[SIGCIS-Members] New biggest hard drive candidate: Librascope Disk File

[Chuck House]

I interviewed Les in that same room.    I think that disc is a fixture for his lifetime

 

Chuck House 

www.innovascapesinstitute.com 

www.anywhereanytime.io/covid19 

 

 

http://innovascapes.blogspot.com

805-570-6706

 

 

 

From: Members <members-bounces at lists.sigcis.org> on behalf of Salem Elzway <salem.elzway at gmail.com>
Date: Monday, September 21, 2020 at 10:30 AM
To: <members at sigcis.org>
Subject: Re: [SIGCIS-Members] New biggest hard drive candidate: Librascope Disk File

 

Hi everyone,

 

Les Earnest, former executive director of SAIL, uses the only existing (?) Librascope Disk File for a coffee table in his living room (see the image in the SAIL ebook Tom linked to).  That is, assuming he hasn't gotten rid of it since I interviewed him at his home last February (2019)...

 

Best,

Salem

 

On Mon, Sep 21, 2020 at 11:49 AM <thomas.haigh at gmail.com> wrote:

Hello SIGCIS,

 

My new candidate for largest hard drive is the Librascope Disk File, as used at SAIL. According to this letter from Ed Feigenbaum, only two were produced. Stanford acquired one of them for $300K in 1967, but a year later a “massive malfunction” destroyed half of its capacity, leading to a lawsuit settled out of court. In 1976 it was decommissioned, but at least one of the platters was saved and displayed. https://exhibits.stanford.edu/feigenbaum/catalog/ct397kv6234

 

According to these pictures of the display, http://infolab.stanford.edu/pub/voy/museum/pictures/display/1-MD-MemDisk2.htm it was a “head per track” unit (i.e. more like a flat drum memory than a regular disk) which would solve the problem of large access times moving a head over such a large disk. The overall drive had six platters and weighed 5,200 lbs, to store 1,120,665 32-bit words (ie about 4.27MB) per side. So about 50MB total. 

 

An exhibit page at CHM documents what seems to be a platter from the same drive, claiming a 5 foot diameter (i.e. approx.. 60 inches). https://www.computerhistory.org/collections/catalog/102682858

On the other hand, an ebook about the SAIL DART archive gives a 4 foot diameter (i.e. approx.. 48 inches). https://www.saildart.org/simple/booklet/SAILDART_PREVIEW_2020_0330_good.pdf

Both are comfortably larger than the 39 inch diameter for the Bryant drive. And as both platters are still around, someone should be able to make a precise measurement for the record books.

 

Best wishes,


Tom

 

 

 

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-- 

Salem Elzway
PhD Candidate
Department of History
University of Michigan
(402)730-4775
salem.elzway at gmail.com

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