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Vancouver Area Rainbow Users Group N e w s l e t t e r January and February, 1991; Volume 5, Number 1 Editor: David P. Maroun, 9395 Windsor Street, Chilliwack, BC, Canada V2P 6C5; telephone (604) 792-4071 Publisher: DECUS Canada, 505 University Avenue, 15th Floor, Toronto, Ontario, Canada M5G 1X4; telephone (416) 597-3437 ----------------------------------------------------------------------------------- This newsletter is provided free of charge to members of the Vancouver personal computer local users group (Vancouver PC LUG) also called the Vancouver Area Rainbow Users Group (VARUG). The group forms part of the Digital Equipment Computer Users Society (DECUS) of Canada. Membership in the local users group is free for anyone using a personal computer made by Digital Equipment Corporation or used with Digital products. Members need not live near Vancouver. Unless the contrary is indicated, any part of this newsletter may be freely copied or distributed unaltered and with credit given to the original source. While the information provided is believed accurate, the editor cannot take responsibility for contributions of other writers. ----------------------------------------------------------------------------------- Deadlines: For our March and April issue: February 28, 1991 For our May and June issue: April 30, 1991 Almost any legible format is acceptable for submissions, but the ideal is ASCII form on diskette. Diskettes should be accompanied by covering letters describing the files and indicating disk format. We prefer Rainbow CP/M or Rainbow MS-DOS but can handle most other CP/M and MS-DOS formats too (check about them). ----------------------------------------------------------------------------------- Table Of Contents Editorial: The Status Of Our Group ................... David P. Maroun ..... Wanted: A Representative At The Next Leadership Conference ....................... David P. Maroun ..... A WordPerfect Bulletin Board ................................................ Follow-Up: Sources Of Components ........................................... Nominations To The DECUS Board Of Directors ........... Marcus E. Schack .... In The News ................................................................. Recent Additions To The Group Library ....................................... Review: SupraModem 2400 External Modem ............... Wilson C.Y. Chang ... An Introduction To The C Programming Language ......... Jeffrey S. Katz ..... Video Boards ................................................................ Questions And Answers ....................................................... Buy, Sell, Or Swap .......................................................... ----------------------------------------------------------------------------------- Editorial: The Status Of Our Group by David P. Maroun While I was at the 1990 leadership conference, I received a plaque certifying that the Vancouver PC local users group was accredited as a part of the Digital Equipment Computer Users Society, Canada Chapter (DECUS Canada) on May 3, 1985. For the time being, the plaque stands on a shelf in my living room. I am open to suggestions for a better place to put the plaque. One project I have scheduled for 1991 is a greater collaboration between our group and Digital Equipment Corporation. I am pleased to note that Digital has cooperated by naming Doug Moore of the Richmond, BC, office as the company's delegate to our group. I met Doug before, and got from him literature which formed the basis for articles in this newsletter. I look forward to working further with him. Other group activities continue. Members contact each other on an individual basis. The newsletter begins its fifth year of publication. And the software library continues to grow. Our group has focussed especially on the Rainbow computer. That focus will continue. However, we welcome those working on other personal computers in Digital contexts, and I hope to have more articles on those machines. Long-time readers of this newsletter may remember that I have not only a Rainbow but also a Tandy Color Computer. So I represent both users of Rainbows and users of non-Rainbows. I would like to hear more from people in that second group. ----------------------------------------------------------------------------------- Wanted: A Representative At The Next Leadership Conference By David P. Maroun So far, DECUS Canada has held three leadership conferences, and I have attended each one. While I enjoyed and benefited from them, I think that other people in our group should participate. The next leadership conference is scheduled for Halifax, Nova Scotia, in the Fall of 1991. DECUS arranges the details, and pays basic travel, lodging, and food expenses of all those attending. Does anyone in the Vancouver PC local users group want an expenses-paid trip to Halifax, the opportunity to learn more about DECUS, and perhaps help guide DECUS Canada in its future development? If so, please contact me. ----------------------------------------------------------------------------------- A WordPerfect Bulletin Board Do you need another printer driver for your copy of WordPerfect? You may be able to get it from WordPerfect Corporation's bulletin board. To gain access to the board, have your computer ready with communications software and a modem, and telephone (801) 225-4414. The board is available free of charge, but you need a valid WordPerfect serial number. ----------------------------------------------------------------------------------- Follow-Up: Sources Of Components The last issue of the VARUG newsletter carried an article on repairing LA50 printers which mentioned DC to DC converters. The article mentioned two models. One member of our group has found another: Model A12C10AC from Computer Components Source