly as reliable and would wear out faster. Acceptable for a thumb drive, but not for a professional recording format that is trying to be more robust than tape.
For those still trying to understand- this is really simplifying the problem- but look at the difference between cheap system memory and premium workstation memory. (Yes, i know, oversimplification, but...)
Btw, I remember paying $700 for a 16 MB stick of memory to go into my '040 Amiga 2000.
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