🚀 go-pugleaf

In article <826787631snz@bitmap-brothers.co.uk>
           SteveC@bitmap-brothers.co.uk "Steve Cargill" writes:

> In article <826745441snz@longley.demon.co.uk>
>            David@longley.demon.co.uk "David Longley" writes:
> 
> [SNIP]
> > Unzipping files produces CRC errors on a number of the contents. The file
> > checks out OK on other systems, and the problem disappears when I disable
> > both EXTERNAL CACHE and TURBO CACHE in the BIOS.
> [SNIP]
> > Anyone got an explantion for certain? (my own conjectures are easily read
> > from the above!).
> 
> David, I think I've got just the answer :-
> 
> ++QUOTE++
> 
> During the development of PKZIP v. 2.0 for MS-DOS, PKWARE has 
> discovered hardware faults in newer 80386 & 80486 computers. 
> These faults can cause anomalies in the operation of PKWARE 
> software as well as other software.
> 
> PKWARE has been endeavoring to locate an anomaly that has been 
> observed by a number of customers and associated vendors.  The 
> intial symptoms of the problem were:
>         
>   - Particular files extracting with errors on one machine, but not
>     on another.  
>        
>   - Installs of some products failing.
> 
> These problems have been observed primarily on newer, fast (33Mhz 
> or faster) 80386 and 80486 machines.  Investigation of the problem 
> revealed no difference in software or hardware between machines 
> that failed and machines which did not.  The files which fail do 
> not fail every time.
> 
> To further test where the problem was occuring, a very simple 
> program which would load a test file into a RAM buffer and then 
> copy it to a second RAM buffer was created.  The program then 
> compares the two buffers one byte at a time and reports any 
> discrepancies.  Discrepancies with even the simple copy were 
> noted.
> 
> If the EXTERNAL CACHE is turned off through the BIOS 
> configuration, the problem does not occur.
> 
> This is indeed a hardware flaw. 
> 
> While this effort to work around these hardware faults will, 
> unfortunately, delay the release of PKZIP v. 2.0 for MS-DOS, we 
> hope to release it in the next few months.
>  
> We know you will be pleased with the many new features and 
> enhancements to PKZIP.  We appreciate your understanding and 
> patience in our efforts to provide reliable software.
> 
> Sincerely,
> 
> PKWARE, Inc.
> 
> 
> 
> ++UNQUOTE++
> 
> I uploaded it to FTP.DEMON some time ago and it is in with the rest of
> the PC zip stuff.  What version of PKUNZIP are you using?  It should be
> 2.04g as I think your problem was solved by then.
> 
> ( I assume you don't want the controller cards anymore? )
> 
> Steve
> 
> -- 
> 
> Steve Cargill
> 
> ----------------------------------------------------------------------------
>     SteveC@bitmap-brothers.co.uk   |   http://www.bitmap-brothers.co.uk
> ----------------------------------------------------------------------------
> 
Great - this explains a lot - however - this was with pkzip 4.1v...

Well, you know me - I collect lots of old junk!  <g>

-- 
David Longley