Good deal for OSD owners on 8GB SDHC cards -> CF in OSD is faster than USB
Fernando Cassia
//////
Q: Should I use CF or USB for OSDng storage?
A: CF is much faster than the USB on the OSD.
//////
Well, if the CF slot is much faster than the USB slot, then it makes no
sense to use USB thumb drives... IMHO the cheapest solution for OSD 1.0
owners is to buy one of these adapters....
...that plugs into a CF slot, and accepts SD/SDHC cards...
Then buy a handful of 8GB SDHC cards which are cheap as chips....
$13 8GB SDHC card(s)
http://bit.ly/8gbsdhc
The advantage here is that:
1. It'd be faster than an equal number of 8GB Pen / thumb drives
accessed through the USB port
2. You can re-use the 8GB SDHC cards on your digicam when need arises,
which beats buying 8GB+ CF cards that very few digicams use nowadays.
3. An eight-GB CF card is between $25 and $30 a piece, vs. $13 for each
SD card which you can insert on the above mentioned adapter....
Just my $0.02...
FC
bmc
Yep, SD/SDHC in a CF Type 2 adapter work fine under the OSD for me.
The cheap one I have ($15 w/ free shipping off of eBay) is a little
slower than a "real" CF card, but:
a) SD/SDHC cards tend to be cheaper and larger capacity than CF cards
nowadays
b) the SD slot doesn't work as root storage under OSDng at the moment
c) the native SD slot routines are slower on the OSD than the CF slot
routines.
I'm thinking a newer kernel and/or drivers could fix b) and c), but
don't know that I or anyone else will get to it.
For the record, my quick 'n' dirty time trials show:
USB:
read 10M ~ 16sec
write 10M ~ 16sec
SD:
read 10M ~ 4sec
write 10M ~ 30sec (!)
CF
read 10M ~ 1sec
write 10M ~ 4sec
SD-inside-CF adapter (same 2GB SD card as above)
read 10M ~ 3sec
write 10M ~ 8sec
The bogus benchmarks used were:
$ swapoff ...
$ bash
$ sync ; time ( dd if=/dev/zero of=test bs=1M count=10 ; sync ) #
write
$ time (dd if=test of=/dev/null bs=1M count=10) # read
With 2.6.15, there's no nice kernel interface to dump caches, but the
OSD has so little memory free that I don't think there's many cache
effects in the above numbers.
On Jun 15, 12:27 pm, Fernando Cassia <fcas...@gmail.com> wrote:
> The OSDng FAQ athttp://osd.oddren.com/#faqreads:
> //////
> Q: Should I use CF or USB for OSDng storage?
>
> A: CF is much faster than the USB on the OSD.
> //////
>
> Well, if the CF slot is much faster than the USB slot, then it makes no
> sense to use USB thumb drives... IMHO the cheapest solution for OSD 1.0
> owners is to buy one of these adapters....
>
> ...that plugs into a CF slot, and accepts SD/SDHC cards...
>
> Then buy a handful of 8GB SDHC cards which are cheap as chips....
>