Microsoft BASIC-80 In Secret? VTech's PreBASIC 

Yes it is. I have one of these with a socketed ROM, easily dumped. The code is a patched over a copy of TRS-80 BASIC. Unused keywords are simply written over with nulls to disable them, then the code that they occupied can be reused for custom I/O support. It even adds a new keyword SOUND, which reuses the token for ERROR. Side-by-side comparison shows that most of the code is identical, and at the original addresses. It even still has the original TRS-80 SET/RESET graphics code at 0132. Whether it was copied from a Model I or Model III is somewhat hard to tell, but the code addresses for CSAVE and CLOAD are both above 3000. One interesting thing is that at 3CEC, in the address space that is used by the keyboard in a real TRS-80, is a complete set of long error messages. It seems like this had previously been hacked with a few other custom keywords that still have code addresses above 3000, but were disabled for the Pre-Computer. Perhaps it came from some unknown TRS-80 clone before being used in the Pre-Computer. But that is only half of the ROM. The other half is full of your usual toy computer math quiz type stuff.

I had a version of this computer that was localized for Germany when I was 11. It was called "Mister X". It had German keyboard layout including German special characters (Ä,Ö,Ü,ẞ). The quiz games, the typing lessons and even the built in basic examples had German text. Impressive, given typing lessons are not trivial to localize and most 8 bit computers did not get localized beyond TV standards and power supply. It said "Mister X Basic" instead of "Pre Basic" when starting Basic. I am pretty sure, the German manual did in fact mention multi dimensional arrays. It took me some time to understand that concept at age 11. Even as an 11 year old, I was frustrated because you could not print without waiting for the user to press enter. When I got a Commodore 64, I was shocked that it was actually much slower on some basic tests like adding up 1...1000 using a for loop. Other than that, the C64 was a great upgrade, obviously.

In the mid-late 1990s we had a PreComputer Power Pad which seemed to have an enhanced LCD (with four lines, I believe) and built-in BASIC. It seemed similar to this one, but I seem to recall that CHR$() indeed accepted values up to 255 and actually had “hidden” characters that were not mentioned in the manual. PRINT would still pause after each line, but perhaps it was less restrictive because I remember being able to repeatedly print a single line at a time without a pause by using a loop that cleared the screen (CLS) followed by a PRINT with a suffixed semicolon and then creating an appropriate time delay; it doesn't look like that would have worked on the machine in this video. Interestingly, the Power Pad's parser recognized commands like LOAD but always immediately responded with “?DISK ERROR” or something similar, and I don't believe this feature was actually implemented, though I could be wrong. The model did advertise an add-on cartridge for saving BASIC programs or expanding its memory, but I never had one so I don't know exactly how it worked. Without a cartridge, the Power Pad was at least capable of remembering the last BASIC program entered when powered off as long as the batteries were not removed, though.

That keyboard looks pretty sweet. Might be worth getting just for that.

I had this as a kid and this little computer was the reason i got into programming. Love that video!

The Pre-Computer 1000 was my introduction to computers and programming. I still have mine somewhere, but I think the LCD went out on it. I need to dig it out and see if I can repair it. If I remember correctly you could purchase expansion carts, one of which was used solely to save BASIC programs you had written.

The explanation of BASIC dialects in the manual is hilarious! 😂😂😂

Before it goes under in a subthread here, the machine is emulated in MAME, the ROMs are easily available and from what i can gather when looking at the example programs inside the ROM it uses different tokens than the C64s one but this smells so like MSBASIC... In the ROM i have, 27-00780-002-002.u4, the BASIC examples start at 0x17000. And the interpreter seems to start at 0x3800 on first glance. And looking at the token list starting at 0x5650 they took the lazy route with removing commands and just zeroed them out. 🤣

Wow, to think that this was recommended to me and yet, I had this model computer when I was a young child. This is one heck of a trip down memory lane, although I never used it to its true capability.

Robin don't worry about the stomping noises on your video. I also have elephants living upstairs in my house.

I really appreciate the effort put into this!

I had a foldable pocket computer from RadioShack when I was in college. I forgot the model. It had a few lines of text and a great keyboard. It had BASIC that's why I bought it. The good old days.

