Congrats! The T3100 was my first ever vintage Toshiba portable, it's an awesome little machine.

1. As far as I know, there are no 720K floppy images of DOS 6.22, but I could be wrong. It can be manually installed, but I wouldn't be able to provide the exact steps off the top of my head as my T3100 came with DOS 5.0 on it and I'm content leaving that as-is because of its smaller drive space footprint. I know at the very least it would involve reformatting some of your blank floppy disks as 720K (You'd have to cover the HD hole with masking or electrical tape to do that) and manually copying files off the DOS install disks onto them, as well as creating a 720K 6.22 boot disk with FDISK and FORMAT on it to partition the hard drive and make it bootable.

2. The T3100 doesn't need a park command. The built-in hard drive automatically parks after five seconds of inactivity. Just make sure the "Left Disk" light isn't lit, and you should be good to turn it off. Beyond that, it can be treated just like any other drive. Be aware though, depending on how long it's been siting unused, one thing you MIGHT need to do before partitioning the drive is perform a low-level format. This was a common routine maintenance task that sometimes needed to be done to early hard drives from before the introduction of IDE, as gradually over time the platters on pre-IDE drives can literally begin to lose their ability to hold a magnetic charge. Low-level formatting a drive will write over every single sector on the entire drive, and basically "refresh" them so they can be used again. This is also a good way to permanently erase any personal data that may still be on the drive, depending on where the computer originally came from. This is not something the regular DOS FORMAT command does, you need a special program compatible with the installed model of hard drive to do the low-level format. After that, you can then run FDISK and then a do regular FORMAT to prepare the drive for use. My answer to question #4 below has a link to a diagnostic disk that will allow you to do a low-level format.

3. I would not know the answer to this question off-hand since the oldest DOS game I've ever played is DOOM. One thing to keep in mind though, the T3100 has CGA graphics, but the internal screen is monochrome only, not even different shades of orange. It's either orange or black, so even if you can find CGA games that will run fine on that system, they likely may not look good on the internal screen. Luckily you can connect an external CGA monitor to it just fine. There's a keyboard command to switch between internal and external screens. I don't recall it off the top of my head, but the technical manual should have that info.

4. Cannot think of any demos, but for software I'd recommend you grab the Toshiba diagnostics disk image and write it to a 720K-formatted floppy using Rawrite or WinImage. It can be downloaded at FOUND! - Toshiba CE Diagnostics Disks. This'll let you run various diagnostics on the system to make sure everything is working properly. It'll also let you low-level format the hard drive, which I'd definitely recommend you do before trying to install DOS. If after the POST "Error in CMOS" screen pressing F1 doesn't take you into the CMOS setup, then you can also use this disk to get into the setup and change the settings if needed.

5. BIOS battery can be replaced. Although it is possible to purchase a compatible replacement battery, the connector on the end of the new battery wiring will be different, so you'll have to cut the connector off both batteries then wire the old connector to the new battery. Be aware, the T3100 is A PAIN to open and work inside. The wiring connecting the screen to the motherboard is very short and permanently attached, there are no connectors that can be unhooked. The best you can do after unscrewing the case is lift the top up like the hood of a car at most 45 degrees, then you'll have to use something to prop it up so you can have both hands free. Then, when you go to put it back together, you need to make absolutely sure the little spring-loaded plunger sticking up from the motherboard hooks correctly back into the screen hinge (Open the screen HALFWAY before you fold the top of the case back down, then close the screen once the top is all the way down). That plunger is the switch that turns the screen on and off when you fold it open or closed, and is easy to break if you don't get it hooked back into the hinge correctly. If it breaks then the screen will stay off when you open it, essentially rendering the system useless.

As for the screen, columns of pixels that are either dead or stay on are unfortunately common on the early Toshiba plasma-screen portables, my own T3100 has a line running down the center that is always on. I do not know of any easy way to fix this, as doing such is getting outside my area of expertise.

Some other tips:

-Make sure the "A/B/PRT" switch on the left side is set to "PRT", this way the internal floppy drive will be drive A: and the printer port will work normally. The other two settings are for use only when you have an external 5.25in floppy drive connected to the parallel port, and are used to tell the system which drive letter the external floppy drive should use. If you don't have the external floppy drive for the T3100, then there's no need to change it from the PRT setting.

-By default, all six of the DIP switches on the back below the power plug should be off (Down). The only one you might potentially need to change is switch #4, which changes the printer port to bi-directional...this is good if you want to connect a parallel-port Zip drive or use a parallel LapLink/Interlnk cable. Switch #5 can also be changed if you absolutely want to, all it'll do is change the on-screen text between standard and bold print...really down to personal preference (I personally find it easier to read in standard mode).