Incorporated 135 Eileen Way Syosset, New York 11791 United States Of America Telephone (516) 496-8727 Another supplier of electronic components is: CRC Components Canada Incorporated 951 Denison Street, #17 Markham, Ontario Canada L3R 3W9 Telephone (416) 513-6422 ----------------------------------------------------------------------------------- Nominations To The DECUS Board Of Directors Submitted by Marcus E. Schack Chairman DECUS Canada Nominating Committee Memorandum from the Nominating Committee: The DECUS Canada Nominating Committee is pleased to announce the three candidates we believe can make an excellent contribution to the Board should they be elected. This year was a particularly tough time in choosing ONLY three people from the initial seven volunteers. We extend our sincere thanks to all the candidates for their commitment to DECUS Canada. The Nominating committee recommends that the following DECUS members be considered for the three available positions on the DECUS Canada Board of Director, commencing July 1, 1991. Alan Clifford - Calgary, Alberta We know him best as DECUScope editor and playing a key role in producing this publication quarterly. He is looking to bring his private business expertise to DECUS in vying for the Vice-President of Finance position. Ruben Boiardi - Montreal, Quebec Reuben's vision of the future and the energy level to follow through make him a strong candidate for the board. He also comes from a 'hot spot' of renewed DECUS activity, the province of Quebec. Grace Brauen - Ottawa, Ontario Grace is currently serving in the capacity of Ottawa Symposium Co-Chair and has shown herself to be a dynamic figure capable of carrying out any tasks given her. Her boundless energy and enthusiasm will be tested should she be elected to the Board. The Election Process: We invite DECUS members to consider contributing to the national organization through the DECUS Executive Board. Nominations for election to the Board from the general membership must be made in writing to the Nominating Committee before March 3, 1991. Nominations must include the signatures of not less than 50 DECUS Canada members and the signature of the nominee, indicating willingness to act if elected. Nomination forms are available from the DECUS Office. If no other nominations are received from the general membership, then the three candidates selected by the Nominating Committee will be appointed to the Executive Board of Directors. If the Nominating Committee does receive nominations from the membership, an election will be held (election will close June 3, 1991). Please send your nominations to the DECUS Office, ATTENTION: NOMINATING COMMITTEE. ----------------------------------------------------------------------------------- In The News An Alliance Against Software Piracy ----------------------------------- Microsoft Canada Incorporated, Lotus Development Canada Limited, Ashton-Tate Canada, Novell Canada Limited, and Quarterdeck Office Systems Canada Incorporated have formed the Canadian Alliance Against Software Theft (CAAST). The purpose of the CAAST is to prevent unauthorized use of proprietary software. The members of the CAAST have indicated that they will give special attention to corporations and organizations in the public sector. dBASE III Plus Copyright Rendered Invalid ----------------------------------------- As a result of a judgment rendered by United States judge Terrence Hatter in December, Ashton-Tate has lost copyright protection on dBASE III Plus. Judge Hatter based his decision on Ashton-Tate's failure, when the company obtained the copyright, to disclose that dBASE III Plus was based on JPL/DIS. JPL/DIS was developed at the Jet Propulsion Laboratories in Pasadena, California. The judge's decision was taken as a victory for Ashton-Tate's competitors, such as Fox Software, who use the dBASE language. DEC Canada Collaborates With Alberta's ATRC ------------------------------------------- Digital Equipment Of Canada Limited (DEC) has signed a five-year agreement with the Alberta Telecommunications Research Center (ATRC) in Edmonton. The agreement gives DEC access to research, especially on fiber optics and optical communications, while ATRC will get one million dollars as cash, equipment, scholarships for graduate students, and consultancy services. Enhanced Access To MS-DOS Files On A Macintosh ---------------------------------------------- Dayna Communications has announced version 2.0 of its DOS Mounter, which allows users of an Apple Macintosh computer to have access to MS-DOS files directly from the Finder. The company claims that version 2.0 is faster, can format MS-DOS diskettes, and permits launching a Mac program by double-clicking on an MS-DOS icon just as if it were a Macintosh icon. Further information is available from David Pascoe of Dayna, telephone (801) 531-0600. Lotus Buys Samna ---------------- Lotus Development Corporation of Cambridge, Massachusetts, has announced that it is buying Samna Corporation of Atlanta. The purchase allows Lotus to add graphical word processors, Samna Ami and Samna Ami Professional, to its product line. The Vancouver Public Library Allows Computer Access --------------------------------------------------- With the aid of a computer and a modem, individuals can now dial into the Vancouver, British Columbia, public library's on-line catalog. Users can dial (604) 665-5010 at 300, 1200, or 2400 bits per second. Available terminal emulations include ANSI, VT52, VT100, Wyse, and ADDS Regent. Vestronix Acts On Internal Problems ----------------------------------- Waterloo, Ontario's Vestronix Incorporated, suppliers of the Pro-C development tool for C-language programmers (described in a previous issue of the VARUG newsletter), has laid off 50 employees, written off two million dollars in bad accounts, and reworked a business plan. The company has also