Need more than 6.2Mb/sec from UW scsi

“Bill Caroselli (Q-TPS)” <qtps@earthlink.net> wrote in message
news:9m0foo$jci$1@inn.qnx.com

Hi Phil

If you need a large ramdisk on the fly look at the vdir utility in the
latest distribution of QNX.

vdir is VERY slow with big files it’s actually much slower
then a harddrive. It wasn’t made to handle big files.
That was the first release of vdir, it may have chance since then.


Bill Caroselli

“Phil Olynyk” <> pholynyk@home.com> > wrote in message
news:> 3B83BDB1.68A6B16B@home.com> …
Hi Erick -
Sorry this has been delayed, I got sidetracked by some other
suggestions.

Trying to specify -F 1 gives me the same result as trying any other
aha8scsi option:
Error processing arguments for ‘aha8scsi’ module

So, clearly, I don’t know how to specify options! And no one has given
any
suggestions that amplify on the documentation…

Since there seems to be a huge cache on a 256Mbyte system, I will write
a
simple program to make a big /dev/shmem/foobar.dat, since I don’t really
want
to build a new .boot file for a big ramdisk. I think I will need to make
my
foobar.dat about 80Mb large. I will try various sizes to see if I can
determine a lower bound on long transfers. This will have to wait until
I
get
back to the client site, probably tomorrow.

Thanks - Phil Olynyk

Hardware Support Account wrote:

Hi Phil,

What happens if you specify -F 1

Could you post the output of cp -V to and from either /dev/shmem
or a ram disk?

Thanks

Erick.

Phil Olynyk <> pholynyk@home.com> > wrote:
Hi all -
I am working on a project which involves saving video to a UW
scsi
drive - the AHA2940UW controller and the Cheetah drive both claim to
be
capable of 40Mb/sec in sync mode. I’m using blockwrite() in a loop
to
write out 513 blocks, 127 at a time. I need to do this for more than
a
minute or two… So far my sustained rate over 20 to 40 seconds is
6.2
Mb/sec, which is the async transfer rate, as far as I can tell from
the
Seagate doc.
Using the latest ( 6 Feb 01 ) Fsys.aha8scsi, I have been trying
to
force sync, wide, and ultra using -S 1 -W 1 -U 1 after the aha8scsi
option - but I get an error message about processing options for the
aha8scsi module — it won’t even take a -v or -vvv to tell me what
it
thought it was doing! When I use Fsys.aha7scsi and its options, they
are
accepted, and nothing changes > :frowning:

SO… can anyone tell me how to set options for Fsys.aha8scsi so
that
I can get a transfer rate of at least 10 or 15 Mb/sec?
And/Or how to use open() and blockwrite() to bypass a driver
cache
and DMA straight from my buffer out to the drive?
Or any other useful ideas? ioctl()s for the driver ?? new in
4.25E
includes maybe ( I only picked up the scsi driver )

Thanks -
Phil Olynyk
OBT Software Corp.

OK. I never tried using it on large files. It was just very convienent to
use for me.

Bil Caroselli

“Mario Charest” <mcharest@remzinformatic.com> wrote in message
news:9m1khr$am7$1@inn.qnx.com

vdir is VERY slow with big files it’s actually much slower
then a harddrive. It wasn’t made to handle big files.
That was the first release of vdir, it may have chance since then.