The SHELL, FILES and FCBS settings belong to CONFIG.SYS, not AUTOEXEC.BAT. ;)

That's pretty neat, I didn't realise the origins of dual monitor went back as far as that. Another idea for a game that would work well on that setup would be Battleships; where each players grid shows on a separate monitor (facing away from each other) and the keyboard is passed between them.

I'm pretty sure AutoCAD supports dual displays like this, with the command line on the mono chrome monitor and the drawing on the color screen. There's a reference to it in the help files for R11.

The wobble on the mono crt is probably the two monitors' yoke coils interfering... Space the two farther apart and it'll probably decrease. Edit: ahh I see you did later in the video :)

It would be cool if The 8-Bit Guy added dual monitor support for Planet X3 even if it’s just a monochrome status information screen it would be neat. Great video as usual!

5153 Recap video?

I'm not sure it will run on a 5150, but Borland's Turbo Debugger had support for dual monitors. It was a feature commonly used to debug Windows 3.x apps, with Turbo Debugger running on the monochrome screen and the Windows GUI on the other.

Great video... Absolutely love your stuff. Lotus 1-2-3 for productivity and Borland Turbo Debugger for development are excellent candidates for a dual screen setup on a 5150. Very easy to setup. Just used it with my 5150 and it's really awesome. Really adds another dimension to using this hardware.

Just my tips, hopefully I don't bore you or anyone (khmmm, too much ...): You don't need to change data segment register (DS) to 0xB000 and 0xB800. Since the segmentation model, you can just set 0xB000, and write offset 0 and 0x8000 and it will the same result to write offset 0 at segment 0xB000 and offset 0 at segment 0xB800 (yeah, 0x800 part in segment vs 0x8000 in segment, as segment is a 16 byte unit of address at least in real mode on x86 ... what pre-286 CPUs had only). It would allow you to avoid always changing a segment register which would slow your app down. However. I would use ES not DS, since a real app need its data segment to, pointed by DS, so it's better to use ES for addressing the screen as the segment register. Also some handy opcodes would use ES by default as target segment anyway, like movsb and stosb ... So in some cases it even helps further. Surely, code optimization in assembly "by hand" is a tricky business anyway, I used to count clock cycles needed for a given opcode, to figure out what is faster and what is not, on PC, and before (like on Commodore 64) too.

That's amazingly cool to see in action. It's fantastic what these are capable of with some clever thinking (and a fair few cards, of course!).

I had a 5150 as a kid and took out the CGA card and put it in a 286 with a build in Hercules card. I had both monitors setup and after a lot of tinkering found the mode command and switched between them for games and stuff. I could choose low resolution and bad colors or sharp resolution but orange. what a choice!

I like your videos- interesting variety of hardware and actually using stuff

Used it for turbopascal , the textmode was much more better on MDA/hercules. So config the turbo on monocrom and let him put out the result on CGA , or VGA hires

This is such high quality content! Big fan of the channel

Great video AkBkukU! Really like this channel P.S. I can't figure out why people dislike your videos

Back in 1990ish, we used to use this dual monitor support support in all sorts of PCs, as the mono cards and monitors were virtually being given away. We used Turbo C and Turbo Pascal to write some TSRs that would monitor PC specs and we could hotkey out of most applications to a mono DOS window. We also wrote a quasi-networked bouncing ball program that would allow each monitor (two per PC) to be custom positioned in a virtual grid corresponding to the physical layout of the monitors in a 2x2 or 2x3 orientation. After moving to OS/2, I used to keep a handful of mono cards and monitors for dual heading my development systems, but by the time I started using Linux, it was just easier to set up obsolete computers running terminal. LOL, I used to have upwards of a dozen monitors on my desk so I could monitor our telephony systems live. This has led to the present day where I run two 49" 4K television as a monitor so I can stack up dozens of term and web browser windows. I am a sick, sick man. ;-)

I love these old characters displays. Nice videos!

Awesome idea to directly write into the memory addresses of both cards at once :)

Thanks. Showing this brings back memories.

Subscribed, this is just the sort of thing I'm into.

you sir, are completely nuts - in a good way

Cool video. I have run across talk about the dual monitor setup but never bothered with it for the same reasons with my IBM XT

Love that warning label on the power supply. Danger zone!

