How the Visual FoxPro Setup Wizard Compresses Large Files

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When the Setup Wizard compresses files for assembly into disk images, it ensures that the files do not exceed the limit (in bytes) defined by the SplitSize value in the Preferences section of Wzsetup.ini. By default, this value is 363,520.

Files that fall below this limit are renamed with a $ in the filetype. For example, a 234,738-byte file named Mydata.dbf is compressed into:

   MYDATA.DB$    61,638
				

Files that exceed this limit are chopped into pieces. The pieces are given a generated filename and an extension that indicates the order in which they are re-assembled when installed on the target computer. For example, a 4,415,168-byte file named Mydata.fpt might be divided and compressed into:

   56600245.001   263,446
   56600245.002   344,833
   56600245.003   335,156
   56600245.004   323,052
   56600245.005   273,779
				

During installation on the target computer, these files are decompressed and reassembled into Mydata.fpt.

If you need to reassemble this table without running the setup program, you can use Expand.exe to expand each piece; then copy the expanded pieces of the memo file into the final memo file:

   EXPAND MYDATA.DB$ MYDATA.DBF
   EXPAND 56600245.001 MYDATA.001
   EXPAND 56600245.002 MYDATA.002
   EXPAND 56600245.003 MYDATA.003
   EXPAND 56600245.004 MYDATA.004
   EXPAND 56600245.005 MYDATA.005
   COPY MYDATA.001+MYDATA.002+MYDATA.003+MYDATA.004+MYDATA.005 MYDATA.FPT
				

To determine the original name of a compressed file, refer to the Application section of the Setup.inf file that is written to DISK1 (or NETSETUP) of the disk image directories:

[Application]
"56592553"=1,MYDATA.DB$,,,,,,,,!READONLY,,MYDATA.DBF,,,,234738,,,,,VITAL
"56592734"=1,56600245.001,,,,,,,,!READONLY,,MYDATA.FPT,,,,727040,,,,,VITAL
"56592734"=1,56600245.002,MYDATA.FPT,,,,,,,!READONLY,,,,,,952832,,,,,VITAL
"56592734"=1,56600245.003,MYDATA.FPT,,,,,,,!READONLY,,,,,,953856,,,,,VITAL
"56592734"=1,56600245.004,MYDATA.FPT,,,,,,,!READONLY,,,,,,982528,,,,,VITAL
"56592734"=1,56600245.005,MYDATA.FPT,,,,,,,!READONLY,,,,,,798912,,,,,VITAL
				

The default SplitSize value of 363,520 is held over from the FoxPro version 2.6 Setup Wizard, which was able to generate 360K disk images and needed to ensure that files would not exceed the capacity of a 360K disk. While the version 3.0 Setup Wizard does not generate 360K disk images, the SplitSize value of 353,520 provides improved flexibility when assembling files into 1.2-MB and 1.44-MB disk images.

The version 3.0 Setup Wizard is able to split a file into hundreds of pieces by using a numeric file extension. The file extension may extend from 001 to 999, but a directory limitation (or setup limitation) may be encountered before getting that far.

The SplitSize setting may be increased to cause the Setup Wizard to create larger chunks when it splits large files. Do this by modifying the SplitSize setting in Wzsetup.ini. Do not use a setting greater than the number of bytes that will fit on 1.2-MB disks (or 1.44-MB disks). Some experimentation and testing may be required to arrive at settings that work well for the specific application.