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This won’t be a full on review and more of a briefer overview as I actually never did manage to restore my model II to working order before letting it go to someone that hopefully can but it is an interesting machine.


As you can tell by the above advertisement the Radio Shack TRS-80 Model II is a pure business machine, even more so then the earlier Model I. The Model II was released in 1979 and was squarely focused on the business world. The model II had either 32 or 64kb of RAM, a Z-80A CPU at 4mhz and used a different OS then the Model I (TRSDOS II) as well as CP/M, not that the original Model I was a hardcore gaming machine but the model II although more advanced was even less game friendly. I’m not going to go much farther into specifications since that can all be easily Googled so lets just go over the machine.


The computer itself is pretty heavy. This can mostly be attributed to the built in black and white CRT screen. The case itself is made of grey plastic. Its a fairly durable case overall but it does kind of feel cheap and you can cause cracks in it if your not careful. The power and reset switches are to the right of the monitor. The switches on my machines kind of felt a little loose and flimsy but I’m not sure if that’s a model II thing or was just my machine. They way the keyboard attaches is also rather odd-ball. instead of the cable coming off the keyboard its actually attached to the computer so its sort of backwards.

The other immediately noticed feature of the model II is the massive 8 inch floppy drive mounted next to the built in monitor. I’m sure there were other computers that used 8 inch drives but the model II is the only machine I’ve ever come across that uses one and may be the most common one to of used one. The floppies themselves held about 500kb of data which isn’t bad at all for 1979.

Here’s the monster of a drive.


And here is a floppy disk size comparison.


My machine gave a “boot error DC” that I never solved. I think it had to do with the floppy drive just not being set up or connected correctly but to be honest I never put to much effort into trying to solve this. apperently there are ways to add a 5 1/4 or even 3 1/2 drive but that begs the question of where/how would you mount them?


On the back of the machine we have ports to connect the optional disk expansion box which would give you the ability to add more Floppy drives or hard drive options. There’s a printer port and two serial ports as well as the AC power connector and a fuse.

speaking of the expansion box.


This is the very heavy expansion box. This one came with a second 8 inch floppy drive. This expansion box would be used to add more drives or hard drives. It has its own power supply built in and its own power switch.

Now will take a quick look inside the machine.


Most of the internal space is eaten up by the CRT tube as well as the 8 inch drive. The center board with what look like ISA slots (they are not) is how the various components interface with the TRS-80. The connected boards are separate floppy controllers and the CPU board which makes this machine interesting since its not made up of one integrated motherboard. I would of liked to pull each board and photograph it but I was a little pressed for time and the bar that hold these boards was pretty firmly screwed in and I just didn’t feel like dealing with it and possibly messing something up.

I did though take a short video of this machine powering up which sounds like a 747 powering up for lift off.

So that’s about all for the model II. Its a very interesting machine but squarely focused at the 1979 business market if you want to get into the TRS-80’s I’d suggest a model I or perhaps a model III/IV if you can find one.


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In this Odds & Ends I’m going to go over the venerable TRS-80 Model 100 a small portable computer. Also the much more successful relation of the LS-120 super drive the Iomega Zip drive and finally a number of gamepads from the king of PC gamepads in the 90’s, Gravis.

TRS-80 Model 100

Considered the worlds first laptop computer I came across my model 100 at a Goodwill and purchased it for a couple of dollars, about $3 I believe and to my surprise on hitting the power button the thing turned right on.



As you can see the model 100 is sort of like a giant calculator. These machines began to be sold back in 1983 and have anywhere from 8kb to 32kb of RAM. I believe mine had 24KB installed. Apparently these machines were very popular with news journalists and other “on the move” individuals. As I am primarily a gamer and this machine is pretty obviously not a gaming machine I don’t have to much to say about it but I did think it was kind of a neat little find. It has no internal mass storage capabilities so for saving anything permanently you would need to use an external cassette player of disk drive. The screen is a non backlit LCD and despite the age it displayed quite clear for me. I’m going to go out on a limb here and say that its probably only capable of text display. It is also powered by 4 AA batteries but also has a port for an external 9v dc power supply. I’ve read that it is very easy on batteries and can go for 16+ hours on batteries.


