Re: Hard disk speed - Maybe OT

Hi Will

Yes it may have been us talking about camera stuff!

At the sake of possibly repeating myself, we bought two camera types from Trendnet, both wireless but one a steerable ball model. They are however vastly different in performance and quality. The steerable model has an atrociously bad definition image compared to the fixed one. They never appear sharp at all. (They are both 640x480) The steerable one however does MJPEG and if you use its FTP client you can send about 4-5FPS to a server. The fixed one however will only do about 0.7FPS in ftp client mode and streaming is done by sending multiple http auth/gets with different source ports rather than just reusing the one. The camera then sends back complete jpg's not mjpeg. Wget presents the same problem. ie if I just try to grab one URL at a time and loop it I cant get any faster than the 0.7FPS. If however I give it a list of 100URL's from a file it will do maybe 8-10FPS.

This for me has actually been quiet interesting as it is a non profit/no pay project. If I was doing it for money I'd be real upset!

Yep I remember XT's and ST225's! I however cut my teeth on a PDP11-44 <grin>

I originally went to a ramdisk to reduce latency but I can see your point now that using RAM for this instead of cache isnt so good. It is no biggy changing the script as I did my initial work w/out a ramdisk. I actually now wonder whether "free" includes a ramdisk size in "buffers".

You're right too, I have never seen any linux tools for checking disk cache hits. In a case like mine it would be handy to say "always keep these files in cache" like those you mentioned (libraries etc). When working with moving files around once it is hardly worth caching them for a later read too. It is however handy to queue them up for one write. (My thoughts on using the elevator code)

As it turns out I just acquired another P3/900 to rebuild for resale at the thrift store.. It has 512MB of RAM so I can swap that with the processor machines. I also came up with a method to avoid the file/timestamp renaming process. Kind of bad to make three changes at once, but if it works I'll be happy.

Shall do some more work and get back to you with the results. Thanks for your input.

OBTW do you know of any NFS limitations do do with large directories of files? I am nowhere near the 750,000/directory Reiser limit. Probably around 450,000 maximum.

Bob

PS My NG email address is valid if you want specific details on the system.

Will Honea wrote:


I'm with Nick - I read what I expected instead of what you wrote. Now I'm a
bit suspicious as well, even with you expanded explanation but before we
get too far gone I'd sure like a better look at what you are doing here
.