LINEFD.INF Copyright Tony B. Anderson, All Rights Reserved One of the problems in the Tandy line of computers, especially the portables, the Model 100 family, is that in stock mode, the computer does not send a linefeed character to the printer, after sending a carriage return. This is based on the fact that the Tandy printer line automatically adds a linefeed character to any incoming carriage return - so it was not necessary to send it from the computer. On many printers, this is not a problem, since the printer contains a switch, either hardware or software, which can be set to add the linefeed to an incoming carriage return, thus advancing the paper at the end of each printed line. Many Tandy printers do not have this switch, the function is included as part of the printer control software. Problem is, many portable users, who may need to use any available printer, cannot reconfigure such printers to suit their needs easily, or may need to use printers that are already configured for other systems, like at work, or at a nearby Radio Shack store, or at conventions, sales, swap-meets or computer faires. Another problem developed among those users who happened to own both the Tandy portable and an MS-DOS computer, which DOES send the linefeed after the carriage return. There was no easy way to disable the LF-after-CR in the MS-DOS machine, so the printer could be configured to work with both computers without having to install a linefeed patch in the portable. Early in the life of the Tandy portables, the printer linefeed patch was developed, which used the system hook table to reroute the printer output routine, and add a linefeed to any carriage return that passed through the routine. In order to make such a routine "resident", and virtually invisible, it had to be installed in the function key table area, where it would not interfere with other machine language programs, or program operations. The principal objection to the linefeed patch program of course, was that it was lost at any time the computer suffered a cold-start, or the function key table was changed, since that is where the routine was stored. Nevertheless, the linefeed patch program was the only way to deal with the problem, since the linefeed could not be disabled from the PC/compatible, it had to be added at the Tandy portable. That gave rise to a second problem, by adding the linefeed patch, the portable was ALWAYS going to send it after a carriage return, and you had to be able to toggle it on or off, to accomodate the various printers you might be using, which means keeping a copy of the program in RAM, or easily available - which meant carrying a disk drive and utility disk, or a cassette recorder and utility cassette - along with the computer at all times, just in case. Another option, was storing the program in another bank - if you had installed a multi-bank board (in a Model 100), or in a RAMdisk, if you bought and attached one. As it turns out, there IS a way to disable linefeeds in an MS-DOS machine, which eliminates the whole problem at the source. While it won't do much to help in cases where you're using someone else's printer, in the case of a single user having different computers, and/or different printers, they can all be configured the same way, to send the carriage return only, and setting the printer switches to add the linefeed when it gets the carriage return. Tandy includes a 293-byte utility called LF.COM on it's distribution disks of MS-DOS (IBM, with PC-DOS, didn't!), which can be used to toggle the linefeed off or on, as needed. LF.COM can be added into the MS-DOS system configuration, via the CONFIG.SYS file, and the linefeed can be toggled with the MODE command: MODE LFOFF, or MODE LFON. The LF.COM utility appears to be available on Tandy's release of MS-DOS 3.2, as well as 3.3. Tandy's Customer Service in Fort Worth advises me that any user who needs it can get a copy by going to a store that carries the MS-DOS line of computers (preferrably a Tandy Computer Center) with a blank (formatted) disk, and asking that the dealer copy LF.COM onto their disk. (It helps to tell them Customer Service in Fort Worth told you to do so!) Once installed in the PC/compatible, and the printer switch set to automatically add the linefeed to incoming carriage returns, you can eliminate the linefeed patch program from the portable. But if you regularly use other people's printers, you'll still have to keep it handy. If you determine that you NEED the linefeed patch in the Tandy portable, then for the Model 100/102 see LFUTL.DES and LFUTL.PW1 in Library 7, or LFEED.200 in Library 10. Enjoy.