Here we have the back of the computer with most of our ports. We have a small reset button as well as a RS-232 serial port and printer port. The north American version like this one has a built in 300 baud modem which I believe that phone port may be for. Lastly a cassette port for a cassette player for storage.

Other then that I don’t have much to say about it. Its a neat little machine but doesn’t have much practical use I can find today at least not for myself. Apparently this machine has quite a following though

Iomega Zip drives

Ah, the Zip drive. The much more popular “floppy” storage alternative to the LS-120. The Zip drive’s initial version could store up to 100mb of data on a disk and eventually a 250mb and 750mb version was released. Unlike the LS-120, Zip drives cannot read or write to standard 1.44mb floppy disks but they do have a higher transfer rate to their disks then a floppy has to its own. I’ll admit the Zip drive has become indispensable to me lately as everything from DOS to windows 7 supports it. Although smaller in storage capability They are more convenient then burning CD’s. Its nice to be able to download a patch or file from your internet connected Windows 7 PC that may be a little to big or to many files for a standard 1.44mb floppy. Transfer it on a Zip disk and then easily transfer that file to you ancient 286, 386, 486 or whatever PC. With a cheap and advisable NEC V20 CPU upgrade the Zip DOS driver even works on 8088 based PC’s like the original IBM 5150 via a parallel port. I even believe Zip disks are Macintosh compatible (may require mac formatting or only certain models). I personally tend to stick with the 100MB models as the larger capacity models seem to be rarer and more prone to failure as well as not being fully backward compatible. Also 100mb tends to be more then enough storage capacity for my pre USB capable systems.I believe zip drive drivers are included with Windows XP and 7. At least I had no trouble connecting my external USB drive to my Win 7 machine. There are separate drivers for Windows 98 and DOS. I don’t generally link to drivers here but I can tell you they aren’t hard to find with a web search. you can try the Vogons driver database here and check under uncategorized or utilities for the relevant drivers. The DOS drivers should fit on a 1.44MB floppy and all you need to run is Guest.exe and it will assign a letter for your zip drive. You can set it to do this on boot though your .BAT file but I generally just have it in a file named “ZIP” on my hard drive and only use it when I want to use the Zip drive since the TSR does eat some DOS memory when active.

I’ll start off with the internal drive. The internal drives came in two flavors, IDE and SCSI though the SCSI version seems to be far more uncommon.



Here we actually have a 250mb model which is identical except for storage capacity and logo to the 100MB model. I’m using this particular drive since all my other internal drive are install in systems at the moment. The internal drives are the same 3 1/2 inch size as a standard 1.44MB drive so you can install them anywhere you would one of those. Like most this is an IDE version and connects to an IDE controller just like your standard hard drive or CD-ROM drive. Being IDE it also has a jumper for Master, Slave or Cable Select. Many BIOS’s from the mid 90’s up directly support Zip drives. The thing that I find slightly annoying is the use of a larger molex power connector used for larger devices such as hard drives as opposed to the smaller floppy power connector. Usually that means I have to dig out or buy a Molex splitter because I’ve already used up all my connectors on hard drive and CD drives.



Here we have the uncommon SCSI version of the internal zip drive. These were most likely intended mostly for Macintosh users. The front bezel is a little different and as you can see on the back it uses the smaller floppy drive style power connector as the 50 SCSI connector is larger then IDE. You also have jumpers to set device ID number and SCSI termination.

Now I’ll move on to the more common and cheaper external drives which happen to come in many flavors from USB and Firewire to SCSI and parallel and possibly others. These drives require and external power supply but other then that are identical in function. I tend to see these external drives fairly commonly at Goodwill’s and thrifts at a decent price. About $9.99 but sometimes under $5.


This is my USB external zip drive that I use with my Windows 7 machine. The see through blue plastic shell is kind of cheap looking and it kinda clashes with my black PC but it works like a charm and was as simple as plugging in the power and USB cable and then it just works.