forced the resignation of president Grant Gee, and has hired Peat Marwick Thorne Limited to audit third quarter results. Tim Twinam of Vestronix has indicated that the company's difficulties do not affect Pro-C. ----------------------------------------------------------------------------------- Recent Additions To The Group Library The following files have been added to the Vancouver PC local users group software library. All the files are either in the public domain or are shareware. Shareware is supplied free of charge, but regular users of a shareware program are expected to pay a fee directly to the author. The programs are supplied as is. Many, but not all, were tested by members of the group. Some of the programs require specific hardware or support software. Documentation included with the programs can usually help decide what is needed. Comments based on actual trials follow the list of files. You should read those comments with caution; you may be able to run a program even though someone else had difficulty, and you may have difficulty while another person had none. Note that in some cases, we report that a program ran under Code Blue 2.01 and MS-DOS 3.10b on a Rainbow. In those cases, the copy of Code Blue used had been modified to take full advantage of MS-DOS 3.10b. The modification was done by using files supplied with MS-DOS 3.10b. To get copies of these files, contact the librarian: Ken Alger 6001 Pine Park Place Nanaimo, BC Canada V9T 3B6 Telephone (604) 390-4482 ---------------------------------- CP/M Files ---------- TTYPE LBR Typing tutor for DEC Rainbows VDE266 LBR Word processor MS-DOS Files ------------ ARCA129 LZH Creates or adds to .ARC files. The archive includes 8088 and 80286 versions of the program. ARCE40F LZH Extracts from .ARC files. ARCF106 LZH Finds strings in .ARC files. ARCV121 LZH Views directories of .ARC files. ASEZAS40 LZH As Easy As spreadsheet for IBM PC compatibles, version 4.0 ASMGEN22 ZIP Disassembler BUERGDOC LZH Documentation on Vernon Buerg's utilities CG LZH Breaks up files and puts them together again. CHK4LZ LZH Checks for compression by LZEXE. On Rainbows, needs MS-DOS 3.10b. CKOT11 LZH Checks archived files for viruses. CLEANP63 LZH Cleans up virus-infected programs; version 6.3. CLEANP67 LZH Removes viruses from files. D86V32 ZIP Assembler and symbolic debugger; compatible with IBM PCs, DEC Rainbows, and other computers. DECWPRIN ZIP WordPerfect 4.1 & 4.2 drivers for DEC printers DELDUP23 LZH Deletes duplicate files in different directories. DESIGNER LZH BASIC routines for animation DIAGS ZIP Diagnostics program DIS300 ZIP MS-DOS directory management shell DISKCACH ARC Untested disk caching system DOG206 ZIP Disk Organizer version 2.06 file de-fragmenter DRLIST-J LZH ANSI version of the LIST text viewing utility; suitable for Rainbows. DTC2 LZH Desk top calendar, with FORTRAN source code and extra utilities, including an RX50 driver for IBM ATs ENVIRON ZIP Controls the MS-DOS environment for a DEC Rainbow. FBR176 LZH Backs up and restores files. FSPOOL ZIP Re-directs MS-DOS printer output to a file. FV127 LZH Views the directories of various archives or libraries. FV131 LZH Views the directories of .ARC, .DWC, .LBR, .LZH, .PAK, .ZIP, and .ZOO archives. GS13DOC ZIP GhostScript 1.3 Documentation ... View Postscript on the screen. GS13EXE ZIP GhostScript 1.3 EGA/80286 executable GS13SRC ZIP GhostScript 1.3 "C" source code HDDIAG ZIP Hard disk diagnostics program, V2.10 (low level format and so on) HELPSB ZIP MS-DOS help program, similar to VMS help for users ISLZEXE ZIP Checks whether an .EXE files was compressed by LZEXE. JETSET ZIP Flight simulator for Rainbows LDIR41 LZH Lists directories in various orders. LIST72A ZIP View text files quickly on the screen. LIST73D LZH Buerg's versatile file viewing utilities; version 7.3D LIST74A LZH Versatile text viewing utilities; on a Rainbow, require Code Blue with '/V' and possibly '/C'. LISTLOGI LZH Mouse driver for LIST LJ2UP2 ZIP Prints 2 pages per page sideways on a Hewlett-Packard LaserJet (needs an 80286 or V20 chip). LJBOOK27 LZH Puts text into book form for Hewlett-Packard LaserJets. LP-HP18 LZH Formats & prints text on LaserJet printers LZEXE91 ZIP Reduces the sizes of .EXE files. MESSAGES ARC Telephone message database MICRO LZH Produces small print from Rainbows on DEC printers. MLRB ARC Rainbow mailing list program; with source code MMDRIVE ARC How to create two or more RAM drives MODEMD22 ZIP Modem Doctor 2.2 serial port and Hayes-compatible modem tester. MSTRKY17 ZIP Various disk and file utilities OCT90 ZIP d:BUG newsletter for October, 1990 PAK251 LZH PAK archiver version 2.51 PCFDOC ARC Documentation for PC-FILE + version 1.0 PCFILE-1 ARC PC-FILE + 1.0; on a Rainbow, use with Code Blue and its '/V' option PCFILE-2 ARC Extra utilities and a sample database for PC-FILE + 1.0 PCFILE-3 ARC Sample database, documentation, and utilities for PC-FILE + 1.0. PCZ21189 ZIP PC Zmodem, supplies Zmodem abilities to communications programs PKZ102-2 EXE PKZIP archiver version 1.02, OS/2 and MS-DOS executables QDR33D LZH Quick formatter for floppy disks. Not for RX50 drives. RAIND111 LZH Allows using Rainbow MS-DOS diskettes in 80-track, 5.25-inch drives on non-Rainbows; version 1.11. RAIND112 LZH Allows using Rainbow MS-DOS diskettes in 80-track, 5.25-inch drives on non-Rainbows; version 1.12. RBHIST85 ZIP Keeps a command history and blanks screens on DEC Rainbows. RDCPM-HD LZH Reads CP/M directories and files even from hard disk partitions. READER31 LZH Text analyzer for Rainbows. SCANV52 ZIP Virus scan version 5.2, scans disks and executables for viruses. SCANV63 LZH Virus scan, version 6.3 SCANV67C LZH Virus scan, version 6.7 SEDT3DOC ZIP Screen EDiTor version 3.3(348) documentation SEDT3DOS ZIP Screen EDiTor version 3.3(348) SEDT3KEY ZIP Screen EDiTor version 3.3(348) key definition files SIDEWRIT ARC