There are (original) 286 and 386 upgrade cards for the PC, if you *really* wanted to get into the rabbit hole :) (ISA card with a ribbon cable going to the 8088 socket) Still pretty legit, even if you couldn't get the programs working!

This is really interesting my friend. Pretty cool

We used Autocad at work back in the ‘80s with dual monitors on IBM XTs and ATs. Initially we used proprietary colour cards (BNW) for the graphics window but later simply extended VGA. The only setting in Autocad to trigger this mode was whether the graphics screen would have a command line. If you set it to “no” it simply directed console output to the monochrome address, or at least to the IBM-standard display address not specified for the graphics window. The main usefulness of this was that more lines of command history were available and you get a tiny bit more drawing area.

You make me want to learn Assembler and C just to write weird software on early PCs. Just seems more exciting than more modern stuff.

Nice, I'm glad you're like one of the few I hit the bell icon for! I wonder if you and Dave from the 8-Bit Guy could work together and add dual monitor support for his in development DOS game.

Nice, we used that Mano Digital Logic book in college, it's excellent.

Awesome video! That setup does also work with MGA cards, you know. Hercules even cared about it and added a "half" mode for its graphics mode, to avoid that the video memory would overlap with CGA. :)

awesome vid! like always!

It is very cool, though I have to say it's more of a happy accident because of the architecture then actually being an intended feature. Probably why there is so little that took advantage of it, though I do like the idea of using the mono card for debugging info while running. That is a clever way of getting the data out without interfering with the game.

Asteroids on this dual setup (dual 5153s) would be cool... Move to the edges of the screen and depending on what direction you are facing, come back on the opposite monitor.

the video I've been waiting for

As kids, my friend and I wanted to make a flight sim program like Gunship where the pilot would have one monitor and the gunner would have another monitor. The issue is that you get to the point where you need more input (joysticks, keyboard, etc) than is worth your while.... then dual computer gaming started to come out (modem, ipx\spx...etc).

I just bought that Graphics Programming in C book! I have a bunch of other graphics-related programming books for early IBM PCs - there were so many of them.

These machines are so beautiful. Image a modernized internals, and gpt-4 and next versions, with their text interface...

Takes me back: the favoured way to debug Windows programs was to use a VGA card for Windows 2.x and an MDA adapter for CodeView. That was about 1990.

I wish I had an IBM Professional Graphics System to send you! Those were super cool. It was an 8086 computer with 256k of RAM, that occupied 2 ISA slots in a 5150 and had a special monitor connector for its own monitor. It could do (for the time) incredible full color graphics, but it cost a fortune. The display modes were eventually folded in to the abilities of XGA onward but are generally not used by any applications or what-have-you. If you get the opportunity to get one, please jump on it! (And, obviously do a video on it :) )

This is rad. I wonder what will happen if I put two VGA cards in my 286? .... probably a small fire.

I remember seeing MDA secondary monitor mentioned ONCE back in the 90s. It was on a shareware "mahjong" game. It would display the graphical playfield on the color monitor, and use an MDA display to show what tiles were still in play. SO EXCITING. That is the only time I ever saw this capability mentioned before today. The color screen in this case was PROBABLY VGA, but it has been years since I saw the shovelware CD that came on. No idea where it disappeared to.

TIP: You can fake 160x50 "pixel" graphics on the MDA. A full screenfull of text is 2000 bytes (80*25 * 2 bytes per character, 1 character 1 attribute), but the MDA itself has 4 KB of memory. Normally this is used for scrolling -- a register in the MDA holds a start address where the screen begins displaying from, and you can scroll without copying 2000 bytes around by manipulating this register. Another register controls the number of scanlines per character. If you set this to half the usual, you get 50 rows of 80 characters, with only the top half of each character displayed, taking 4000 bytes to show the whole screen. Set each character to either a space, a left-half-block, a right-half-block or a full block, and you can make 2 blocks per character cell, for a total "graphics" resolution of 160x50, with 3 possible "colors" for each "pixel" -- black, dim, and bright. Alternately you can make 80x50 nearly square "pixels" with no MDA hacks, simply by using to-half-block and bottom-half-block characters. I've experimented with the possibility of getting more "pixels" by racing the beam, but the PC simply isn't fast enough. That is, write characters that have roughly the pixels I want in the next scanline, then change them up during hblank. Alas, the 8088, ISA and MDA aren't fast enough. With a REP STOS instruction and all interrupts but DRAM refresh disabled, I managed to write a whopping FOUR characters in an hblank, which simply isn't enough to pull off a believable pixel mode. Some additional hackery with MDA registers may be possible though. (Just be sure never to modify the "output voltage" bit, which is a vestige left over from the CGA design -- this can permanently damage the monochrome monitor.)