-Don't leave the screen on a static image for too long. Plasma screens burn in VERY easily. After installing DOS, it might be a good idea to look for a TSR screen saver or screen blanker that automatically kicks in after a few minutes of inactivity...or just close the screen when you step away from it to turn it off.

-If you are absolutely curious...yes, it will run Windows. I'd recommend no higher than Windows 2.03, but if you're feeling adventurous it WILL run Windows 3.0 (But not 3.1). It's a very tight squeeze on a 10MB hard drive though, and you have to use a hex editor on the "Olivetti" video driver files to get 640x400 resolution working correctly, otherwise you're limited to standard CGA resolution.

I agree to what torindkflt said. 720K floppies were a common media for DOS 5 (360K also).
MS-DOS 6.x is more from the 1.44MB days, but also got 1.2MB releases for a while.
I *think* it was possible to send a coupon (from the DOS package) to MS, for which you got 360K floppies in return.
No idea, if it was also possible to order 720K floppy disks. Also, using 1.44MB floppies in 720K mode is hit and miss.
It may work for you, but problems may arise soon if you're going to use different floppy drives along with such disks.

torindkflt wrote:

Congrats! The T3100 was my first ever vintage Toshiba portable, it's an awesome little machine.

Thanks for the answers Torindkflt and Jo22!

The orange glass plasma screen is charming, I had hopes of an oxidized connector that caused the missing screen lines but they are probably permanent as you said. The service manual shows several exploded views of the laptop, I think I will at least blow it out and remove the old CMOS battery for now. I will be extra careful to treat the screen on/off plunger connector with care.

For file management, I think a bootable DOS 6.22 floppy will be my first step to see if it would be any better than what is on the machine currently. I can remove the old user's Lotus 1-2-3 and other files by hand. The Toshiba test program was still on the hard drive, and all tests (besides hard drive tests) pass. I have an idea to get a parallel port Laplink cable and hook it up to one of my 386's to move files and games around. If anything, my favorite text only game, Druglord, should work a-okay.

This early model makes me want to find the VGA/386 "e" version that can run games like Wolfenstein 3-D and some of the Taito arcade conversions. I'll see what I can make it do as-is, it was well worth picking up, even though the cashier at the recycling center asked me "I don't know why you would ever want THAT!" $15 well spent!

As far as I'm aware, the T3100e only has EGA and not VGA. If you want VGA in a similar form factor, you'd have to step up to either a T3100SX (Hard to find and notorious for bad caps on the internal power converter board), T3200SX or T5200, which are all 386-based systems (T3100e is still 286). Nice thing about the T3200SX and T5200 is that they both also have two ISA expansion slots, one 8 bit and the other 16 bit, so you can easily add a Sound Blaster or other sound card of choice. They also have larger keyboards with built-in numeric keypads, and slightly larger screens that support different shades of orange for better color simulation than the base T3100 or T3100e. The screens on the 386-based portables also seem less prone to the vertical line issue from my experience, as none of the ones in my collection have that problem.

Thanks for listing a few other model numbers that have these orange gas-plasma displays; they have been helpful as I look around ebay for a later, more powerful model. Were these a Toshiba only display type, or did other manufacturers use the technology too? Is there a specific model number that is common and fairly stable? The 5200 you mentioned seems like it would be ideal since I can easily add a Soundblaster ISA card for gaming. Now, to find one under $100!

A few other brands also made gas plasma portables during the mid-late 80s. I know the Compaq Portable III has an orange gas plasma screen, as did some of the early Grid portable computers. I've seen a handful of others while browsing eBay over the past few years, but those are the only two I can recall the brands of.

Here's a full list (to the best of my knowledge) of every model Toshiba made that has orange gas plasma displays:

-T2100*
-T3100
-J3100**
-T3100/20
-T3100e
-T3100SX
-T3200
-T3200SX
-T4400SX***
-T5100
-T5200***
-T5200/100***
-T6400SX***
-T6400DX***

*Be aware that Toshiba reused the T2100 model number twice for different computers in different countries. The one you'd want looks identical to the T3100, and to the best of my knowledge was only sold in Europe and Australia.

**Basically just a Japanese version of the T3200 from what I can tell.

***Also available with color or grayscale LCD screens, be aware of this when searching. Plasma-screen T4400 and T6400 systems are VERY hard to find, as these are 486 systems and by then plasma screens had already long been on their way out. You're more likely to find the LCD versions when searching auction sites. I've found only a single plasma-screen T6400 so far and it is in my collection, but the screen is defective and I'm hoping a capacitor replacement will fix it. I have yet to find a single working plasma-screen T4400 though.