Interesting video. Would have been awesome if they had included a Tape and Video connector, even if it was a small expansion cart to add the functionality.

Some more constructs related to (portable) BASIC-80 variants to check (from the TRS-80 Model 100 and the NEC PC-8201A): VARPTR() and HIMEM system variable (Model 100), cursor positioning with either PRINT@ (Modell 100) or LOCATE (NEC), CALL [, A [, HL] ] (Model 100) or EXEC (NEC), OUT Z-80 port command, INP Z-80 port command, VT-52-style ANSI escapes with PRINT. Also: DEFDBL, DEFINT, DEFSNG, DEFSTR (define var-list as specified format w/o suffix) ERROR n, ERRL, ERR (simulate error #n, last error line, error number) FIX() (format number to fixed) POWER n, POWER CONT, POWER OFF, RESUME (power management) INKEY$ (system var instead of GET) KEY, KEY LIST, KEY ON/OFF/STOP (related to keyboard shortcuts) Some may be fun. E.g., if OUT and INP work, you should be able to hack the LCD (if you can reverse engineer to what ports the LCD drivers connect to and what the layout and the protocol is - if there is a datasheet for the driver chips, this may be doable). If INKEY$ is present, this should allow for for some arcade action. If not, but INP is, you may be able to read the keyboard by this, if the keyboard is read via the Z-80 port (which is a probable solution for a Z-80 system).

The more I see of this Pre-Computer, the more I'm convinced I would have loved the thing as a kid. I'm still glad I was fortunate enough to get a C64 when I did, but this would have definitely been a nice precursor to that if the timing had allowed it.

I enjoyed this video a lot more than I have any reason too. I always wanted a VTech Computer as a kid, but than at Age 6 or 7 I got a Atari 130XE and learned programming on that machine. Its such a pity: My daughter enjoys all comforts of having access to modern technology, but nothing comes close to the simplicity of this old tech and the fealing I had back than when I finally got a program to work. Anyway: Thank you Robin for this exploration!

The ROM has already been dumped and there's a preliminary driver for it in MAME, labeled pc1000.

Vtech licenced Microsoft Basic for the Laser128 (Apple II clone), released in 1986. I think, they were clever and licenced it for all their computers, or they now had a working relation with MS and were able to acquire more licences.

That was an amazing product for the time and the price!

Could L3 be "Advanced Feature", and a sign of this being specifically TRS-80 BASIC?

I had a thought: there were some legal and illegal TRS-80 clones coming out of Taiwan and similar places in the 1980s (just as there were Apple 2 clones, including ones made by VTech) that had pirated Radio Shack/Microsoft BASICs, maybe it's derived from one of those, so it's a derivative of a derivative? I don't recall VTech making a TRS-80 clone but they could've grabbed the BASIC from someone else local.

Excellent investigation!! I'm sure DJ could modify this computer to have a larger screen. Even modify the ROM. Thanks for sharing

I have always been curious about these. 😜

I am surprised that the keyboard keys are shaped so well. Kind of Apple IIgs like and very rare for many computers of the 80's.

I learned programming on this thing. When I got a 086 I realized I can use those instructions for GWBasic,

At 25:11, did you also try DEFFNA(X)=2*X (without the spaces)? I recall MS BASIC variants sometimes being picky about these things, and maybe if the designers of this computer did not intend to remove the possibility for user defined functions, it could be that the BASIC dialect is somewhat different and parses the DEF FN ...() and the FN ..() slightly differently and maybe removing the spaces will work. In general, many BASIC variants don't care about whitespace, but some do, and some do in very odd circumstances.

The L3 error at 25:02, a call to a feature not supported in the L2 ROM was made. On the TRS-80 MI/III disk basic not only extended the keyword table, it also added support for L3 functions and keywords present in the ROMs.

wounder if i still have my old vtech precomputer 1000 board (i removed it and put a raspi in the case)

Interesting, 65529 is the max allowed line number in the MS Basic in the Spectravideo 318/328 too. Why do I still remember that… 😂

65529 is a weird maximum line number - I have to wonder why they don't support the full 16-bit range (i.e. up to 65535). Perhaps those last few values are reserved by the interpreter for some reason...