Interesting video, thanks. Beat you to this though, my first pc was an XT clone and I got both CGA/Herc cards. Had no money for monitors, so, with the help of an electronics whiz friend, cannibalized a text terminal for the hercules card, and used an old TV with an adapter to connect via RCA jacks for the CGA. So I could run Flight Simulator on the CGA, and/or do other/text work on the mono one. Yup, not at the same time, and used same mode commands as you found. This was around 1984, I think, so a while back, and yes, I was 33 at the time... :) RichE San Diego, CA

Dual screen back in those days was really nice for debugging. You could run you program and have the debugger on your monochrome screen.

The classic use for this back in the day was to debug a program. If you ran the program on CGA the debug commands and display could go to the MDA monitor (since there were no windows back then). Most debuggers supported this including "debug" that came with DOS.

Later era, but I've been hearing Command & Conquer uses the same method to show debug info. Apparently it still does in the release version because they assumed endusers won't have a setup like that. Might be worth investigating.

If I remember correctly, many early PC CAD programs had you edit the data on the MDA and show the resultant object's wire-frame representation on the CGA's 640*200 mode.

ha ha I remember doing similar when I used to write computer games back in the 80s as I had to write for both screen types using Apricot F1 systems ... they actually offered me 2 of the computers back then for £80 each which was a good price ... lol i regret not buying there worth a lot more now there very rare but back then i was living with my parent so it was not a good idea as the last computer I had my step father took a hammer to the old computer i did not talk to them for a long time .. it was a intertec superbrain one of only a few made with a 3D graphics card yes ... i only ever seen one which I had which was a prototype and my step father took a hammer too it ... I cried!

great video :)

Want to do something just because it's possible? I can respect that. I listen mp3 on my vampirized amiga 600 because now it's possible.

Not sure if anyone told you yet but the "wobble" you have on the monochrome is because it's not shielded well enough and is picking up the magnetic pulses from the CGA monitor. Place them further apart or a grounded aluminum shield between them to help eliminate it.

I can't even setup a dual monitor on a modern pc. Then you do this. Excuse me what the heck.

If they still peak your interests I have a dual monitor, color and green, dual case, 2 floppies in one and 2 hard drives in the other with this giant patch cable, setup with boxes of games and hardware. Some hardware was even prototype stuff. It would be a vehicle full of stuff.

To fix the wobble, either put some space between the monitors, or stick a sheet of metal, like an ATX side panel, between the monitors to isolate the magnetic coils of the two monitors from each other. I used to run multi-monitor with CRTs before I replaced them all with LCDs, and had to deal with this all the time.

I know I'm 5 years too late, but it's really common for one monitor's magnetic field to interfere with another's sitting nearby. That's probably where the wobble is coming from.

I'd love to see your game!

"oh i didnt see you see there, i was just setting up my ibm 5150"

Fun Fact: my 2013 Business laptop actually can be bought with FreeDOS installed. and it does work by default. I don't know how well it can run since i was just looking through directories, but it seemed snippy running over a USB drive that is WAYYY too big for a DOS machine (It was 8GB). but then again, a 240GB SSD is too much for DOS anyhow. If you want to know more about the laptop: The laptop is a HP EliteBook 840 G1 with an Intel i7-4600u and 8GB of ram, integrated GFX, 240GB Samsung drive pre-equipped from the factory, all the fancy stuff. The main reason i bought it was because i could buy a separate dock that uses an HP proprietary port to almost double the ports on the machine. Turns out my mom has a newer version of the laptop for her work and they gave her a dock and I'm using her dock because she gave it to me. also got my hands on another 2 power supplies after the one that came with mine wasn't outputting the correct power and the laptop was not charging correctly. She had like 3 or 4 so i grabbed another one for the dock so i don't have to worry about plugging in power every time. Sorry this might have been a useless waffle, OOPS

The HGC also uses a 6845 CRTC chip. A major difference between the MDA and HGC was the amount of video RAM on board, which allowed the HGC to do hires graphics modes.

