Date: Fri, 18 Apr 1997 12:21:16 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: dufault@hda.com (Peter Dufault) Cc: hasty@rah.star-gate.com, terry@lambert.org, freebsd-hackers@freebsd.org Subject: Re: video capture driver interface to file system? Message-ID: <199704181021.MAA08439@labinfo.iet.unipi.it> In-Reply-To: <199704181001.GAA16977@hda.hda.com> from "Peter Dufault" at Apr 18, 97 06:00:58 am
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> Pre-allocate the file; pre-allocate the blocks of a file; pre-set > up some control info for a transfer, mmap a set of blocks for the > video card driver to dump data into; have the driver chain to the > next block and interrupt you on each transfer, dump the video frames > to the pre-allocated store. and probably, in addition to preallocation, make sure that your write() calls are aligned to the FS/device blocksize otherwise (probably) each write will be preceeded by a hidden read to take care of fragmentation ? Luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________
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