A. Call to EN^DIB

Both versions of FileMan support this (rarely used) entry point, which allows the user to edit a self-selected list of fields for a given File. However, DHCP FileMan uses the input variable 'DIE' to specify which File to edit, whereas CHCS FileMan uses the variable 'DIC'.

Portability effect: Requires conversion. DHCP calls to this enty point would need to switch 'DIE' to 'DIC' to run under CHCS. Vice versa, CHCS calls to 'EN^DIB' would need to call the input variable 'DIE', rather than 'DIC'. Ouch!

B. Calls to the ^DIC routine

One of the most vexing discrepancies between the two systems has already documented, in Section VI above, as a "User-Interaction Incompatibility". This is the issue of lookup "not stopping at an exact match".

Portability Effect: Requires conversion. This issue is even more serious as a programming concern than as a user-interaction concern, because of the unexpected behavior that could be exhibited by programs that call ^DIC in CHCS. Suppose that a CHCS program calls ^DIC with an input value of 'X' defined, and with "E" (but not "A") in the 'DIC(0)' parameter string. Let us say that the program 'knows' that 'X' is the precise, unique name of one of the Entries in the File in question.

This CHCS program expects the ^DIC routine to simply 'echo' any Identifiers for the Entry named by 'X', and then QUIT with the output variable 'Y' defined, as always. For example,


If this code were to be ported to DHCP, and if, to use the earlier example, "SUSAN" and "SUSANNA" were both Entry names to be found in File 4444, then the ^DIC routine would do a READ from the current device, after presenting



Choose 1 or 2:

This READ would be behavior unexpected by the original programmer. One can imagine other scenarios that would run afoul of DHCP's ^DIC behavior, and the worst thing about these discrepancies is that they would be so hard to detect in advance: calls to ^DIC are found in Globals, as well as in almost every CHCS MUMPS Routine.

A general, if onerous, workaround rule would be as follows: All ^DIC calls which supply ^DIC with an 'X' value, and which include "E" in the 'DIC(0)' parameter string, should be modified so that "O" is also included in 'DIC(0)'. (Fortunately, "O" in 'DIC(0)' has no effect in a call to ^DIC in CHCS FileMan, so this workaround could be made on code even while it still operates with CHCS.)

DHCP FileMan supports a documented call to the entry point "FILE^DICN", which has the result of "filing" an Entry or sub-Entry. Unfortunately, although a tag named "FILE" can also be found in the 'DICN' routine that is part of CHCS FileMan, the behavior of the code found there is not identical to that of the VA subroutine of the same name.

Portability Effect: Requires conversion. VA documentation states that the MUMPS variable 'DO' must be killed before calling FILE^DICN. In CHCS, contrariwise, 'DO' must be defined at entry to FILE^DICN. Hence, at minimum, every DHCP call to FILE^DICN would need to be modified to include something like


before the call. It should be noted, too, that the logic used by CHCS FileMan to 'LOCK' and 'UNLOCK' the File being updated is quite different in the two systems.

C. Calls to the ^DIE routine

In DHCP FileMan, the subscripted variable DIE("NO^") is allowed to have two values which are meaningless in CHCS FileMan. These values are "BACK" and "BACKOUTOK".

Portability Effect: Minor. When ported to CHCS, this "BACK" feature would become inoperative. However, we can assume, hopefully, that it is an "ease-of-use" feature in most cases. One could perversely imagine a DHCP Input Template that at somepoint instructed the user


which in CHCS FileMan would, shall we say, lead to user frustration.

D. Calls to the ^DIK routine

DHCP FileMan supports two re-indexing calls to ^DIK under which only certain cross-references are re-done. These Entry points, 'ENALL' and 'EN', do not exist in CHCS FileMan, and no similar functionality is supported there.

Portability effect: SERIOUS Any calls to 'ENALL^DIK' or 'EN^DIK' in DHCP code ported to a CHCS environment would be unworkable there. If such functionality were required in a CHCS environment, the best course would probably be to re-do the DHCP code somewhere other than in the ^DIK routine.

E. Calls to the ^DIP Routine

In DHCP FileMan, 'DIOBEG' is the name of one of the optional input variables to the 'DIP' output routine. This variable is a string of MUMPS code which is executed before the printout begins. CHCS FileMan has an equivalent input variable, named 'DIOBEGIN'. The 'DIOBEGIN' code is also "executed before the printout begins". However, in CHCS FileMan, an initial form-feed is sent to a printer output device after the 'DIOBEGIN' code is executed. This may result in output that looks different in the two systems.

Portability Effect: Requires Conversion. Any DHCP code which calls ^DIP needs to be examined. If the optional 'DIOBEG' variable is set, it must be re-named 'DIOBEGIN' in code ported to CHCS, and the form-feed discrepancy mentioned above must be considered.

'DIASKHD' is the name of another optional input variable to DHCP FileMan's 'DIP' routine. If present, it forces the user to type in the Header of the report at run time. As mentioned above, CHCS FileMan has no equivalent variable.

Portability effect: Requires conversion. DHCP code which used the 'DIASKHD' variable in calling '^DIP' would not work as designed if ported to a CHCS environment. The workaround would be to add this code before the call:


With this change, the only difference in behavior between the two systems would be that, in the new CHCS environment, the user would answer the HEADER: question without seeing a default prompt.