Prints sideways from IBM PC compatibles to certain printers SORTF235 LZH Fast text sorting utility. SV900109 ZIP Silicon Valley Rainbow newsletters SWAPN12 LZH Swaps names of files. TABS21 LZH Converts between tab characters and spaces; removes trailing blanks. TETRISRB ZIP The game TETRIS for Rainbows; with the source code TIMEPARK ZIP Parks your hard disk after a specified period of inactivity TYPTUT ZIP Typing tutor for DEC Rainbows UE310150 ZIP MicroEMACS 3.10 executable for Hewlett-Packard 150s UE310ANS ZIP MicroEMACS 3.10 with ANSI screen controls UE310C ZIP MicroEMACS 3.10 "C" source code. UE310CMD ZIP MicroEMACS 3.10 macro command files UE310DOC ZIP Documentation for the MicroEMACS editor, version 3.10 UE310DOC ZIP MicroEMACS 3.10 documentation files UE310H ZIP MicroEMACS 3.10 "C" source code header files UE310IBM ZIP MicroEMACS 3.10 executable for CGA/EGA/VGA screens UE310MAK ZIP MicroEMACS 3.10 "C" source make files UE310OS2 ZIP MicroEMACS 3.10 executable for OS/2 UNLZEXE LZH Undoes LZEXE compression. V4N3ASC ZIP VARUG newsletter, volume 4, number 3 V4N4ASC ZIP VARUG newsletter, volume 4, number 4 V4N5ASC ZIP VARUG newsletter for September & October, 1990 V4N6ASC ZIP VARUG newsletter for November & December, 1990 VDE152 ZIP VDE editor & word processor VDE154 ZIP Versatile word processor for IBM and ANSI systems VEMM LZH Aids for managing extended memory WHERE31 LZH Searches all directories & archives for files. WHERE36 LZH Searches all directories & archives for files; a public domain utility. WHERE40 LZH Searches all directories & archives for files; shareware. WORM ZIP DEC Rainbow game WP50DEC5 ZIP WordPerfect 5.0 drivers for DEC printers WUTIL32 ZIP WUTIL version 3.2 hard disk manager for Rainbows WUTIL32S ZIP Source code for WUTIL version 3.2 XTRAC41 LZH Extracts specified lines from texts. ZIP-KIT9 LZH Auxiliary utilities for PKZIP. On Rainbows, MS-DOS 3.10b is needed; on-screen messages need Code Blue. FV127 and FV131 run on a Rainbow or other MS-DOS machine. SIDEWRIT requires Code Blue on a Rainbow. SIDEWRIT also requires a printer compatible with an Epson, IBM Proprinter, or Hewlett-Packard InkJet. The MS-DOS versions of VDE (1.52 and 1.54), as supplied, use screen codes like those of an IBM PC. These implementations of VDE run on a Rainbow under Code Blue with its '/V' option. However, if VDE is configured for ANSI controls, a 24-row screen, and fast scrolling, the program runs under Rainbow MS-DOS without Code Blue. For the purposes of running VDE on a Rainbow, a DEC LA50 qualifies as an IBM graphics printer. As Easy As version 4.0 runs on Rainbows equipped with MS-DOS 3.10b and Code Blue 2.01 with its '/V' option. However, the graphics features are not available on Rainbows. CLEAN-UP (CLEANP63 and CLEANP67) and virus scan (SCANV52, SCANV63, and SCANV67C) run on most MS-DOS machines, including Rainbows. However, the programs do not correctly analyze Rainbow memory, but claim to scan 640 000 characters of memory even if less is present. DESIGNER is set up for IBM BASICA, but may be modified to suit Rainbow GW-BASIC or other versions of BASIC since the source code is included. LIST versions 7.2A, 7.3D, and 7.4A ran under Rainbow MS-DOS with Code Blue and its '/V' option. If the version of MS-DOS was 2.xx rather than 3.10, then Code Blue's '/C' option was also needed, and LIST's 'M' command to trace for snow made the computer stop responding to keystrokes. Under MS-DOS 3.10, the 'M' command had no noticeable effect. The communication feature of LIST did not work when tried on a Rainbow. The LIST mouse driver was not tested. SEDT runs on most MS-DOS machines, including Rainbows, given at least 190 000 characters of memory. The VARUG newsletters are in ASCII form. V4N4ASC.ZIP includes graphic displays for Rainbows and LA50-compatible printers. The three versions of WHERE run on most MS-DOS machines, including Rainbows. DISKCACH and ENVIRON were not tested. ISLZEXE runs on most MS-DOS machines including Rainbows. LZEXE uses IBM PC codes. On a Rainbow, LZEXE requires MS-DOS 3.10b and Code Blue. Code Blue's '/V' option is required for a screen display, but not for other functions. MMDRIVE was not tested. On a Rainbow, for a full screen display with CKOT, use MS-DOS 3.10b and Code Blue with its '/V' option. If you can forgo the screen display, 3.10b and Code Blue are not necessary. The 80286 version of ARCA runs on an NEC V20 microprocessor. The floppy disk formatter QDR33D balked at an RX50 drive, though it did turn an RX50 MS-DOS diskette into the 40-track, single-sided format. DIAGS ran nicely on an old Corona portable computer. DIAGS ran on a Rainbow under Code Blue 1 with its '/V' option but gave incorrect information and did not print messages that were intended for a printer. DOG runs on most MS-DOS machines, including the Rainbow, but has trouble under MS-DOS 4. DIS300 retains most of its features under Rainbow MS-DOS with Code Blue and its '/V' option. FSPOOL, GS13, PC Zmodem, TIMEPARK, and HELPSB were not tested. HDDIAG did not run on a Rainbow. LJUP2 ran on a V20-equipped Rainbow 100A and LA50 printer. Since the LA50 is quite different from a LaserJet, the print-out was garbage. Modem Doctor did not work on a Rainbow. The MasterKey utilities (in MSTRKY17.ZIP) ran under Rainbow MS-DOS and Code Blue 1, but the disk editor had trouble with the Rainbow RX50 file format. The ANSI version of MicroEMACS 3.10 worked on a Rainbow in a brief trial. Other implementations of MicroEMACS 3.10 were not tested. ----------------------------------------------------------------------------------- Review: SupraModem 2400 External Modem By Wilson C.Y. Chang The SupraModem 2400 external modem is the cheapest modem of its kind I have seen lately. I tried one to see what you get for modest expense these days. The modem is produced by Supra Corporation 1133 Commercial Way Albany, OR 97321 United States Of