Magnetic tape filesystem

Mike Stein mhs.stein at
Mon Feb 9 13:31:33 CST 2015

----- Original Message ----- 
From: "Chuck Guzis" <cclist at>
To: <General at>;
"Discussion at and Off-Topic
Posts" <cctalk at>
Sent: Monday, February 09, 2015 1:40 PM
Subject: Re: Magnetic tape filesystem

> All this talk about magtapes brought some
> memories to the fore.
> While a single tape drive was the rule for
> personal computers, it certainly wasn't that way
> for mainframes.  In particular, one very
> important aspect was sorting (and, by extension,
> merging).  The wonder of a polyphase (or better
> yet, oscillating) sort running on a bank of 8
> 300 ips drives was mesmerizing.
> Undoubtedly, the folks before me who spent their
> time shuttling trays of punched cards around an
> IBM 082 have a similar reaction to the
> "easiness" of tape sorts as compared to card
> sorts...
> --Chuck

----- Reply -----

... especially when you tripped and dropped a
stack of sorted cards on the way to the collator
or 403...

Was just leafing through documentation on using
cassettes in Burroughs L systems:

" It is possible to sort data by using 3 or 4
magnetic tape stations ...
_However, this is a slow operation and it is not
advised that magnetic tape cassettes are used in
this way._"

Sorting 900 records of 256 bytes on a 512 word
base memory machine with three drives took 1 hour,
41 minutes. Increasing memory up to 1536 words and
adding a fourth drive brought that down to a mere
55 minutes!

But these were different times where life moved
more slowly. I actually designed several systems
using four cassette drives and magnetic cards, and
one or two days every week you just set aside an
hour or two for sorting and housekeeping.

And on the other hand,:
"A cassette is easily transportable from one site
to another compared to a disk. Drop a disk on the
floor and the chances are that it can't be used

Now, sorting using paper tape, that oughta be


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