Wednesday, November 02, 2011

When is an SATA drive not a drive, when it's compact flash

The CompactFlash Association  has released the new generation of the CF specification, CFast™ [from a piece on 100MB/sec CF cards]
10-15 years ago, CF cards were used almost exclusively in all Digital cameras, now they are used only in "high-end" Digital SLR's (DSLR), presumably because of cost/availability compared to alternatives like SDHC cards.

The UDMA based CF standard allows up to 133MB/sec transfer rates.
The new SATA based standard, CFast, allows 3Gbps (~300MB/sec) transfer rates.

In another context, you'd call this an SSD (Solid State Disk), even a "SATA drive".
There are two problems:
  • common cameras don't currently support CFast™, the SATA based standard, and
  • 'fast' CF cards are slower than most SSD's and attract a price premium of 5-10 times.
I'm not sure what decision camera manufacturers will make for their Next Generation high-end storage interface, they have 3 obvious directions:
  • CF-card format (43×36×5 mm), SATA interface, CFast™
  • 1.8inch or 2.5inch SSD, SATA interface
  • 34mm ExpressCard. PCIe interface.
and the less obvious: somehow adapt commodity SDHC cards to high-performance.
Perhaps in a 'pack' operating like RAID.

The "Next Generation Interface" is a $64 billion question for high-end camera manufactures, the choice will stay with the industry for a very long time, negatively affecting sales if made poorly.

Manufacturers are much better off selecting the same standard (common parts, lower prices for everyone), but need to balance the convenience of "special form factors" with cost. Whilst professional photographers will pay "whatever's needed" for specialist products, their budgets aren't infinite and excessive prices restrict sales to high-end amateurs.

Perhaps the best we'll see is a transition period of dual- or triple-card cameras (SDHC, CF-card and CFast™), with the possibility of an e-SATA connector for "direct drive connection".

Update 04-Nov-2011:
Here's a good overview from the Sandisk site of form-factor candidates to replace the CF card form-factor of (43×36×5 mm):

SanDisk® Solid State Drives for the Client
 "A variety of form factors, supporting multiple OEM design needs."

SanDisk® Solid State Drives for the Client
Product NameInterfaceForm FactorMeasurements
SanDisk U100 SSDSATA2.5"100.5 mm x 69.85 mm x 7 mm
std allows 9.5mm, 12.5mm, 15mm
SanDisk U100 SSDSATAHalf-Slim
54.00 mm x 39.00 mm x 3.08 mm (8-64GB),
x 2.88 mm (128-256GB),
Connector 4.00 mm
SanDisk U100 SSDSATAmSATA30.00 mm x 50.95 mm x 3.4 mm (8-64GB),
x 3.2 mm (128-256GB)
SanDisk U100 SSDSATAmSATA mini26.80 mm x 30 mm x 2.2 mm (8GB),
x 3.2mm (16-128GB)
SanDisk iSSD(TM)SATASATA uSSD16 mm x 20 mm
x 1.20 mm (8 GB-32 GB)
x 1.40 mm (64 GB)
x 1.85 mm (128 GB)
Standard 1.8 in
SATA1.8"54 mm x 71 mm x 8 mm
Express Card PCIeExpress
34mm x 75 mm x 5mm
54mm x 75 mm x 5mm
Compact FlashATACF-II36mm x 43 mm x 5mm

No comments: