[Cryptography] Secure erasure

Bill Frantz frantz at pwpconsult.com
Wed Sep 21 01:52:10 EDT 2016


On 9/11/16 at 4:23 AM, leichter at lrw.com (Jerry Leichter) wrote:

>The IBM 360 was the first, by a good long margin, though 
>actually I'm not sure when IBM first published its standard.

When the 360 came out, IBM was a fairly open company. The source 
for the OS was available. The System 360 Principles of Operation 
(PofO) was probably released in much the same maner as the 
similar document for the DEC VAX, with history and 
implementation suggestions eliminated from the public version. 
(I don't know this for a fact, but it seems reasonable.)

The real genius in the PofO was the way it was produced. The 
story goes that when some implementator asked, "How is 
<something> supposed to work?", the question was not answered. 
Instead, the relevant section of the PofO was rewritten and the 
questioner asked, "Now do you understand?" The result was a very 
precise and understandable manual about a very complex system.

10-15 years later, IBM started drifting down the secrecy path. :-(

Cheers - Bill

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