You put it through its paces! I'd be curious if a ROM dump would potentially show anything else. edit: after reading the comments: it's already been dumped, and yes, lol.

If I knew it had all this capability when I had one back in I was a kid I would did more then just treat it has a typewriter. I could of learned how to use basic and more. but had no manual so who knew this at all not me. thanks for the video and showing what this thing can do

Nice little machine, but without a save feature and that one line screen size I dunno.. my dad owned one of the Radio Shack hand held ones you mentioned. I would think that at LEAST a basic cassette save feature, like how the first TRS-80s done it would be minimal. I recall learning to program on the TRS-80 model 2, loved the BASIC it had with the PRINT@ feature and special character graphics.

When I was a kid, me and my friend dreamed about computers like this.

On a freshly started Commodore 64 we get the same responses as if the variables had already been cleared ("string too long," 89, 255, "1 2 3... 88").

Robot Korben Dallas: "Listen, lady, I only speak two languages: Microsoft BASIC and bad Microsoft BASIC."

On other Microsoft BASICs, there must be no space between the FN and the function name as you did with FN A(20). 10 DEF FNA(X)=10*X 20 PRINT FNA(20)

If this uses one of the common LCD modules using the HD44780 or similar, the limits on CHR$() might have been there to limit use to the alphanumeric and more common symbols. Perhaps they thought that the symbols outside that range would be confusing, since it would be mostly less common symbols and characters not used in English, the 0-15 would be the 8 user defined characters repeated twice, I believe,

A poke, a poke, my kingdom for a poke!

Retro computing comedy gold @16:04 😅😂😊

It would be cool to look for typical microsoft code or even easter eggs in the rom. But without a PEEK command that will require examining a ROM dump, if those even exist.

Watching someone programming on a 20 character display is like a meme. There's definitely more telling than showing.

Interesting that going above the line number limit returns a syntax error instead of an illegal-quantity error.

It is extremely reminiscent of the Pocket Computer Basic implementations that Sharp and Casio used on their machines.

It handles RND just like Atari BASIC. Along those lines, have you checked for a VER command to show version information?

I had one as a kid. I had the dictionary package on it. I recall it was pretty battery hungry on road trips.

Would be cool to see a serial out mod and have this run into a terminal display.

On the topic of the hash/number-sign character at 23:22, I learned from Jim Buitterfield's popular ML book that this is formally called an "octothorpe"; he uses the word a couple of times in his book and also puts the definition in the book's glossary. I suppose he wanted to communicate accurately!

Theres a lot of comments about TRS-80 Basic. Tandy corp had discontinued the TRS-80 a decade earlier and were selling v-tech by the time this went into dev. I would imagine Tandy's MS Basic80 license held little value by about ~91, but having a pre-puter to sell did hold some value. I doubt v-tech even had to pay!

commercial flash did not exist in the 80s. The only reasonable storage cartridge would be a high voltage PROM or a battery backed RAM. There was UV erasable, but that require a UV bulb box as an accessory. Maybe an Intel bubble memory cartridge?

God damn it, now I want to add this thing to my "collection".

Be interesting to see if an LCD guru out their invents a 4 to 5 line display mod for this thing, maybe its limited in its functionality or what it can do.

ok BS error is pretty funny. Reminds me of the AMD Ryzen 1600 AF. lol I saw probably 4 reviews of it. Not one of them was able to review it without laughing. lol

My fourth-grade classroom had the successor to the PC1000, called the PC2000.

I used to have this as a kid. But we didn't have the manual!!!!! So the programming mode was absolutely useless to us. But I guess the full-size qwerty keyboard did make me feel more grown up. The Speak & Spell was a baby's toy by comparison... although its VFC display was cooler-looking (a pity they died out - an unfortunate casualty of technological progress).

I got one for $10 on ebay and first off the size didn’t translate in the video it’s nearly as big as an apple iic but pretty light even with batteries. I had had a lot of fun with it already just playing the games but it needs to be cleaned. I am surprised how much fun I had with it.