Here is an assortment of older external parallel port and SCSI drives. On the far left is a Epson branded 100MB parallel port zip drive. The parallel port drives are very versatile and will pretty much work with any IBM PC or clone with a parallel port all the way back to the 8088 based models provided there CPU is upgrade with a NEC v20 chip. I believe this is because the V20 does contain some later coding that the 8088 lacks but which the Zip drive needs to function. As far as I know these are identical in function to the Iomega drives except for the branding and the color. I prefer the off white color of the Epson models as it looks much better with the off white case coloring of 1990’s and earlier PC’s that I generally use it with. The middle drive is a Iomega branded SCSI Zip drive. Finally on the far right is a 250mb model which uses a parallel port.


Here are the parallel port and SCSI port drives from the rear. The parallel port drive is pretty simple with a input and then a pass through for a printer or potentially any other parallel port device. The SCSI drive has a few switches though. One is to set termination either on or off. On a SCSI chain of devises you want a “terminator” device on the last connection in the chain or have the last device on the chain set as a terminator. It also has a switch to set the device number ID for the SCSI chain. The SCSI Zip device can only be configured as ID 5 or 6. Also take not that the Zip SCSI drive uses the same 25 pin SCSI connector found on many Macintosh’s. Your going to want a 68 pin adapter like this one if you want to use it on most later PC SCSI controller cards.


All in all I’m a fan of Zip drives and they’ve been a major convenience for me in transferring files. If your making a retro rig I do strongly suggest at least keeping a external model handy.

Gravis Gamepads

Back in the 1990’s Gravis was known for their Gravis Ultrasound sound cards for PC’s. Sound cards largely seen as superior in sound quality to the Creative Sound Blaster line but they also made a line of very successful PC game pads. Although their sound cards never became the de facto sound standard there game pads for the most part did. I have a few Id like to go over here. Keep in mind this is a evolving article so as I acquire more I’ll be sure to add them.


This I believe is the first model introduced labeled just the Gravis PC gamepad. I do believe there were a few minor variations. It has a standard D pad as well as a little joystick part that you can actually unscrew. This pad is very common and I see them at thrifts all the time though usually the joystick part is either missing or broken off. These make really nice DOS gamepads for games that support joysticks/gamepads. I like to use them for first persons shooters like Doom or Duke3d or platformers like Bio Menace. No drivers needed just plug it into your gameport either built in or on your sound card. As long as your game can be configured to use a gamepad it should work.


This is the Gravis Gamepad Pro which is also a fairly common gamepad. This pad is a little more modeled on console controllers and bears a resemblance to the playstation controller. The gameport connector on this model is a pass through so you can connect a second gamepad for two player gaming. Other then that its basically the same as the standard gamepad though it does sport a start and select button as well as four more buttons on the shoulders. I generally prefer this controller and this is what I generally use for games like Doom or Duke3d.


Here we have the Gravis Destroyer. In most ways this is kind of a step down from the Pro controller. I think its a little more comfortable to hold but it has less options. Less buttons including the lack of the start and select buttons, no joystick knob and the port connector is not a pass through so forget two player. It does sport a turbo button and LED that lights up green when activated which seems like a handy feature for shoot em ups. This controller does seem slightly less common “in the wild” and as the others is a breeze to use in DOS.


The Gravis Xterminator. To be honest I don’t know much about it since this is a digital gamepad and as far as I can tell does not work in DOS. Maybe it will with drivers but from my initial search I could not find drivers for DOS or its intended OS Windows 9x. This controller does sport a lot of buttons as well as a analog joystick. It also has a pass through connection to allow other gamepads to be connected which is nice. I’ll keep looking for drivers this controller and update this article once I find them.


Lastly I have a USB Gravis Gamepad Pro which is basically just a straight USB version of the standard gameport gamepad pro so in all areas besides the interface it is identical. This is a basic but excellent gamepad and since it uses standard windows joystick drivers it should be just plug n play for windows 95 and up. I frequently use this controller on my Windows 7 machine for arcade emulation and it makes a great and simple gamepad that you simply plug in and it works.

Gravis was a defining force in 90’s PC gamepads and I highly recommend at least the gamepad or preferably the gamepad pro for all your DOS game padding needs.


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