DiskSort.doc      rev 1.00   17/6/98   (c) ISS Ltd   jerry@iss.u-net.com

DiskSort.DLL      Delphi16 - sort large files

DSortDll.EXE      Testbed for DiskSort.DLL   VB4 16 bit
DSortDll.VBP      Source for DSortDll.EXE
DSortDll.FRM        ..
Support .BAS        ..

DSortPas.DPR      Delphi16 sample for invoking DiskSort.DLL

FREEWARE may be distributed without licence provided 
DiskSort.DLL is not modified.

Timings:  P200                speed mainly determined by disk access
          
          250kb   1 sec
          500kb   2 secs
          1mb     6 secs
          2mb    15 secs
          3mb    24 secs
          10mb  112 secs

Method:
          Recursive Binary division of file into two buffers
          sort at lowest level and work back up merging two buffers
          at a time.
          Principle - to minimize disk head seeking.
                      to minimize memory usage - always 180kb Work Ram.
                      to standardize sort time regardless of Ram.

          Uses DISKSORT.TMP in same directory as file to be sorted
          as a temporary file. DISKSORT.TMP is deleted on exit.

Note:     While two+ instances of DiskSort.DLL may run at the same time
          they will collide if working in the same directory as
          DISKSORT.TMP will be in use by the earlier instance.

          Jumpy progress line under W95 is due to file buffering
          (ie: sometimes a read does not actually go to disk)