There really doesn't seem to be any one model that stands out as more common than the rest on eBay. I admittedly haven't searched in quite a while, but I recall for a time quite regularly seeing the T3100(/20) pop up semi-often, as well as the T3200, T3200SX and T5200(/100). The rest of the models I listed above appear on eBay far less often, and I have yet to see a single J3100 or plasma-screen T4400 listed on there at all. Honestly though, it's down to random chance whether you'll find a good one or not, because even of the models that do appear more commonly, I've noticed that they tend to more often than not have problems with the screen.

I'd say perhaps the best model to aim for that you'd have a realistic chance of finding is a T5200/100. It's got a 20MHz 386, 2MB RAM (Maximum of 8MB) and a 100MB hard drive. The screen is also detachable for when you have an external VGA monitor connected. It even has a combination lock to lock the screen closed when you're carrying it. 🤣 Unfortunately, it's gonna be unlikely you'll find one for under $100, especially on eBay. Even if the sale price is below $100, the shipping weight would more than likely push the total cost up over that amount, especially if you're importing it from Europe (That's where most of the Toshiba portables in my collection have come from).

If you have a dos boot disk your 1/2 way to installing the OS anyway.
DOS installer doesn't look at hardware at all, so from your bootdisk format the drive with /s and the hard drive is now bootable.
You can now copy files from another DOS install over by disk, will take a few back and forth trips but you can even leave off any files you know you wont need.
(memmaker for example)

Although I know round the 386 and earlier most people prefer earlier versions of DOS as early CPU's cant take advantage of 6.22's "new features" and takes less disk space

Something else to be aware of when you take it apart to clean it...the eject button for the floppy drive is not physically attached to the drive, so it WILL fall out if you remove the drive sled. This by itself isn't an issue...it's getting the button put back in place and having it stay there while you put it back together than can be very frustrating. If you have a pair of locking forceps or spring-loaded tweezers, you can use them to clamp onto the button from outside the case and hold it in place while you drop the drive sled back into the case. Once the drive sled is in and screwed down, you won't have to worry about the button falling out again.

Thanks for the floppy tip! I made some progress with it last night, getting it to (1) read a 720K formatted floppy and (2) start two games from the hard drive; the games being Arknoid and Druglord (the text adventure). I was surprised at how speedy it seems with only a 8Mhz 286. I also tried to load Topbench to see the CPU/memory speed but was let down by read errors from the floppy. I hope it needs a good cleaning and it will be good again, alcohol on a q-tip got a lot of dark gray dust from the read/write head. I am hooked on the look and speed of the gas-plasma. I could not see ghosting that I am used to with color laptop LCDs from the time period. Bubble Bobble, Sky Shark, and Prince of Persia would probably run just fine on it, those will be next once I get the floppy drive more reliable.

DOS 3.2 is a bit of a pain; deltree does not exist, so I am struggling to remove directories. I also miss the editor for text files, mem, etc. I thought I might get away with a DOS 6.22 floppy and /s; good to know we had the same ideas!

Best of luck with your work on this one, ifkz!

ifkz wrote:

DOS 3.2 is a bit of a pain; deltree does not exist, so I am struggling to remove directories. I also miss the editor for text files, mem, etc. I thought I might get away with a DOS 6.22 floppy and /s; good to know we had the same ideas!

I leaned heavily on Xtree Gold prior to some of the more modern features of MS-DOS 5+. I am sure that you will most likely push MS-DOS 6.22 to that system once you get your floppies ready to go, but there are alternatives available if you would like to keep the system feeling a little bit older while also gaining some functionality.

torindkflt wrote on 2017-04-17, 03:50:

-If you are absolutely curious...yes, it will run Windows. I'd recommend no higher than Windows 2.03, but if you're feeling adventurous it WILL run Windows 3.0 (But not 3.1). It's a very tight squeeze on a 10MB hard drive though, and you have to use a hex editor on the "Olivetti" video driver files to get 640x400 resolution working correctly, otherwise you're limited to standard CGA resolution.

I know this is a very old topic.
As it happens - I have a Toshiba T3100e , which has the same CGA screen as the T3100.
I'd love to know, if someone has documented the steps of what exactly needs to be "patched" via HexEditing the Olivetti and AT&T 6300 driver ?
Since the 3100e is a faster 80286-16 , running Windows 3.0 makes so much more sense - AND - there's alot more software that is potentially compatible.

Thanks