DHCP FileMan (in conjunction with the VA Kernel's Task Manager module) allows the programmer to use the variables 'DISTOP' and 'DISTOP("C")' to help control output that is queued in the course of a call to ^DIP. CHCS FileMan offers no equivalent functionality.

Portability effect: Uncertain. DHCP programmers who have availed themselves of this kind of control over queued output are probably designing a special-purpose application that will never be ported. Nevertheless, code transported to CHCS should be examined for the occurrence of these 'DISTOP' variables, since they would be ignored under CHCS FileMan and Kernel.

F. Calls to the ^DIQ Routine

In DHCP FileMan, an optional input variable, 'DIQ(0)', can be used in the call


to tell the DIQ routine to display either computed fields, or audit records, for the selected Entry. Contrary to some CHCS documentation ("MISO 108"), this functionality is not available in the corresponding EN^DIQ call in CHCS FileMan.

Portability Effect: Uncertain. Clearly, a DHCP routine containing a 'DIQ(0)' parameter in its EN^DIQ call would, if ported to CHCS, generate less information for the end user in that environment. It is unlikely, however, that crucial information would be displayed in this way. A workaround to the problem might be to create a Print Template to display the computed or audit data required. Note that any CHCS FileMan File can be printed using two special Print Templates not present in DHCP: the "CHANGES CAPTIONED" Template, and the "HISTORICAL CAPTIONED OUTPUT" Template. These Templates show audit-trail information on any Field that has been changed. Note, too, that CHCS FileMan has a Computed-Field Function called "PRIOR", which can be used to display previous values of data in Files that have been audited. This Function is multiple-valued; specifying a "PRINT FIELD" that looks like


might generate a vector of values like





if a particular NAME Field's value had changed four times since auditing of the File had begun.

G. Listing and Deleting Files

CHCS FileMan has no entry point, such as "EN^DIU2" in DHCP FileMan, whereby a programmer can delete a File and/or its Data Dictionary. Presumably, calls to this DHCP utility are quite rare!

Portability effect: Requires conversion. Fortunately, a DHCP call to EN^DIU2 is essentially a call to ^DIU0, and there is no "DIU0" routine in CHCS FileMan. Therefore, the simplest way to retain the "EN^DIU2" functionality within CHCS (should that be desired) is simply to move the DHCP version of ^DIU0 into CHCS, and change what few calls there may be from "EN^DIU2" to "^DIU0".

CHCS FileMan also does not have an Entry Point like "EN^DID" (documented in Version 21 of DHCP FileMan) to output a Data Dictionary listing.

Portability effect: Requires conversion. If emulation of this (new) Entry point were required within CHCS, its name would need to be changed, and some re-interfacing done with the CHCS "DID" routine.

H. Calls to Routines Non-existent in CHCS

Finally, we itemize a number of Entry Points, routines, and namespaces that are callable as DHCP FileMan utilities, but which do not exist in any comparable version in CHCS. ^DIAC and the ^DIR* routines could easily be moved into the CHCS FileMan suite, as suggested below. Calls to the other utilities listed below, however, must be considered non-portable to CHCS.

DDBR* Namespace

The "Browser" utilities of Version 21 are unavailable in CHCS.


This simple "File Access Determination" routine could easily be inserted into the CHCS FileMan suite, but it does not exist there now. (Note: "DIAC^DIC" does something rather different in CHCS.)


The Version 21 Database Server does not exist in CHCS FileMan.


The "Data Extractor" is not available in CHCS.

DDS* Namespace

As we hope was made clear in Section VII., none of the DHCP ScreenMan calls will work in the CHCS environment.

DIFG* Namespace

'FileGrams' are electronic-mail messages which capture data from FileMan databases, and can be read by software, to transfer such data from one FileMan system to another. They will be discussed below, in the next Section. DHCP FileMan provides programmers two MUMPS Entry points, EN^DIFGG and ^DIFG, which can be used to generate and install FileGrams. Although CHCS FileMan supports the concept of a FileGram in a rudimentary way, no programmer calls equivalent to the entry points EN^DIFGG or ^DIFG exist within CHCS FileMan.


Although CHCS FileMan actually includes a kind of "Cross-Reference Compilation", derived from the VA work, and a DIKZ routine, this DHCP Entry point has no CHCS equivalent.

^DILF* Namespace

CHCS FileMan has no Library functions such as ""$$ROUSIZE^DILF". The CHCS Kernel includes some special "%"-routines that might include equivalent fuctionality.

DIR* namespace

CHCS FileMan has no "reader" utility analogous to the ^DIR routines in DHCP FileMan. Actually, CHCS FileMan includes some routines in the "DIR*" routine namespace for another purpose, that of archiving (see next Section), but these are pretty much unused. Any effort to port DHCP software to a CHCS environment should surely include transferring the DHCP ^DIR logic into CHCS FileMan, since "^DIR" is widely used in DHCP. The easiest way to do this would simply be to write over the CHCS routines. If the archiving functionality of those CHCS routines is to be retained, it would be easier to rework their namespace, rather than transferring the DHCP DIR* routines to some other namespace, and changing all programmer calls from "^DIR" to that new routine name.