Is it renaming the file, or leaving the original file untouched and creating a new file?

Hi
Thanks for your interest.
My system is writing a new file with the extension .dat but somehow windows changes it to 0X or 1X. Under WIN98 this would happen when I ran about half of my programs including , rename, copy and definition editors. With XP it only a few progs that it happens. My system thinks memory is 64K. To sort a larger file it writes it into 32K temporary files called stmp1.$$$ stemp2.$$$ etc until original file is all read. Then it will merge these files together to write out the sorted file. My system says 'Cannot open stemp1.$$$'. When I look at the file Its called stemp1.0X.
Any help would be greatly appreciated.

With DOS, writing to the same filename caused automatic replacement. With Windows 95 and later, such an action will create a new file. You have to explicitely delete the old file before opening the replacement file to prevent renaming.

When I use my sort program stemp files dont exist at the start. They are deleted each time sort is finished. I just tried it again under WIN98 There are 5 files named stemp1 through 5 - all with ext of 1X. so when the merge starts it cant find stemp1.$$$

Are you trying to use a DOS application in windows?

Yes. Its a datebase program called FMS80, written in 1980. It consists of a suite of 35 programs for making file definitions, control definitions, reports etc. FMS has its own language and (with very little skill and limited programing knowledge) I have written cash register, stock control, P&L and balance sheets - about 200 progs over the last 20 years. Its great working in dos. My computer boots in about 10 seconds, never crashes no blue screens or strange error messages - But I can see Mr Gates is backing me into a corner and I must try to get into the 21st century. I have FMS on a FAT16 C drive with WIN98 but boot to XP on E drive. I use autoxec.nt and config.nt the same as I did with WIN98 dos.
Every thing works just fine exept for this.
Regards
Acer1

The problem is that the .$$$ extension was always an illegal extension name, but DOS allowed it.

Using my file definition editor under WIN98 would create a file AFILE.0X instead of AFILE.FD Undex XP the created file is AFILE.FD as it should be. Is .fd allowed under XP? Does XP keep a list of extensions somewhere?

The list of extension associations is found in My Computer or Windows Explorer. Use:

tools / folder options / file types

You can then browse which extensions are in use on your computer, and what program they are associated with. You can also create a new association (but you must know where your program is stored to do this).

This will tell the computer which application to open a file with. It won't tell the application where the file is or what its extension is.

You can create a shortcut for the application which can tell it which folder the files are in.