Msg: 3538 *Conference*
12-07-92 19:00:28
From: RICHARD HANSON
To : RICK HENDRIX
Subj: REPLY TO MSG #3537 (HELP WITH FILE TYPES)
Rick: A .CO file is a machine language file. In other words, it's a file written in the language of the processor, i.e., Intel 8085, in the case of our Model T's. Machine language programs (m/l) are really neat, but can be a pain in the ... it you don't handle them properly. M/L files run much, much faster then .BA files (tokenized BASIC files) because the M/L file does not need to be interpretered, line by line, to run. The processor simply follow the commands in the M/L file, directly. Also, M/L programming is much closer to the processor then .BA programming, giving the program much more control over the functions of the processor; thus more "trick" are available to the M/L programmer. HANDLING THE .CO FILE IN A MODEL T M/L files (.CO) run (execute) from one area in memory (RAM), only. A .CO file appearing in the menu as filename.CO is actually stored in a separate area of memory then its running version; a duplicate copy. Thus, when you run a .CO file that you see in the menu, that menu-copy is copied to this special place and executed from there, i.e., two copies taking twice as much room. Some crafty M/L programmers discovered that there are other places in RAM that they could "trick" the processor into runnning .CO file from. One of these areas is the LCD buffer; a place in RAM used to drive the screen (LCD = liquid crystal display). The discussion, thus far, is sort of technical. Let's explore facts a users needs to know to actually use .CO files. 1) Each .CO file contains 3 addresses: Top, End, Exe. It is important to document these addresses for each .CO file you wich to play with. Documenting these three numbers is very easy. Assuming the .CO file is visible in your menu, go into BASIC and issue the following commands: CLEAR0,MAXRAM LOADM"filename.co" The first command simply clears that "special place" of any .CO file residing there. We don't want cold starts, do we? Okay, remember that command. The second command simply attemps to load the .CO file named filename into that area. Of course, it can't because we have not "opened" enough RAM for its loading, so it will simply present you with those three numbers, then issue the error code, OM? Error. This means Out of Memory but is nothing you need to worry about. The thurd step is to write those numbers down, keeping an eye on the "Top:" number. That's the one you need to reference whenever you wish to run this particular .CO file. Lastly, to run your .CO file, do the following: CLEAR256,topnumber LOADM"filename.co" MENU ...now place your cursor over your .CO file and hit <enter> Now that we've come this far, let's explore the use of more than one .CO file at one time. There are two ways to run two ore more .CO files in the same machine, i.e., to run one, then the other, then another or back to the first. 1) For each .CO file, go into BASIC and issue the commands CLEAR0,MAXRAM and CLEAR256,topnumber. Return to the menu and run that .CO file. To run the second one, go back into BASIC and reissue the commands, using the second .CO file's topnumber in place of the first .CO file's topnumber. In this way, you will clear out the old, then open up the correct space for the loading and running of the new .CO file. Keep track of all this and you will probably never experience a .CO file conflict, leading to a cold start of your Model T. Note: You will find several multiple .CO file handling programs in our wonderful online library. For those reading this thread, who do not yet have library access, you are REALLY MISSING OUT!!! And for just $12 a year, too. Heck, you've probably paid more for a hair cut. Sorry about that... just getting a commercial in, here. 2) Most .CO files can be moved within that "special place" allowing room for more than one to be "stacked" on top of each other. This is just like stacking appartments. Each appartment (.CO file) has a front and rear door. Appartment dewellers use their separate doors to enter and exit their appartment. Thus, each .CO file, properly stacked, may be entered and exited without accidently going into the other .CO file. Stacking .CO files is actually quite easy with some of the .CO file stacking utilities in our ... wonderful online library (see commercial above) ... and knowledge of ... those three numbers assocated with every .CO file. For further information about .CO files, see (6)TechRef (D)ownload MLCODE.DOC edited by our own man-about-town, Mr M/L file manipulator, the organizer behind our ... wonderful online library ... none other than Robert Benson, CoSysop and Online Librarian. Yo! Take it a way, Bob! Your last question asked if you can use .CO files without a disk drive. The answer is, yes. A disk drive, like a tape drive, or using another computer, is simply a device for saving and loading files. There are 3 filetypes stock Model T's develop and use, i.e., .DO (text files, Aka: ASCII files), .BA (Microsoft tokenized BASIC files, requiring execution within the BASIC interpreter), and .CO (machine language files--the subject of this discussion). You may, however, run into a few other filetypes like .CA (Lucid spreadsheet files) and a few others. In all cases, you do not "need" a disk drive to use any of these files. Note: ... no make this a BIG NOTE: Always store your files to "some" storage device before messing around with .CO files, or any file for that matter. It's a matter of practicing safe computing. We are the lucky few who deal with cold starts these days. Let's get into the habbit of protecting ourselves, so we may "not fear" the cold start. It's like being ready for an earth quake. Quakes are wonderful experiences if you've protected yourself. Believe me, I enjoy earth quakes, and I do not fear a cold start. Hope this helps. Again, the dissertations I've writing these days in response to online questions has more to do with helping as many of our members as possible. Thank you for your questions and the opportunity to offer some assistance. -Rick-