============================================================================== [ THE KAY*FOG RBBS | Filename=CPM-CC27.ART | posted 07/05/86 | 200 lines 11k ] The CP/M Connection Originally published in by Computer Currents Ted Silveira 5720 Hollis Street (copyright and all rights reserved) Emeryville, CA 94608 May 20, 1986 Z: THE FINAL CHAPTER (FOR NOW) Now that I've talked about the _what_ of the Z-system, let me say a little about the _how_. Let's start with an overview of what happens when you install ZCPR3 (or ZCPR3 plus ZRDOS) on your CP/M computer. The typical CP/M computer has 64K of RAM (random access memory)-- that's actually 65,536 bytes (because 1K equals 1024 bytes). You can imagine this 64K RAM as a single stack of 65,536 pigeonholes or mailboxes, piled one on top of the other, each mailbox containing a single byte of information. Figure 1 shows how this RAM is allocated in a typical CP/M system. At the very bottom of RAM (addresses 0-255) is a reserved block of 256 bytes used by CP/M. The rest of the CP/M operating system lives in the uppermost section of RAM, taking up about 8-9K. The space between the reserved block at the bottom and CP/M at the top is the _transient program area_ (TPA), the space in which programs like WordStar, SuperCalc, and dBase II run. As you can see, the CP/M operating system itself is divided into three parts. The CCP (console command processor) interprets commands entered at the A> prompt and contains the built-in command such as ERA and DIR. The BDOS (basic disk operating system) handles things like writing and reading disks, creating and erasing files, and sending characters to the screen. The BIOS (basic input/output system) works intimately with the computer hardware, turning BDOS commands like "open a file" into "move the disk drive head of drive A to track 1" and so forth. Figure 2 shows the same typical CP/M computer with the Z-System installed. Three things have happened. First, ZCPR3 has replaced CP/M's standard CCP. Second, ZRDOS may or may not have replaced CP/M's standard BDOS (it's optional--see last issue's column for a brief description of ZRDOS' advantages). Third, the entire operating system has been moved lower in memory to make room for the ZCPR3 buffers and command packages. Because the operating system has been lowered, the TPA is now smaller by anywhere from 1K to 6K or more. That's the overview. When it comes to installing the Z-System on your computer, you have three routes you can take, four if you have a Kaypro. [Manual] The manual installation is the most difficult and yet the most flexible method. (If what follows is too technical for you, just skip it--there are easier methods.) Essentially, you start with the full set of ZCPR3 source files and build a Z-System of exactly the size and features you want. To do this, you need to know some assembly language, have a macro assembler (like Digital Research's MAC or Echelon's own ZAS), and know something about your computer's BIOS. Briefly, these are the steps. Collect the ZCPR3 source files and documentation. Then select the ZCPR3 features you want--you don't have room for everything. Next, figure out how much space you need for these features--how much for the FCP, the RCP, and so on. You work by cut-and-fit--do a trial assembly, check the size, juggle the numbers, do another trial assembly. Once you have the size set, use the CP/M utility MOVCPM to move the operating system lower in RAM to make room at the top of memory for ZCPR3's buffers and command packages. Then add a short routine to your computer's BIOS to set all the ZCPR3 buffers to the proper values on startup. Finally, assemble your chosen ZCPR3 package into a HEX file and use DDT to merge it with your new, smaller CP/M system, creating a new system image that you'll use to SYSGEN all your disks. [Semi-Automatic] Through bulletin boards and users groups, you can find a number of ZCPR3 installation "kits" for various computers. These kits are basically manual installations in which the hard work has already been done by someone else. What you get in one of these kits is a set of already assembled ZCPR3 files. You must created a smaller CP/M system with MOVCPM and then merge the kit files with it using DDT. None of the kits I've seen requires that you know any assembly language, only that you know how to use DDT, MOVCPM, and SYSGEN. Obviously, this installation is easier than the manual one. The drawback is that both the system size and the ZCPR3 features have already been selected--you can't change them without getting the ZCPR3 source files and reassembling them. But if you find a kit that has the features you want (and most do have a good selection), you're in business. [Automatic] Echelon, Inc., the distributor of ZCPR3, now offers automatic installation packages starting at $49.95 (and going up, depending on whether you want ZRDOS and whether you get the ZCPR3 utilities from Echelon or from public domain sources). This automatic installation really is almost automatic. You copy the master disks (consolidating files on one disk if you have room), boot up the copy, and then run a SUBMIT file by typing [SUB ZCCOM] at the A> prompt. As the SUBMIT file runs, it will