========================= C-128 Compatibility By: Carl F Howard [CHUCK.WAGON] 09-19-1987 ========================= This is an article on the aspects of compatibility of the C-128 and other operating systems and software available to facilitate the importing and exporting of data. This article centers on the CP/M mode of operation although the discussion will cover the various modes of the C-128 as well. Although the C-128 utilizes 8-bit CPU's it's diversity as a personal computer for home and small business purposes is one of it's main Assets, and I am sure many new users of the machine aren't even aware of the capacities available to them. Aside from playing your favorite games in C-64 mode the Native 128 80 column capabilities allows much convenience for the use of productivity applications to the new user. There is already a wide base of Word Processing, Data Base and Spread Sheet Software available for use. Additionally by utilizing the CP/M mode of operation users can take advantage of Business Applications and a huge base of public Domain Software as well. Also, it is possible to use your C-128 to process data brought home from the office or school which was created on an MSDOS machine. This article will help you become aware of the various different disk and data type formats and the software available to convert data for your particular application. First it is necessary for the new user to understand a little about the way information is stored in the commodore computer and how it differs from other types of computers used in the U.S. As you are aware all data utilized by a computer is essentially processed in binary numbers in the forms of zeros and ones. This represents the on and off state of an individual transistor switch in the intergrated chips of your computer. This is simple enough as far as it goes but how does the computer know when you press a key on the keyboard what your pressing and what it means? Well each key has a numeric value assigned to it. The value can be expressed in Decimal, Hexadecimal or binary form. And it is this value which is converted to a binary number that allows the computer to distinguish what key is being pressed and what it means. Most computers used in the U.S. use a standard code called ASCCI which assigns a value of decimal 1 to decimal 128 to characters used by them. Commodore in their unique wisdom however chose not to use this standard an developed a character set unique to there machines using decimal codes 1 to 256. So in order to use data created by other machines it is necessary to convert it too PETASCCI code a form which your Commodore computer can understand. Aside from the data differences Commodore also chose to use a different way of storing information on their floppy disk as well. Mostly their reason for this was to build a cheaper disk drive. They use GCR format as opposed to MFM format for the rest of the U.S. computer industry. I won't go into the difference here but, it is nice to know that the 1571 Disk Drive has the capability of reading and writing to both formats with the use of the proper software. We'll get into this more bellow. The thing to remember here is that all Native Commodore operating systems (home computers) including CP/M use the GCR format. Well armed with this information what else do we need to know? For one it is important to know whether you are using a single or double sided disk format. For another it is important to know which operating system (or disk drive) your disk was formatted on. The types of disk formats we will be discussing here are the following: a. C-64 Single Sided 1541 b. C-128 Single Sided 1571 (1541 compatible) c. C-128 Double Sided 1571 (not 1541 compatible) d. C-128 CP/M (GCR) 1571 Single Sided (1541 compatible)) e. C-128 CP/M (GCR) 1571 Double Sided (not 1541 Compatible)) f. C-128 CP/M (MFM) IBM (CP/M-86) Single Sided 1571 (not 1541 Compatible)) g. C-128 CP/M (MFM) IBM (CP/M-86) Double Sided 1571 (not 1541 Compatible)) h. MSDOS IBM Double Sided (9 tracks) DOS Version 2.0 or higher. As you can see I have listed the Disk types in upward compatible order. Commodore did develop a CP/M version (2.2) for the C-64 which required an add on cartridge to implement and as such I've included it in our list although we will be discussing the 128 Version here which is CP/M + (Ver 3.0) and takes advantage of the 128's Banked Memory (additional 64k as opposed to only 64k for Ver 2.2). The Stock C-128 CP/M Operating System which comes with the computer is capable of reading and writing formats d. e. f. & g. noted above. The stock system is also capable of reading Kaypro And Epson Formats as well. The System will automatically identify the disk type in current use in the lower right hand corner of your monitor. Note when a disk format other than a 128 Single or Double Sided format is used the user must tell the system whether or not the non-128 formatted disk is a single or double sided disk. This is done by pressing the left or right arrow keys on the top row next to the function keys. Failing to identify the correct format can cause disk read and write errors so be sure to properly set the system for the correct format. There are Two Public Domain Programs available that will enhance the C- 128 Systems ability to read write and format other CP/M formats. They are Called NFORMAT.COM and UNIDRIVE.LBR File numbers 1554 and 2682 in the C-128 library number 34 on the CP/M R.T. NFORMAT will allow you to format all of the formats indicated above and Osborne DD formats as well. Unidrive will allow you to read/write up to 10 formats out of a menu of 25 different formats not supported by the stock O/S. Although there are more than 200+ CP/M formats these 25 will surely enhance your systems capabilities and cover a range of the more popular formats you will encounter. More than likely at some point you will want to transfer data you have created on your C-64 or 128 in native mode. The stock system can't do this. But don't get discouraged. A real Nifty Program to read and transfer/convert Data from your Commodore disk has been put in the Public Domain by Rob Tiloston called RDCBM21.LBR. This is file number 3733 on the CP/M R.T. It will allow you to transfer binary (program) files or sequential files you have created in native mode to your Ram Disk or second Disk Drive while you are in CP/M operating mode. The program will also convert PETASCCI to ASCCI for you as well. CP/M uses ASCII files and your Commodore text files will have to be converted for you to use them in CP/M mode. The program is very helpful in this respect and eliminates your having to use other utility files for the conversion. The other nice feature of this program is that you can transfer CP/M program files you have down loaded with your Native terminal program to a Commodore formatted disk directly to a CP/M disk or your RAM disk while in CP/M mode. This is a much eaiser way of accomplishing transfers than some of the earlier transfer programs that came out in the beginning days of C-128 CP/M. The program is menu driven and easy to use and I highly recommend it for anyone just beginning in CP/M mode. While we're on the topic of Commodore to CP/M transfers I'll shift back into Native mode transfer programs for just a moment. There are 2 programs that are available here on GEnie for use in 128 Mode to facilitate Disk to Disk transfers of Data. One is a DEMO program of a commercial program called Big Blue Reader, File number 2264 in Library 9 of the Commodore R.T. and it will allow you to view MSDOS Data files on your 128. The actual program will implement full file transfers and I believe the current version also supports CP/M transfer as well. The suggested retail price is $29.95. The other Program is called CROSSLINK2.LBR, File number 3023 also in Library 9. Cross Link is a fully implemented menu Driven Disk to Disk (2nd Drive optional) transfer program that will make just about any kind of transfer/conversion you can think of. It will handle CBM, CP/M and IBM Disk formats and do ASCCI PETASCCI conversions as well PRG and Screen file conversions too. This means that it will convert just about any Commodore text file format into a usable CP/M or MSDOS format that you require. You can also use it to convert different text file formats used by the various Commodore word processing applications programs too. It is an absolute MUST HAVE utility for any one using more than one type of word processor on their Commodore computer. The major draw back with using either of these two programs though is that they are limited in the size of the files that they can transfer to about 200 disk blocks or 40k of memory. This is because they store the data being transferred in a RAM buffer and Don't transfer the data directly. This can be overcome by splitting a larger file into smaller ones for text files but you will not have this option in the case of a Program ARC or LBR files which can't be split. For larger files you are going to have to use the RDCBM program above or employ a direct conversion method of tranfering your data such as a Null Modem Cable (See my article in the June issue of t...
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