Hi, Kenneth!
Trying to kill the keyboard, Kenneth M. Howlett
([EMAIL PROTECTED]) produced 4,5K in 119 lines:
> It seems to me that shoeshining (the tape keeps going back and
> forth, back and forth, back and forth) occurs when the computer
> can not transfer data to or from the tape drive fast enough.
Ack.
> transferring it, and the processing is the slow part,
Or the searching on the HD, especially if the I/O channel is
flooded with requests from other programs.
> Instead, create a
> spooling buffer. Let the archive program transfer data into the
> spooling buffer as usual. Wait until the spooling buffer fills,
> and then transfer the whole spooling buffer at once.
ftape uses per default 3 DMA buffers a 32 K to do this. Also
man buffer.
> To read the tape:
> perl -e 'while(read(STDIN,$A,[spool buffer size]))
> {print($A)}' < [tape device] | [read archive from STDIN]
In that case it won't be as bad: uncompressing's faster than
compressing the data.
> If you are using swap memory, then part of the spooling buffer
> might be swapped; you might be able to speed
> up access to the spooling buffer by turning swap off.
If you are using that much buffer, you are doing something
wrong. Just be sure to (re)start the tape when the buffer is
nearly full. buffer -p 85 does that well.
-Wolfgang
