Reading from 8mm tape
scott andrew marr
marr at cup.portal.com
Thu Jul 26 09:09:25 AEST 1990
I am have a project where it is necessary to read, as fast
as possible, large amounts of data from 8mm tape,
using a DECstation 3100. The data is stored on the tape by
a real time data aquistion processor in 1K blocks.
I have been able to open the device and read from it using the
standard UNIX system calls (open & read). The problem is that I
can only read 1 block per call, and the cycle time between two
reads is around a second. The data on the tape is hundreds of
megabytes long, so the operation is unreasonable.
Does anyone know of a way to get more than just one block per
read? The only thing I've come across is using something called
a nbuf facility (via ioctl) that implements multiple buffers,
but I'm not sure what that will do for me (or to me!). Any
suggestions would be appreciated.
____________________________________________________________________________
| marr at cup.portal.com
Scott Marr | or
| marr at decster1.msd.lmsc.lockheed.com
____________________________________________________________________________
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