Arthur> It's all buffer dependent. Early 4000s didn't have enough Arthur> buffer to do this. If you're draining the buffer, then you're Arthur> not sending data fast enough. So the drive needs to be able Arthur> to buffer data at tape speed for long enough to go through a Arthur> stop,rewind,start cycle. I've never noticed any real penalty Arthur> on a 7000. Their buffers seem to be large enough to not have Arthur> the tape slow down the machine..
The early DLT 7000s also had this problem, since they came with a 4 MB buffer on the drive. At full speed data rates, this wasn't enough to keep the drive from throttling the sender in certain cases.
The current 7k drives all have 8Mb buffers, which let's them hold enough data if they have to re-wind and get back upto speed. That takes about 1.5 seconds to do.
My reference is the "DLT University Handbook".
John John Stoffel - Senior Unix Systems Administrator - Lucent Technologies stoffel@lucent.com - http://www.lucent.com - 978-952-7548 john.stoffel@ascend.com - http://www.ascend.com