America Telephone (503) 967-9075 (for orders) (503) 967-9081 (for technical support) Included with the modem is an operator's manual, an addendum with updates to the operator's manual, a reference card with a list of commands, an AC power adapter, a telephone cable, and a warranty registration card. I found the operator's manual reasonably complete and easy to read. I would prefer having an updated manual instead of the addendum correcting passages in the main manual. The modem comes with no communications software. I did not mind that lack; I have plenty of communications software and can get more. Besides, I planned on using the modem with various computers, and the software supplied with some modems is dedicated to certain hardware only. The package did include special offers of reduced rates or free trial subscriptions to GEnie (General Electric Information Services), OAG (Official Airline Guides) Electronic Edition Travel Service, Dow Jones News/Retrieval, and CompuServe. I have yet to take up any of these. I was struck by the small size of the modem. I measured it at 17.0 cm long, 11.6 cm wide, and 3.1 cm tall. I included the off-on knob and the rubber feet, but not the power supply, in the measurements. The small size offsets the claim that internal modems save desk space over external modems. The power supply plugs into a standard AC wall outlet and into the back of the modem, converting 120 volts of alternating current into 8.5 V AC and up to 1.35 amperes. The SupraModem uses Hayes-style AT commands. I say "style" because the Hayes SMARTMODEM 1200 I examined lacks many of the SupraModem's commands. Of course, the SupraModem operates at 2400 bits per second (b/s) while that Hayes was limited to 1200. Like other 2400 b/s modems, the SupraModem also communicates at 1200 b/s and 0 b/s to 300 b/s. I found that feature necessary for communicating with systems (like one local Datapac outlet) which are limited to lower transmission speeds. I tried the SupraModem 2400 with a DEC Rainbow 100A and an AT&T 6286 computer. Connection in either case was simply a matter of using a cable with a 25-pin male connector on one end and a 25-pin female connector on the other. I supplied my own cable. Connecting to a telephone line required a cable with line cord modular connectors at each; as I mentioned before, that cable came with the modem. The SupraModem 2400 has a non-volatile memory for saving preferred settings. Two different configurations can be saved. Up to four telephone numbers can also be saved in non-volatile memory so that the modem has a rudimentary dialing program in memory. Having a built-in dialer was a convenience while I used the Rainbow in terminal mode. There are no little switches ("dip switches") for modem settings, but then the non- volatile makes such switches unnecessary. The modem has a built-in speaker. The volume is controlled by software commands; there is no external volume control. The volume level can be saved in non-volatile memory, so the SupraModem (unlike some other modems I have used) did not annoy me with a too-loud speaker. When the volume level of my telephone's dialing was moderate, so were the sounds made by the remote system. The non-volatile memory stores the modem's reaction to the computer's data terminal ready (DTR) signal. I prefer to have the modem ignore this signal so that if a problem arises I can reset the computer without breaking the connection to the remote system. On other modems, this setting is determined by a dip switch or is fixed by manufacturer, and not necessarily fixed as I prefer. The option to control reaction to the DTR signal is a definite plus for the SupraModem 2400. The front panel had lights indicating whether high speed was used, the modem was off-hook, the terminal (that is, the computer) was ready, and other characteristics of a communication session. One minor problem: The off-on switch operated by being pushed in, and then popped out again, so that it had the same position whether the modem was on or off. The front panel lights told whether the modem was on, but I prefer to know even if the modem is not plugged in to alternating current. I used the modem for many calls to bulletin boards and the transfer of millions of characters of files in either direction. The SupraModem lagged somewhat in responding to commands. Otherwise, the modem behaved flawlessly as far as I could see. The telephone line I used was designed for pulses rather than tones, but I used the modem to gain access to tone-controlled services. This modem did not have MNP (Microcom Networking Protocol) ability for effectively higher communications speeds or error checking. That was not a problem for me since I did not communicate with a system which offered MNP, but some other people might be disappointed. I definitely liked the SupraModem 2400 external modem. I recommend it for other users' consideration. ----------------------------------------------------------------------------------- An Introduction To The C Programming Language By Jeffrey S. Katz (Editor's Note: This article is taken from the September, 1989, issue of CVLUG$OUTPUT, the newsletter of the Connecticut Valley Local Users Group.) The C language and its cousin, the UNIX operating system, are hot topics. Today we'll talk about C by relating some of its characteristics to the more traditional languages. What Is C? ---------- C was developed more or less concurrently with the UNIX operating system. YOU DO NOT NEED UNIX, OR KNOWLEDGE OF IT, TO USE C. C has comparatively few statements; mastery of it comes from using the building blocks in a clever way, not choosing from a list of 100 verbs. C is a well- supported native VMS language. With the VMS calling standard, you can write some of your program in your favorite language, and try a small part in C. There are personal computer versions of C to get started with, such