create the various files you need. At the end of its run, it will run a terminal select program so that you can install ZCPR3 for your terminal type. Then the SUBMIT file passes control to your new system. This method gives you a slightly different kind of installation from the manual and semi-automatic ones. You end up with a COM file (Z.COM or Z3.COM) that contains your Z-System. You run this program from the A> prompt, and it loads your Z-System. You can set your disks to automatically run this COM file on any cold boot, so that you don't have to bother with running it yourself. You can also exit this Z- System at any time and return to normal (drab) CP/M by running a little program called ZCX.COM. There are two main drawbacks to this method of installation. First, you have to pay for it (though the price is certainly reasonable). And second, as in the semi-automatic installation, you don't have any choice of features or system size--you take what you get. The package has a good selection of features, and you can always substitute a new RCP (resident command package) or FCP (flow command package), but it's simply not as flexible as a manual installation. [Bootable Disks] Kaypro owners have yet one more choice, the easiest installation of all. Echelon now sells a "bootable" Z-System disk (including ZRDOS) for most Kaypros, including those with the Advent TurboROM and all stock Kaypros except those with the U ROM (CP/M 2.2u). To make this installation, you just put the Echelon disk in the A drive and hit the reset button. The computer will boot up the Z-System and run an installation program that gives you a choice of installing one of three versions of the Z-System. Choose one, put a blank disk in your B drive, and relax. The rest of the installation proceeds automatically. And unlike the automatic installation method I mentioned above, this method gives you a Z-System that boots up like any normal disk--no extra COM file to run. (Also, this package comes with a manual that's better for beginners than the usual Z-System documentation.) The drawbacks are the same as those of the previous method. You have to pay for it, and you have less flexibility than with a manual installation (though you do get to choose from three different-sized systems). [Final Words] The Z-System as a whole does have some possible drawbacks. First, because the Z-System takes more room than standard CP/M, there's always a chance you may encounter a conflict with some other program (i.e., one that wants more memory than is available with the Z-system installed), especially if you're also running a memory- resident program like SmartKey or Write-Hand-Man. Almost all the major commercial and public domain programs I know of work fine, including WordStar and dBase II. Second, it takes some time to learn your way around a full Z-System with menus, aliases, and all the trimmings. But you don't need to use all the Z-System's power right away, and learning Z is considerably less difficult than learning to use WordStar, for example. Third, the Z- System documentation isn't as good as it could be. It's full of detailed information, presented in an orderly and consistent way, but it's too dense to be readily accessible to beginners. Partly in response to this problem, Echelon maintains a list of "good neighbor helpers" (people willing to give advice on various systems) and puts out the _Z-News_, a biweekly newsletter. There's also a very large network of Z-Nodes, bulletin boards dedicated to exchanging information about the Z-System. Overall, ZCPR3 and the Z-System are tremendous improvement over standard CP/M. As I've said before, the Z-System is a computer supercharger--it makes many things easier and makes other things possible that weren't possible before. Once you try it, you won't go back. Information on ZCPR3 and accompanying programs: Echelon, Inc. Main Echelon/ZCPR3 bulletin board: 855 N. San Antonio Road Z-Node Central - 415/489-9005 Los Altos, CA 94022 415/948-3820 FIGURE 1 (Typical CP/M RAM) FIGURE 2 (Typical ZRDOS RAM) (approximate only) (approximate only) ------------ -CP/M OPERATING SYSTEM- ------------ | BIOS | basic input/output system | buffers | space for ZCPR3 buffers, |----------| | | RCPs, FCPs, etc. | BDOS | basic disk operating sys |----------| |----------| | BIOS | basic input/output system | CCP | console command processor |----------| |----------| |BDOS/ZRDOS| standard BDOS or ZRDOS | | |----------| replacement | | | ZCPR3 | ZCPR3 replacement for | | |----------| standard CCP | | | | | | | | | | | | | | | | | TPA | transient program area | TPA | transient program area | | (usually 55-56K) | | (typically 50-54K) | | | | | | | | | | | | | | | | |----------| |----------| | reserved | | reserved | ------------ ------------ ------------------------------------------------------------------------------ Ted Silveira is a freelance writer and contributing editor to several computer-oriented publications. He appreciates suggestions or feedback and can be reached through the KAY*FOG RBBS (415)285-2687 and CompuServe (72135,1447) or by mail to 2756 Mattison Lane, Santa Cruz, CA 95065. ------------------------- End of CPM-CC27.ART Text -------------------------