Re: high speed data file playback

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Scott McMillan (scott++at++ht.com)
Wed, 4 Dec 1996 15:43:32 -0500 (EST)


> If I wish to replay data from a hard-drive what is the preferred command for
> opening and reading the data-file for maximum performance. The machine will
> be either a Max Impact or Infinite Reality (probably IR)? How much could be
> read in a 20th of a second?
> Jeffry J. Brickley

Depending on how much data you are talking about the following may or may not
be a viable alternative:

When I was doing this for real-time playback of a dynamic simulation that
would take hours to complete, the simulation would output the state to a file
every 20th of a second, and when it came time to do a playback, I would read
ALL of the data into memory first and then step through the data 1/20th a
second at a time. That way I wouldn't have to worry about disk access
affecting frame rate, except for virtual memory swaps which I don't think
ever happened in my situation. The state of my system wasn't too large
(about 50 floating point numbers per frame) and I had the memory to burn.

> ===============================================================
> Jeffry J. Brickley jbrickley++at++lmwsmr.lesc.lockheed.com
> 3D Systems Programmer for Lockheed Martin, White Sands Missile Range
> ===============================================================
> Dedicated to pushing the limits of any SGI I'm given....
> ===============================================================

Me too...

scott

-- 
  Scott McMillan  |       HT Medical, Inc.      | Developing virtual environ-
   scott++at++ht.com   |      http://www.ht.com      | ment medical and surgical
 Ph: 301-984-3706 | 6001 Montrose Rd., Ste. 902 | simulations and surgery
Fax: 301-984-2104 |     Rockville, MD 20852     | simulation creation tools.

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