as Borland Turbo C and Microsoft Quick C. The development environment is different for each C product, but the language itself is similar. Lines Don't Matter ------------------ The 80-character record format was pretty much passΘ when C came along, so ideas about one statement per line, or one line per statement, or special byte positions within a record, are all irrelevant here. A C statement ends with a semicolon (;). However, the way the statement meanders around your terminal screen until the semicolon appears is mostly a style issue. Conversely, leaving out semicolons is a typical problem for beginners. Blocks ------ Many C statements operate on a range of one other statement. A loop is defined as controlling the statements after itself. The block concept lets a group of statements be considered as one. A block starts with an open brace ({) and ends with a closed brace (}). A Program --------- A C program consists of functions. A function is a function name, a list of arguments enclosed in parentheses, and a block. Functions are called by name. Many things that are verbs in other languages are functions in C. main() { printf ("DECUS is good for you\n"); } An analysis of this program shows: A function called 'main' is being defined. It has no arguments--there's nothing between the parentheses. An opening and closing brace, encapsulating the function. A call to another function, printf. Function calls are the function name followed by the arguments in parentheses. The argument to printf is a string, since it's enclosed in quotes. There is no read or write statement in C. There are a bunch of standard functions, such as printf (print formatted), and scanf (scan, or read, formatted). As I said, the language is terse when it comes to verbs. The '\n' indicates a new line is needed. Without it, no carriage return-line feed sequence will occur after the input-output operation. There's a semicolon at the end of the end of the line, to terminate the statement. The only thing special about this program is the function name. The main or root program, which must be part of every program, has the function name 'main'. Variables --------- C is strongly typed. Every data item needs a type declaration. The basics are: C | FORTRAN | COBOL ----- | ---------- | ---------------------------------------- int | INTEGER | PIC 9 (technically, USAGE COMPUTATIONAL) float | REAL | PIC 9 (typically USAGE COMPUTATIONAL-3) char | CHARACTER | PIC X short | INTEGER*2 | PIC 9 (as for int) double | REAL*8 | PIC 9 (some machine-dependent USAGE | | COMPUTATIONAL clause) Assignment ---------- The equal sign is used: Pay = 60.40; Taxes = Pay / 2.0; Loops ----- Every language needs loops; otherwise programs couldn't run for a long time without the programmer writing a lot. C has the 'while': while (temperature > 90.0) { ac = ac + 2.0; set_ac (ac); temperature = sense_temp(); } The block is executed, since it is the statement after the 'while'. The three statements are executed in a loop until temperature is 90 or less. Now is a good time to point out that C is usually written in lower case as is its relative, UNIX. Many C compilers differentiate between variables made of upper and lower case. The more traditional loop, similar to the FORTRAN 'DO' or COBOL 'PERFORM' is for (vaxmodel = 6000; vaxmodel <=6500; vaxmodel = vaxmodel + 100) printf ("Sales rep: You've outgrown your system and need a %6d", vaxmodel); The first phrase in the parenthesized list after the 'for' statement is the initial one, executed once at the beginning of the loop. The next phrase is the condition which must be true for the loop to execute. When it is not true, the loop is completed. The third phrase is re-evaluated every time through the loop. The scope of the loop is the statement (or block) after the closing parenthesis of the 'for'. Something new here is the format descriptor in the 'printf' string. Items beginning with a '%' are interpreted as descriptors for variables, in a manner similar to FORTRAN FORMATs. Integers are printed with '%d', '%3d' being analagous to FORTRAN 'I3'. A floating point conversion of '%10.2f' resembles FORTRAN's 'F10.2'. Other Correspondences --------------------- To get some ideas transferred quickly, let's try a page from an imaginary C to FORTRAN dictionary: C | FORTRAN ------------------------- | ------------------------------------ | char annie[20]; | CHARACTER ANNIE(20) | float xmatrix [10] [10]; | REAL XMATRIX(10,10) | scanf ("%4d",&flux); | READ (1,10) FLUX | 10 FORMAT (I4) | #define AREACODE 203 | PARAMETER (AREACODE = 203) | #include turbinedef.h | INCLUDE 'TURBINEDEF.FOR' | if (x != y) q = 4 | IF (X .NE. Y) THEN else | Q = 4 q = 5; | ELSE | Q = 5 | ENDIF | if (a == b || c == d) | IF (A .EQ. B .OR. C .EQ. D) e = f; | THEN | E = F | ENDIF | leptons = 4; | LEPTONS = 4 mesons = leptons++; | MESONS = LEPTONS | LEPTONS = LEPTONS + 1 | leptons = 4; | LEPTONS = 4 baryons = ++leptons; | LEPTONS = LEPTONS + 1 | BARYONS = LEPTONS There are many other programming goodies such as the 'switch' statement, which is a 'case' statement for those familiar with the term; if not, it's a multiway branch and select, similar to using a stack of FORTRAN 'IF-THEN-ELSE-IF's. In a brief article, it's hard to illustrate lexical scoping, but here's an idea of the flavor of the concept. Variables exist only within the range of the function defining them. For a variable to be shared in the sense of FORTRAN COMMON, it is declared outside a particular function. Often, such a declaration is made before the 'main()' function declaration: int global1, global2; main() { char yoda, luke, hans; int sequel, nextgalaxy; sequel = 3; global1 = 4; sequel = nextgalaxy(sequel); } int nextgalaxy(n); { int n; return (n + global1); } Here we have a main program and a function (subroutine). There are two global variables which are available to both functions. The variables 