ADDITIONAL INSTRUCTIONS FOR TDD2PC.2DR Howard Sprow 73625,365 2/2/89 The original version of TDD2PC.2DR was intended for use with a 2 drive interface connecting a TDD and an IBM PC running Traveling Software's Booster- Link to emulate another drive. Since then I have experimented with Len Tucker's PC program, M100CO.EXE, in the M100SIG's DL 9. This program does essentially the same thing as Booster-Link for only the cost of connect time to download it. Just as with Booster-Link, this program can use multiple directories on the PC disk so you can backup several TDD disks to their own directories on each PC disk. In order to make TDD2PC.2DR work with M100CO, I had to make several additions to the original version. The current copy of TDD2PC.2DR in DL 9 has these changes. M100CO.EXE is a compiled BASIC program and has some trouble keeping up with the data flow when run on a standard 4.77 MHz PC. I had this problem intermittently on my standard XT. On my office PC, a fast AT clone, I experienced no problems at all. This situation is discussed in the thread file, M100CO.THD in DL 9. The solution to running M100CO on a standard PC requires switching the transmission rate from the normal 19200 bps to 9600. On your PC in M100CO press F8 to reset to 9600 or start the program with the command, M100CO /9600. My M100 copy program now includes a prompt during the start-up routine to select whether you want to use 19200 or 9600 when communicating through the MOTORON port of the 2 drive interface. Only the MOTORON side can be switched to the slower rate so make sure to connect your PC to this side. TDD2PC then automatically switches between 19200 when accessing the TDD and 9600 for the PC side. At 9600, much of the speed advantage of the PC with Booster-Link is lost but the total operation is still at least as fast as a TDD. A few other things are worth noting about M100CO. When using TDD2PC to copy disks you, of course, want the PC side to be completely reliable. When using a standard PC, it seems best to disable all of your terminate-and-stay-resident( TSR) utilities on the PC since some of these seem to cause M100CO to abort at unpredictable times. If you are using a single drive system, be sure to include a copy of COMMAND.COM on your M100CO PC disk since M100CO needs it during operation. This takes up 23K that could otherwise be used to store M100 files. The PC disk does not, though, have to be formatted as a system disk (i.e., with the 2 hidden DOS files). If you have a multiple drive PC system and your AUTOEXEC.BAT file includes a PATH to the directory on another drive with COMMAND.COM in it (such as a hard drive C:), you won't need to have the file on your M100CO disks. If you run M100CO from a drive with COMMAND.COM and then press F9 in M100CO on the PC, you can switch to another drive or directory. In this way you would not need either COMMAND.COM or M100CO.EXE on the target disk which would give you maximum space for M100 files. M100CO uses 2 temporary files on the PC disk, PDD_DIR.DAT and PDD_DIR.BAK. In the latest version of TDD2PC I have included a trap to insure that these files, as well as COMMAND.COM and M100CO.EXE itself, do not interfere when TDD2PC kills the files on the PC target disk. When starting M100CO on the PC, make sure that your 2-drive interface is switched to the PC side. M100CO looks for a complete connection and reports an error if none is found. Once the program starts, you can switch off the connection. I built my interface with a manual switch in parallel to the line to the M100 cassette port, so it's easy to switch to either drive in the manual mode without having to type MOTORON/MOTOROFF. In MS-DOS, most characters other than letters and numbers are illegal in file names. Because it makes no adjustments to your M100 file names, M100CO will fail if you try to save a M100 file which includes such characters. Booster- Link automatically replaces these special characters with a "-" character. I'm not sure how much of a problem this really is, so I haven't included the feature in TDD2PC. The only other problem I found with M100Co occurs when you try to overwrite an existing file on the PC using the POWR-DOS MAXRAMC calls as TDD2PC does. If you do this, the file seems to be appended to the PC file with the same name and is not overwritten. I have modified TDD2PC so that any time it copies a file to the PC where a file of the same name exists, the existing file on the target disk is deleted first.