It is really color/graphics. You could display color or graphics. Displaying both at the same time was limited. Turbo debugger used two monitors at the same time. In color monitor you saw your program running, in monochrome you saw the debugger. The Hercules really had nothing to do with CGA. It was basically MDA with 64 KB memory and graphics mode (2 pages 720x348, though you could use only one page in two monitor systems). There was no support in BIOS for it so everything had to be done with direct manipulation with hardware. I think it is pretty cool that such a feature that has become common only recently was actually available on PC from the beginning.

This is really cool, I thought the DEC Rainbow 100 was the only machine capable of dual monitor at that kind of time. Autodesk AutoCAD 2.6 for MS-DOS on the Rainbow allows dual monitor support if I remember correctly, not sure if the IBM PC version ever did. Under CP/M I've seen the GSX Draw command draw colour graphics on the Rainbow's VR241 colour monitor while the VR201 monochrome display still shows the fully functional CP/M command prompt. I don't know of anything else on the Rainbow that supports it but perhaps since the dual monitor option was only ever documented and never officially supported by DEC (it requires a custom made cable since an official one was never produced), AutoCAD on the IBM PC may have had some sort of dual head option in one of it's versions as well at some point.

There is always the waybackmachine to look at old web pages that do not excist anymore ;)

I would totally buy that clone of battle zone for my Tandy 1000 EX.

i think this is the first time ive ever witnessed a cap blow up in the middle of a youtube video

That's interesting how you can write to both. I can see how this would be under supported though. This sounds like a very cost prohibited setup for a lot of end users back in the day

not seen x86 assembly in years I spent a lot of time in Z80 :D

I think that it was Mechwarrior I noticed using the monochrome display for debug information, with the VGA/EGA(?) display doing graphics; but it's been a very long time since I've played that game on a machine with multiple display adaptors and monitors (Hercules + M7 cards)

I didn't even know that PCs could support multiple monitors as far as 1981. I remember it being in Win98. I have read about Macs supporting multiple monitors in 1986 with the Macintosh II desktop.

I seem to recall people using two computers telnetting to the host computer whilst using a TSR application(like xtree? or norton commander) for a sort of dual screen effect. this way you could read a document whilst still being able to access the filesystem from the other computer. Not sure if we were on XT/ATs by that stage.

Where do you get that CF card adapter. Would be really handy for my IBM 5150 I recently finnished restoring. The person I got mine off said that she use to use a program where you would enter in data on the mono monitor & it would display the graphs on the colour monitor. Sadly she binned all the software long ago So I got all the hardware - the MDA card & monitor & the expansion unit communication cable. When I first saw it I though the expansion unit was a seconed IBM 5150.

A good example of an application that makes use of dual monitor setup is AutoCAD. You can probably find a copy of an early DOS version somewhere in the Internet.

Borland stuff might work. Turbo Pascal was probably capable to handle editor on monochrome and output on the colour one.

Dual monitors for DOS are epic for software debugging.

Well, RHIDE was part of the DJGPP environment, which was all about being able to use 32-bits protected mode in DOS using the GO32 extender (just like Watcom did with DOS/4G). Building a 16 bit version wouldn't even be possible. GWBASIC may also be able to write to both screens in a simple way. SCREEN will allow you to choose one display or another, although it will probably clear the screen each time. However, you could always write directly to the screen with a DEF SEG=&HB800 or B000 followed by POKES just like your assembly code does.

Did you try lotus 1-2-3? Supposedly you can do spreadsheets on the mono and graphs on the CGA.

yea, thats cool. That "mode ..." switching is not bad when your color monitor is a 21" on a EGA/VGA, which could be set to 132 x 60. Actually you should be able to do something similar but replace the MDA card with a Hercules (I think they use the same address), and set that up for hi-res text (100x33 or similar?). Anyway, I have done the same on an AtariST, Color TV & Mono Monitor :) gotta love those hires fonts on mono screens, the Herc had some really beautiful font available .. and I think there were some mods/enhancements you could do to the card to get some higher resolutions, or higher res text mods (cant remember exactly, it was 35+ years ago I was playing around with them) ..