'yoda', 'luke', and 'hans' are local (automatic in the vernacular) to the main program. So is 'sequel', but it's passed as a formal argument. C functions serve as both FORTRAN subroutines and functions. For the function name itself to return a value, the 'return' statement is used to set the value of 'nextgalaxy'. To C Further ------------ I hope this article covered enough to get you interested (or decide you're positively not interested). To learn enough to be dangerous, you'll need a little more knowledge of the language. The standard book for C is by the original authors of the language. It's called "The C Programming Language" by Brian Kernighan and Dennis Ritchie, published by Prentice-Hall. It's a paperback, so the price might be reasonable. Another companion book, "The C Answer Book" by Clovis Tondo and Scott Gimpel has solutions for the exercises in the first book, and is put out by the same publisher. Try a university bookstore. There are many other books about C in your local bookstore, so you'll have to judge what else is helpful after you get the two basics. To get around in any particular implementation of C, you'll also want the vendor's manuals. On UNIX, there's another program called 'lint'. Lint is a strict syntax checker for C, and it is a good idea to run your program through it. It can be so picky that almost every program has some warning or informational note, but it beats run-time debugging. The best way to learn a language is to need to use it. The next time you need a small utility program, such as a cryptogram solver, write it in C. ----------------------------------------------------------------------------------- Video Boards (Editor's note: This article is taken from the VAXnotes section of the DECUS Canada MicroVAX, MUKLUK. The article does not mention DEC Rainbow video. The standard Rainbow video system is designed for text only, and offers 24 rows and 80 or 132 columns. The optional graphics board offers 240 rows and 384 or 800 columns of dots in graphics mode. With the graphics board and DEC-supplied color monitor, a Rainbow 100A can produce 1024 colors, while a 100+ or 100B can produce 4096 colors.) MAIL> Note 32.2 PC graphics boards 2 of 14 EISNER::KENNEDY "Terry Kennedy" 79 lines 7-DEC-1988 02:43 -< Short summary of adaptors >- > I am a novice with PCs. Can someone give me a clear but brief explanation > about the various graphics options on PCs? In the beginning: MDA - Monochrome Display Adapter - 80x25 monochrome text with bold, blink, reverse video, underline. NO graphics ability. TTL interface. CGA - Color Graphics Adapter - 40x25, 80x25 text, attributes as above except no underline. Capable of producing 8 colors in 2 intensities. Has 320x200 graphic mode, using one of two choices of color sets: (red/ green/brown or cyan/magenta/white), 640x200 graphic mode in black/ white only. TTL, composite interfaces. The Middle Ages: HGC - Hercules Graphics Card (and clones) - Added mono graphics to the MDA. Not program-compatible with other graphics modes, but widely supported. TTL interface. PCjr - Added the ability to display all 16 colors in CGA graphics modes. Also introduced some new modes, ignored by all until the EGA came out. AT&T (Olivetti) 6300 and 6300+ - CGA in 640x400, with software in ROM to pretend to be a CGA. Works well most of the time. (It better, since the video is part of the motherboard and you can't get rid of it [mostly]). Assorted other boards which emulated one of the above, or enhanced one of above (usually CGA) modes. Examples: STB, MAI, Plantronics. Recent History: EGA - Enhanced Graphics Adapter - Added 640x350 graphics, 16-of-64 color selection to CGA (also a superset of PCjr) modes. Went nowhere due to price ($1200) and memory limitations (base memory = 64 k) until Chips & Technologies Xeroxed the chipset and sold cloning kits to everybody on the block. Now considered the bare minimum for a color display. Can drive (and emulate) monitors for MDA and CGA. Some clones emulate HGC as well, but emulation is imperfect in most cases. TTL output, requires special (EGA or multi-sync) monitor for new modes. 'Super' EGA - not content with cloning the board, other vendors added higher resolution (commonly 640x480, although 800x600 is also seen). There is no standard for how you get to these modes, though, so make sure your software will work with the board you're looking at. Some vendors include 132-column ability. Still TTL (although ATI offers composite). PGC - Professional Graphics Controller - An EGA superset (256 colors) with an on-board CPU for graphics assist. Nobody bought one. Hercules Color Graphics Card, Hercules Graphics Card with RAMfont - attempts by Hercules to catch up with a market that has passed them by. AT&T (EPIC) boards - The ICB, VDA and Targa - These boards manipulate video in near-real-time, can grab images from TVs and PCs, etc. Very expensive, support is medium to poor. Require another display adapter in the system for normal PC stuff. The new stuff: VGA - The latest from IBM (and the cloners). Legitimizes the 640x480 mode of the Super EGAs. Adds 256 color display (out of several zillion). Analog output. Some cloners have already come out with super VGAs, with the upper limit currently about 1024x768. These boards may have up to 1/2 megabyte of memory just for the display (256K is standard). Requires a PS/2, multi-sync, or 8514 monitor for new modes, clones will run on other monitors, but not in the advanced (new) modes. MCGA - A low-end VGA implementation found in the PS/2 25 & 30 models. 