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Model 4 TRS-DOS 6 (or LS-DOS) Basic - graphics and sound


New Member
Nov 22, 2021
Rio de Janeiro, Brazil
Hello to all. I'm an old TRS-80 Mod. I/III user, and I'm used to work with NEWDOS, including BASIC programming (note: I currently work with an emulator, I don't have here with me a real TRS-80 working, unfortunately). Recently, I decided to start exploring the Model 4 mode, with the 80-column video (and this is an entirely "new world" for me), so I started to work with TRS-DOS 6 and LS-DOS. But I'm experiencing a large "learning gap" in dealing with the BASIC provided by these operating systems. Mainly, I have noticed these differences (comparing with Model I/III running with NEWDOS):

1) Low-res graphics: it seems that Model 4 Basic (in TRS-DOS 6 or LS-DOS) doesn't have any specific commands to put low-res graphic points in the screen, like the old SET/RESETs. I know that the emulator I use (Matthew Reed's) provide high-res emulation with the Micro-Labs card and I already tested it (and it works nicely), but I was wondering if there were an easy and simple way to do just low-res graphics in BASIC in the 80-column mode. Without the SET/RESET commands, I'm limited to work just with CHR$ or POKE using the graphic block characters.

2) Sound: in the old Basic Level II or with NEWDOS Disk Basic, we had to use machine language routines to get sound. I saw that Model 4 Basic already have a proper SOUND command, but it is VERY limited. So, I'd like to know if there is any way to get "good" and more varied sound in BASIC programming in the Model 4, without using the SOUND command. Do we have to use a machine language routine, or can we get good results with the OUT command? Anybody here, by chance, would know of a good reference about making sound in Model 4 Basic?

I've got already some manuals from the Internet, mainly about TRS-DOS 6 and LS-DOS, but I couldn't find until now a good (deeper/more thorough) reference in BASIC programming in the Model 4 with 80-column video. If anybody could indicate me a good source of information for that, I'd be thankful. Based on the lack of good documentation about this subject available in the net, it seems to me that Model 4 was more used to run profissional software than to domestic BASIC programmers... am I right about that?

Thanks for your help.


Veteran Member
May 9, 2011
Upper Triassic
I would like to say that at some point I remember seeing in a magazine article an extension to restore the SET/RESET/POINT commands to Model 4 BASIC, but a casual Google failed to find any evidence so it's very possible it's just a case of tech deja vu. A known downside of trying to implement low-res graphics on the 4 is its 10-line tall character cells with otherwise unchanged graphics characters means that every third row of "pixels" is only half the height of the other two.

It is definitely not your imagination that the Model 4 was more strictly "business focused" than its predecessors.