I think Turbo Pascal or Borland Pascal (can't recall the version) supported running the debugger on a mono monitor.

10:24 Wait, - what? You were trying to install a program that was 177 MB on an IBM PC XT? Going completely from memory, my best guess is that the hard drives of the time came in 5 MB, 10 MB, and possibly 20 MB. That you were trying to install a program that is a factor of ten over the size of those drives should have been a warning from the start.

The 1990s flight sim "Back to Baghdad" let you use an 8-bit mono card and monitor to display the radar scope of the (simulated) F16 you pilot in the game.

How about double dos? I recall using it to run two different applications and switch between them in the mid 80s. Perhaps you can run an application on each monitor and switch between them?

If the caps are in that state, I would be very reluctant in continuing to use the the monitor before completely replacing the electrolytics. Ive seen and repaired many monitors that have failed from continued use with old leaky caps (electrically and physically) that cause other problems taking out other more expensive and sometimes rare components like switching transistors etc.

shell, files and fcbs are for config.sys

I think Lotus 2.x has the capability of displaying a spreadsheet in one monitor and its graph in the other one (given the one which is displaying the graph is not mda or sth like that. It should not support graphical capabilities).

I use the video out on the CGA card on my 5155 to my TV. The inbuild monochrome monitor still shows whatever is on the screen, even if it is a game in CGA mode (albeit in mono). It would be interesting to see if it can output out of the CGA port at the same time as well, for three screens.

The files, fcbs and shell lines must be in the config.sys file, not autoexec.bat.

Turbo Debugger was capable of using a Mono monitor for realtime debugging with the application running on the main display.

FUN FACT, IBM HAD A SCALE DIVISION, CALLED DAYTON. ALSO CASH REGISTERS ASWELL

Im am currently watching this on a dual monitor system.... from 2017-current (upgrades and all) :P

you can try making also a demo for the monochrome card because there aren't any out there

Im very certain early versions of AutoCAD would run duel screens but I think it required a Hercules card, not MDA

Wow.... this channel slowly becomes main source of IBM goodness on YT... just don't decorate them with wood.

I run 1-2-3 on my 5150 with spresdsheet on MDA+5151 and graphs on CGA+5153. Still looking for an early version of AutoCAD that would run on my setup, because I'm sure dual monitor use was a standard there. I even bought an 8087 for that purpose!

The monochrome monitor is wobbling because of the colour screens power supply - Edit: I see you moved them apart and cured the wobble.

I have done a VGA CGA MDA tripple IBM XT screen setup, the setup was cable hell, all factory default cable length was evil short for all ergonomics screen furniturings :-( had better succsess doing this tripple xt screen setup with an A2000, A2088xt setup with and fourth screen in PAL mastercontrol OS We actually had a small classroom setuped with original IBM XT dual screens for GW-Basic Classes in 1991

I wonder if you could modify Windows 3.11 or similar to run with 2 monitors. It would be cool to see windows with that much real estate. of course you're limited by the color and monochrome displays, but it would be so cool to have a dual monitor windows setup using all original components.

A program that works like linux screen would be useful, allow you to direct inputs wth a keyboard command to two programs running at the same time.

Turbo Pascal did use dual monitors for debugging. I'm not sure what versions supported it. I had to be version 6 or 7 maybe 5 too. I did this for a time, so I know it works.

CodeView and QuickBasic uses this setup for interactive debugging.

5:34 Could your problem be that putting the monitors side-by-side like that is causing interference? Could the magnets in one monitor be affecting the display of the other? Edit: 13:42 Good for you. You figured it out.

If you can get your hands on the CodeView debugger (part of Microsoft QuckC but also other compilers such as Visual Basic for DOS) you can run the debugger on one screen while the program you're debugging is running on the other screen. It worked really well and was much easier than using a single screen: if you wanted to use CodeView to debug a DOS program on a single screen, it would switch back and forth between the DOS screen and the QuickView screen and while you single-step, that gets pretty annoying.