Much better vocals in the end credits this time than we're used to. I actually made it to the final second. Who is the artiste?

I was hoping for a ROM dump, but this method also was interesting. But you should take it apart now and look into the hardware just for fun.

Im kind of getting into Python language its neat how that also you can also calculate numbers etc.

Robin, while I appreciate your forensic skills, let me ask the most important question: Are we gonna get a Christmas song family video this year?

It could be a Microsoft Basic. But I'm sure in Hong Kong in the 1980s they didn't particularly care about acknowledging copyrights. Vtech was the company that made TRS-80 and Apple 2 knock-offs.

The error codes are very similar to my TRS-80 with level II basic.

Remember that VTech was making the laser 128 Apple 2 knockoffs in 1986, just before this came out. Thus, they already had an implementation of Apple compatible Basic in the ROMs for that machine. I would guess that this is a modified version of that work. The Laser 128 survived court challenges over its ROMs from Apple, essentially proving that they likely coded it themselves, which would then require no licensing or acknowledgment of any kind. It would literally be VTech Basic.

"And you have to just 'BASIC'ally reboot it again..." 1. Haha, nice pun! 2. "And you have to just 'BASIC'ally reboot it" (period).

will that computer or basic use the Play command to play music like the C128 and the Mega65?

I highly suspect something of that sort given that there are bits of text in there that suggest keywords for functionality that's absent. And I want to say there was text similar to the initial BASIC print out that doesn't match the name.

This is so similar to CoCo BASIC in so many ways it makes me think that PRINT FNA(20) would work with your DEF FN statement. But who knows? There are sooo many flavors of BASIC.

Didn’t Vtech makes some DOS and Apple compatible products under the Laser brand? Maybe they already had MS BASIC license from those products?

It could be that they had a microsoft basic system and coded to make theirs just like it without actually having the source code. It wouldn't exactly be a cleanroom design because they could try out stuff and compare. It may be that the variable type suffixes are different than what you expect them to be in a few cases. The internal floating point representation is not going to be IEEE. It may be one of the many libraries that were on the market in the past. I saw a BASIC from back before Microsoft that did two letter variable names but it also allowed a digit as a 3rd character. It however didn't just ignore the 3rd letter. It used a rule that anything with 3 letters must be a keyword. "PRIZZZ" worked fine for "PRINT". "LET A=1 NEXT" would get processed as though it was two statements.

I inherited a database from my predecessor. It was made in microsoft access. It was moved over to mysql (but they had the ability to move it back and forth with access) and a PHP web app was built on top of it. Anyway......I thought it was odd that any checkboxes in access that were checked had a -1 in the database as the actual value. I believe even today over 10 years later I never eliminated that completely. All newly checked checkboxes return a 1 not a -1. But I think I left that alone in the database. The access version may still exist, but it's completely incompatible these days. I've never had an explanation until now. come to think of it, all 0's = 0, but all 1's = -1. So I guess that makes sense.

VTech hacked and mangled the ROMs in the Laser200/300. Arguably they were originally TRS-80 MII or MIII L2 ROMs. Lots of no-ops to remove functionality such as some cursor positioning characters and keywords simply being rewritten. I have a vague memory of SOUND and ERROR or ON being an example allowing odd syntaxes such as ON SOUND GOTO 10 for an error handler - may not be fully correct recollection. It wouldn't surprise me if the PEEK and POKE code is still in there just the keywords are reused for something else or just blanked from the keyword table.

Hiya Robin.

my older brother had one and i played on it

It's very similar to the Laser 50, another one-line computer toy from VTech. Unfortunately there is no PEEK() so it's not possible to dump the ROM in a easy way. If we have the ROM then it could be emulated

What’s the goth outro music? I love it.

The error format (e.g.: ?SN Error) is typical from Microsoft BASIC.

Someone needs to hack this bad boy to use a larger screen or connect to a terminal Yeah, it's probably using something simlar to the TRS / Sharp PC-1 though PC-4 one line LCD pocket computers. Fairly robust considering what they had to squeeze it into.

