DeadHead@cup.portal.com (Bruce M Ong) (02/28/89)
Hi - I am working on a pc-interface project which accumulates a lot of data really fast in a ram buffer (DS:offset to DS:FFFF). I need to write this buffer to an opened DOS file using DMA. Does anybody know which DOS software interrupt or system call I should use to accomplish this? I need to flush this buffer quickly. (the buffer could be as large as 60K). If there is no such system call via int 21 or software interrupt, what should one do so that the DMA write operation will not by-pass and screw up the DOS file system? I checked the BIO listing and couldnt figure it out (the fixed disk bios listing has virtually no comments in it) Thanks. Please reply in E-Mail as I do not check this group very often... Bruce
james@bigtex.cactus.org (James Van Artsdalen) (03/03/89)
In <15182@cup.portal.com>, DeadHead@cup.portal.com (Bruce M Ong) wrote: > I am working on a pc-interface project which accumulates a lot of > data really fast in a ram buffer (DS:offset to DS:FFFF). I need to write > this buffer to an opened DOS file using DMA. Most AT disk controllers don't support DMA. That's because DMA is slower than programmed I/O on the IBM architecture. It's faster to use "rep outsw". -- James R. Van Artsdalen james@bigtex.cactus.org "Live Free or Die" DCC Corporation 9505 Arboretum Blvd Austin TX 78759 512-338-8789