[Info-vax] TK50 - this is annoying...

JF Mezei jfmezei.spamnot at vaxination.ca
Tue Oct 9 17:38:56 EDT 2012


>> But I too have not heard of anyone actually doing this kind of 
>> semi-interleaving. Most machines I've seen or used don't have a problem 
>> keeping the DECtape running at full speed across several blocks.


Backup did have problems keeping the TK50 busy on the all mighty
Microvax II.  This is part of what made ir so slow because the TK50
would constantly start and stop, with each start taking forever due to
tape positioning.

In one of the 5.* releases, DEC made major improvements to Backup which
had long pauses to collect data followed by the writing of much larger
quaktities of data at once (as opposed to reading from disk, writing to
TK50, reading from disk, writing to TK50 of the past). This made a HUGE
difference is performance (and I beleive (but not sure) also greatly
reduced wasted tape due to fewer interblock gaps.



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