Might be similar to the version on the creativision console???

i was wondering if you could use PEEK to try to find some signs of guilt in the basic program itself

If the ROMs in the machine are in standard packages and not blob-top bare chips on the board, they ought to be possible to unsolder and read. And maybe even run under emulation, by adapting an existing open-source emulator of a Z-80-based machine ..... Otherwise, if the processor is in a standard package, remove it, use an Arduino Mega to impose values on the address bus and try to read the memory that way. You might need to trick any bank switching stuff. Not much else I can say without motherboard pics .....

does it have the SOUND command ? e.g. SOUND 5,1 (note, duration)

But can you expand the memory to 64KB? :)

Oh, I just thought of something! Do you have any videos of natively BASIC computer (but my faves are Commodores, since that's what I grew up on': PET, 64, 128, and we own 64 and 128) adding program lines without just loading something from storage? How would you tell a BASIC program to add to itself just by running? While we're at it, how would you do the same in assembly and byte-by-byte ML? What would happen if you could tell a BASIC program to add a line number that exceeds that limit? Just get "Syntax error in [x]" (whatever line number tried to add one above that limit)? Anyway, even if you can now just tell me that I'm right, I'd still love to watch you demonstrate how to make a program write more of itself! I saw that someone wrote some self-modifying code but that was in something like C and I didn't understand it. I'd love to see it done in BASIC and 6502 assembly (I'm not that familiar with assembly but I do think that some of your videos have helped me understand it a little). Also, do you know C, and if so, will you please try it in C and explain it?

What is the song in the credits? It reminds me of Ladytron - High Rise :)

it's not just it needs to load and save, it needs a bigger screen. I still think 1 line is useless for anything past a toy. I mean even 4 lines would be pushing it. oh and muting (or eliminating) the speaker would also be nice.

so 00 is (FF in hex)?

My sister had one

Why did you put "maximum value" in quotes, as if that's only figurative instead of actual?

I noticed you never tried to print out any values in immediate mode. Is that not supported? And you used the EDIT command without examining just how that worked. BTW, there was a 6-digit version of MS 6502 BASIC (as used in Ohio Scientific's C1P/Superboard II). It used those two-letter error codes too (although the second letter got changed to a graphic character).

Ah, interesting that it's a patched TRS-80 BASIC, as that explains the ?L3 error. This was meant to mean "Level-3", that is, one up from Level-2, but instead it was just called Disk Basic. ?fre("") should show you how much string space there is (?OS error meant "out of string space"). Perhaps user-defined functions work if you don't leave a space between FN and the variable name (ie, print FNA(10) etc). Later versions of BASIC enforced spaced between keywords.

Wait ! You said you borrowed this from D.J. ? You'd better check to be sure there isn't a Raspberry Pi inside emulating a Vtech. 😜

Looks similar to MSX Basic

I used to see these for sale and assumed they were overpriced tiger electronics handheld type of garbage, this is well above what I expected.

2:02 Which is it, "Zee-80" or "Zed-80"? 4:31 Why is it that Commodore BASIC doesn't allow line numbers up to 65535? 7:04 The heap would need to be more than 25 bytes, since the computation of A$=" 1 2 3 4 5 6 7 8 9 10"+" 11" would need at least 21+3+24 bytes to succeed. But, this still bizarrely small. Oh, you have to statically reserve string space. 15:06 Odd that their built-in calculator appears to have double-precision support. It also seems like a poor choice for BASIC-80 that people's expensive computers would have less precision than a simple pocket calculator. 18:30 What does RND(1) return?

Did you test INKEY$?

I remember this thing. It has a surprisingly good keyboard, but like literally no display. Absurd.

Don't give me a BS error. All of my BS is correct.

My impulse control failed, so I got one of these! Dear god, I feel bad for everyone back then. This keyboard is ASS. It's spongy, but fatally even after cleaning it binds so much. My right wrist is starting to ache just from typing on this thing (fricken... any% speedrun carpel tunnel...) I'm going to have to see if adding lubricant to the sliders help, as it's just bare plastic on plastic. You gen x/y people deserved better!

BS error funny I always wondered what the % stood for (integers) learned something new

BS Error 😆