Re: 'Frankenstein' Disk Drives, Done Cheap

Have you seen "Safe VSP" demo?
http://csdb.dk/release/?id=115690

Has explanation in the top scroller:
http://csdb.dk/release/text.php?id=853


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On Thu, 24/4/14, smf <smf@null.net> wrote:

 Subject: Re: 'Frankenstein' Disk Drives, Done Cheap
 To: cbm-hackers@musoftware.de
 Received: Thursday, 24 April, 2014, 8:39 PM
 
 Re: 'Frankenstein' Disk Drives, Done Cheap
  
 
 >3: there is provision for a workaround for silent memory corruptions caused by memory refresh glitches,
 > when fooling around with the VIC chip timing (a technique called VSP).  Having witnessed the problem
 > first hand (and "fixed" it by  retrofitting NOS RAM in my own machine)  - I'd like to know how this
 > has been achieved.
  
 VSP corrupts memory because VIC changes it’s mind part way through a cycle 
 at what it’s reading. DRAM can’t cope with that and it causes data to flow from 
 one place to another. I guess that this chip detects VIC partying on the bus and 
 does something to stop it from changing the bus at that crucial time.
  
 For the exact how you’ll need to ask them.
  
 

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