8514 - IBM's latest try at the PGC. Nobody is buying these either. A super VGA with a fast 386 is better for most things (8514 support is very scarce). With the cost of a VGA board (street) under $200, I don't see any reason to get anything else today. You can always start with a cheap monitor and upgrade later if cost is a problem. End of note Note 32.3 PC graphics boards 3 of 14 EISNER::KENNEDY "Terry Kennedy" 10 lines 7-DEC-1988 02:47 -< What runs on what >- > Will a program written for VGA run on EGA, etc.? Anything listed as a superset of a previous board in the previous reply should run software for the older board. Most commercial software today will run on EGA or VGA. Some things (like paint programs) are VGA-specific. Note that you have N manufacturers trying to write code for their boards to emulate the IBM board. There are bound to be some bugs and quirks in various things. Be very choosy when selecting a VGA card (ask if you want my opinions). End of note ----------------------------------------------------------------------------------- Questions And Answers Do you have a computer-related problem? Send it to us. We can publish it, and if we do not know a solution, perhaps someone else in the users group can provide one. QUESTION: When I use fanfold paper in my printer, a row of perforations sometimes catches on the paper bail, wrecking the run. How can I avoid this problem? ANSWER: You can try lubricating the paper bail around its rubber rollers. However, the solution we find best is to move the paper bail away from the platen. Some printers (the DEC LA100, for example) force you to do so when you install the tractor, and the procedure works with other printers we have tried. QUESTION: I have a computer which runs MS-DOS. I have learned that I can abort commands by entering either control-C or control-Break. Is there any difference between the two? ANSWER: MS-DOS and IBM PC-DOS have a type-ahead feature; a certain number of keystrokes may be made ahead of time, and the keystrokes stored in memory and processed in turn. On an IBM PC and many other computers, if you enter control-C, the command to abort will wait in turn until preceding keystrokes are accepted. Entering control-Break clears all keystrokes from memory, and aborts at once. Unaided Rainbow MS-DOS does not allow aborting by control-Break. Under MS-DOS 2.01, control-C aborts at once, just like control-Break on an IBM PC. Under later versions of Rainbow MS-DOS, the memory-resident utility RB-BUFFR makes control-C equivalent to an IBM PC's control-Break. QUESTION: I need a new power supply for my modem. The modem takes an external transformer which converts normal wall current (120 volts AC) to 9.5 volts AC (not DC). Where can I get such a power supply without buying another modem? ANSWER: We made many telephone calls before getting the answer. We found a 120 volt AC to 9.5 volt AC power supply at a local Gandalf Data Limited service center. Gandalf is a manufacturer of modems. The power supply we found at the Gandalf center fits some other manufacturers' modems, but you will have to check whether your modem has a compatible connector. Generally, we suggest you contact a modem service outlet, preferably for your brand of modem. ----------------------------------------------------------------------------------- Buy, Sell, Or Swap This section is presented as a service to members. There is no charge for advertizements placed here, though donations will be accepted. Only items related to computing will be advertized; if you wish to sell an old car, we respectfully suggest that you publicize elsewhere. Advertizements are not accepted from suppliers. In accordance with DECUS policy on commercialism, we do not print prices. Ads should preferably be submitted to the editor in writing or as ASCII computer files, but may also be phoned in. ---------------------------------- AVAILABLE: The Chilliwack Progress newspaper has three rack-mounted RK05J disk drives to give away free of charge to computer clubs or radio buffs. Contact Dave Pilgrim at (604) 792-1931 weekdays. AVAILABLE: Kwantlen College is clearing out a stock of DEC Rainbow and DECmate accessories, including graphics packages, floor stands, and cables, as well as Rainbow and DECmate software such as Select-86, Multiplan-86, Multiplan-80, MBASIC-80, CP/M-86/80 version 2.0, MS-DOS 2.05, Peachtree List Manager, and Poly-Com communications. Some items are in the original unopened packages. Contact Randy Bruce at (604) 599-2068. FOR SALE: Rainbow 100 with 256 k of memory, Multiplan, WPS-80 word processor, accounting programs, and other software. Contact Doug Nicol at (604) 792-0025. FOR SALE: Poly-XFR CP/M communications software for Rainbow 100; the software is in the original package with all documentation. Three 65 536-character DRAM (memory) chips. One serial-to-parallel interface. These items are just taking up space now, so all offers will be considered. Telephone David P. Maroun at (604) 792-4071. FOR SALE: Peachtree business modules for MS-DOS: PeachCalc spreadsheet, general ledger, accounts payable, accounts receivable, personal calendar, job cost system, and inventory control. Any offer will be seriously considered. Note: These modules require Code Blue and maximum memory to run on Rainbows. Contact David P. Maroun at (604) 792-4071. FOR SALE: One memory expansion board, nominally 192 k, for a DEC Rainbow. Contact Ken Alger at (604) 390-4482. FOR SALE: DEC LA50 printer; needs some repair. Contact David Camp at (604) 640-4104 (work) or (604) 737-1904 (home). WANTED: Read-only memory (ROM) chips to allow a DEC LA100 printer to print 8-bit characters and to print letter-quality text at twelve characters per inch. Telephone David P. Maroun at (604) 792-4071. ----------------------------------------------------------------------------------- What Do You Think Of This Issue? Please tell us what you liked and did not like. The best articles were:__________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ The worst articles were:_________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ Comments or suggestions: Send your opinions to The Editor, VARUG Newsletter, 9395 Windsor Street, Chilliwack, BC, Canada V2P 6C5.