strom%brl-bmd@sri-unix.UUCP (02/11/84)
From: Charlie Strom (NYU) <strom@brl-bmd> Another solution to the problem of multiple overlays is a program called SETDRU, authored by Mike Rubenstein. SETDRU is a BDOS filter which allows remapping of up to 8 file specifications (unambiguous or ambiguous) so that a program can access any other files on any drive/user. This works very well with Wordstar, and allows me to have a small (<1K) program called EDIT.COM on my ZCPR2 root du. Invoking EDIT will call Wordstar which could be on any other du as well as its overlays which could be on the same or yet another du. If ZCPR is not installed, one must have multiple copies of EDIT.COM, but not of WS or its overlays. SETDRU actually consists of a user interface and two filters, one that allows the filter to be bound to the .COM program of interest and another which calls the program. The latter is required for programs such as WS that test its integrity after re-entry from the R command. SETDRU is in Z80 code. I will be completing an 8080 conversion in a few days and will upload relevant files to Simtel at that time and will post a notice to the list. I have run this program successfully under CP/M Plus as well as 2.2.
CSTROM%simtel20@sri-unix.UUCP (03/16/84)
I have uploaded the following files to SIMTEL20, in the MICRO:<CPM.DIRUTL> directory: SETDRU.DOC SETDRU8080.COM SETDRUZ80.COM UNSETDRU.COM These files form the basis of a BDOS filter that can be used to direct search of files under CP/M 2.2 (and CP/M Plus). One of the most popular uses for this filter is to allow WordStar overlays to reside on any drive/user (either the same as WS.COM or another entirely) and to allow WordStar to be executed from any drive/user. The documentation is quite complete; the files were built from a combination of a C user interface and to M80 programs, which I will upload if demand merits. Note that the original program was a Z80-only affair; I converted it to 8080 code. UNSETDRU can de-install a redirection filter but is not necessary as long as the original file is properly backed-up before using SETDRU. -Charlie