旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� � DB/C Newsletter � � November 1993 � 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� Editor's Notes The ANSI Databus Standard is now in its second public review period. This review period will end December 28, 1993. The next X3J15 meeting is scheduled for January in Dallas. The first order of business for that meeting will be to forward the Standard through CBEMA to ANSI for final approval. This will probably take a couple of months. Then we will finally have an official ANSI Standard for DATABUS. The other topic of business at the X3J15 meeting will be the inclusion of an SQL interface in Standard DATABUS. Members of X3J15 will work with a liason from X3H2 (the SQL committee) in drafting a proposal for a standard SQL interface. We'll keep you informed about the progress of X3J15. This month's newsletter is a compendium of questions (and answers) that DB/C users have asked us. I hope you find it informative. DNW Questions --> What operating systems does DB/C 8.0 run on? (This question is frequently asked for various specific operating systems/environments.) The MS-DOS version of DB/C contains 3 different executables: the 8086 executable, the 80386 executable, and the Windows executable. The 8086 executable runs in MS-DOS, in the DOS window of Windows 3.1, and in Windows NT and OS/2 2.1. The 80386 executable only runs in MS-DOS on a 386 or higher; it does not run in other environments. The Windows version of DB/C runs under MS-Windows 3.1 (only in 386 mode), in Windows NT, and in OS/2 2.1. Each of the MS-DOS versions works in conjunction with Novell Netware, Microsoft Lan Manager, IBM Lan Server, Banyan and PowerLan. We have had a few inquiries about Windows NT, but interest seems to be minimal. The 8086 MS-DOS executable runs under it, but that's it for now. We plan to have full featured GUI and character mode versions for Windows NT sometime in 1994. Note that I said that the 8086 MS-DOS executable runs under Windows NT (and not just Windows NT on an Intel x86 or compatible chip) - Windows NT for the DEC ALPHA chip and for the MIPS chip includes a complete 8086 emulator, so the DOS executables will run under Windows NT on machines made with those chips. The OS/2 version of DB/C 8.0 (which is currently being beta tested) runs under the Presentation Manager on OS/2 2.1. There is also a version of DB/C 8.0 for OS/2 that runs on dumb terminals connected to OS/2 2.1. There is a DB/C 8.0 for the Macintosh on System 7. There are versions of DB/C for UNIX on the following machines: UNIX 386 SVR3.2 (iBCS2), UNIX 386 SVR4 (iABI), SCO XENIX 386, Amdahl UTS, AT&T 7000, BULL DPX2, DEC ALPHA ULTRIX, HP 90000, IBM RS/6000 AIX, Motorola 3000, MIPS 4000 SVR4, NCR 850, NCR 3000 SVR4, PYRAMID MISS/MIST, SEQUENT SYMMETRY PTX, Stratus XA/R, UNISYS 5000 and 6000 (not all models), and all computer systems based on the 88open standard. 88open machines include the Data General AViiON, the Motorola 8000, and many others. All UNIX versions of DB/C are for character mode only. They run fine under X-Windows, but there is not yet a GUI version of DB/C to run under X-Windows. There is a version of DB/C 8.0 for DEC VMS on VAX machines. There is another version of DB/C 8.0 for DEC VMS on ALPHA machines. DB/C does not run on MVS (IBM mainframes). DB/C does not run on the IBM AS/400. DB/C does not run on the HP 3000 with or without the POSIX emulator. DB/C 8.0 does not run under XENIX 286. DB/C 8.0 does not run on older versions of OS/2. DB/C does not run under OS/9. DB/C does not run on the Amiga. DB/C does not run on NeXTstep. --> Is DB/C now or ever going to be an Object Oriented Programming Language? (An OOPL). OOPLs have several defining features, but inheritance and data hiding are the most important. Other OO features include dynamic linking and polymorphism. DB/C does not have inheritance or polymorphism in the classic OOPL sense, but DB/C does have data hiding, dynamic linking and code modularity in the form of LOADMODs. See the March 1993 Newsletter for a discussion of the Extended Verbs that are included in DB/C 8.0. These Extended Verbs are a good example of objects in DB/C. They are dymamically linked objects that provide preprogrammed functionality. The concept of LOADMOD instances provides the foundation for using multiple objects of the same class at the same time. Therefore, the correct answer to the question is: DB/C has many object oriented features, but is probably not a real OOPL. However, C++ does not have dynamic linking, and it is considered to be an OOPL. SMALLTALK, a "pure" object oriented language, only has one level of inheritance (multiple inheritance isn't available). What about the future: Will DB/C ever be a real OOPL? The answer is: maybe. We have experimented with a design for inheritance, to be put into the next major release of DB/C. As of right now, it does not seem to be particulary useful to the programmer, and may not be included in the next release. As far as polymorphism is concerned, we believe that it is nothing more than a coding trick that is detrimental to program readability and maintenance. Therefore, we have no plans to include polymorphism in DB/C. If any readers are interested in this, talk to Don Wills at SWC. --> Why doesn't the Report Writer have the << ??? >> feature? We realize that the Report Writer needs several new features before it can become useful to you. Here is a list of some of the planned enhancements: Allow two or more files to be treated as one logical file. Allow ascending/descending order for a field in Order By. Allow left or centered justification of column headers. Add test mode, to stop after some number of records have been read. Add subtotals/totals only option. Allow text to be associated with subtotals/totals. Add ability to suppress a subtotal break within a break group. Allow run-time prompting for "Compare To Value" of Selection. Add CONTAINS and STARTS WITH options to Selection. Define an entry point to run the report writer from another program. --> Is the C Functions Reference Manual available yet for DB/C 8.0? Yes. The cost for software and 1 year of support is $750. --> The Internet has been discussed as a means of accessing the DB/C BBS. How do I get on the Internet? The Internet is a giant culture shock to the uninformed. I strongly urge you to read one or more books about it before you start exploring. The first three of the following books will contain information about how to find Internet access providers in your area. The fourth book is an interesting history of the Internet, and is also thought provoking about the future impact of digital communications on our society. The Whole Internet: User's Guide & Catalog by Ed Krol, published by O'Reilly & Associates The Internet Companion: A Beginner's Guide to Global Networking by Tracy LaQuey, published by Addison Wesley The Internet Complete Reference by Harley Hahn, publish by Osborne - McGraw Hill The Virtual Community: Homesteading on the Electronic Frontier by Howard Rheingold, published by Addison Wesley DB/C Class Schedule The next DB/C classes scheduled for January. The classes are held in the Oak Brook, Illinois office of Subject, Wills & Company. For more information, contact Judi Tamkevic at (708) 572-0240.