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From: envbvs@epb2.lbl.gov (Brian V. Smith)
Newsgroups: comp.sys.dec
Subject: Re: TK-70 vs. reel-to-reel storage
Message-ID: <2730@helios.ee.lbl.gov>
Date: 26 May 89 16:26:23 GMT
References: <51900@aerospace.AERO.ORG>
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In article <51900@aerospace.AERO.ORG>, sinclair@aerospace.aero.org (William S. Sinclair) writes:
> 
> I am puzzled by the difference in storage capabilities between the two.
> The little TK-70 can hold 296 MB of data, as compared to only 140 MB
> for the reel-to-reel at 6250 BPI. Some simple computations reveal that
> the reel-to-reel has about TWICE the media storage area. So assuming that
> both storage technologies are about state-of-the-art, why can't the 6250
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Why do you make this assumption?  6250 tape drives have been around for
more than 10 years.  That is dinosaur technology.
What is surprising is that nobody has produced a reel-to-reel drive of 
higher density by now.

> BPI reel-to-reel hold about twice as much, rather than only half?
> The TK-70's are 600 feet long by 1 inch wide, which is 7200 sq. inches,
                                   ^^^^^^^^^^^
Sorry, they are 1/2 inch wide (HI/TC, another name for these drives,
means half-inch tape cartridge).

> while the reel-to-reels are 2400 feet by 1/2 inch wide= 14400 sq. inches.
> 
> Bill S. 

_____________________________________
Brian V. Smith    (bvsmith@lbl.gov)
Lawrence Berkeley Laboratory
We don't need no signatures!