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<P DIR=LTR><SPAN LANG="en-gb"><FONT FACE="Calibri">I have attached the source files for the difference di</FONT></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">sk functionality I mentioned. I have compiled it on 32 and 64 bit Windows and on 32-bit Linux (an oldish Slackware distribution).</FONT></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri"> I have only tested it for VAX 780.</FONT></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri"> I have no</FONT></SPAN><SPAN LANG="en-gb"> <FONT FACE="Calibri">easy way to test on 64-bit Linux and do not have a MAC or knowledge how to use a MAC. Therefore if someone would be prepared to test the code on those platforms that would be great. The sources are based on SIMH</FONT></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri"> 3.8-1. Here are the commands:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><B></B></SPAN><B><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">DIFF ATTACH <Unit> <DifferenceFile> <BlockSize></FONT></SPAN></B></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">Attaches a difference disk file to a unit. The unit must already be attached and be a random access virtual disk. The <DifferenceFile> is the name of the file to attach that contains the differences. If the file does not exist a new one is created. The <BlockSize> is only used when the difference disk file is created. The unit's virtual disk is divided into blocks of this size and differences are recorded at this block level. The <BlockSize> parameter is ignored if the difference file already exists.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><B></B></SPAN><B><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">DIFF DETACH <Unit></FONT></SPAN></B></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">Detaches the difference file from the unit. Normal operation without differencing is resumed. However it is not advisable to continue running the simulated machine after doing this as it is likely to invalidate the difference disk. There is no mechanism to tell that the underlying disk has been changed since the difference disk was last used.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><B></B></SPAN><B><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">DIFF MERGE <Unit></FONT></SPAN></B></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">Merges the attached difference disk back for the <Unit> into the original disk and then deletes the difference disk file. Requires the difference disk to have already been attached.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><B></B></SPAN><B><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">DIFF COMPAR</FONT><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">E <Unit> <VirtualDiskFile> <DifferenceFile> <BlockSize></FONT></SPAN></B></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">Compares the virtual disk file attached to the <Unit> against another <VirtualDiskFile> and creates a new <DifferenceFile> with the given <BlockSize>. If the unit has a difference disk attached the differences in that difference disk are ignored, the base virtual disk is used.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><B></B></SPAN><B><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT COLOR="#4F81BD" SIZE=4 FACE="Cambria">DIFF STATS</FONT></SPAN></B></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Calibri">Prints some statistics about the difference disk files.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT FACE="Arial" SIZE=2 COLOR="#000000"> <<...>> </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT FACE="Calibri">Regards</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT FACE="Calibri">Robert Jarratt</FONT></SPAN><SPAN LANG="en-gb"></SPAN></P>
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