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Any info on Video Technology Laser 500 computer?


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#26 Seob OFFLINE  

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Posted Fri Jan 13, 2012 2:40 PM

Did find some more sites with info or picture on the laser 2001:
http://www.zock.com/..._Laser2001.HTML

http://starringtheco...puter.php?c=206

http://www.classic-c...ch-creativision

http://classictech.w....com/tag/vtech/

http://hup.hu/node/108811

http://www.museo8bits.com/laser201.htm

http://www.pelikonep...=DESC&wrongVer=

#27 carlsson OFFLINE  

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Posted Fri Jan 13, 2012 5:02 PM

Yup. I've seen all but the Hungarian one before. As for pictures, I could take as many as I want... I'm still looking for English docs, but will some day try to merge the German and Finnish manuals into one document, perhaps running it against all the Wizzdom in the Creativision newsletters although I think most of the memory addresses mentioned in those are exclusive to Creativision Basic.

The Classictech blog obviously has false information. The 2001 neither has 80K RAM, chicklet keyboard, four voice sound (SN76489 IIRC) nor is Apple II compatible.

#28 nippur72 OFFLINE  

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Posted Sat Jan 14, 2012 6:21 AM

Talking of Laser 500 video chip, I remember once I did a memory scan looking for character-fonts (a la commodore) but found anything in the addressable RAM. Indeed there was no way to display text when using graphics mode (other than using custom fonts). To overcome this, a developer wrote a basic soubroutine made of DRAW basic commands that reproduced the original font set. The subroutine was later incorporated in almost all programs (games) and the slow drawing of text became a peculiar thing to laser 500. I mean, when a game started, it had to slowly DRAW text like "SCORE:" "LIVES:" (and later of course "GAME OVER").

#29 Seob OFFLINE  

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Posted Mon Jan 16, 2012 4:17 PM

At least i´m happy that the 2001 has come to a real collector that is using it. Since i´m more into console collecting and gaming, it only was booted up a few times. Never played a game on it since i didn´t have a datarecorder.

#30 31336haxx0r OFFLINE  

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Posted Wed Jan 18, 2012 2:45 PM

@carlsson: if you like, I could help you with the translation of the German manual.


@nippur72: NICE! Another Laser 500 user! How did that disk drive work? Just plug it in and the computer will boot it? Is the Laser 500 fully compatible with CP/M?

Edited by 31336haxx0r, Wed Jan 18, 2012 2:45 PM.


#31 nippur72 OFFLINE  

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Posted Thu Jan 19, 2012 11:49 AM

NICE! Another Laser 500 user! How did that disk drive work? Just plug it in and the computer will boot it? Is the Laser 500 fully compatible with CP/M?


the disk drive was attached to a huge cartridge via an IDE-like cable, and the cartridge itself connected on the rear of the computer in the expansion slot. When the cartridge was connected the basic instruction set was extended with commands like "DIR", "DLOAD", "DSAVE, "DINIT" (or was it BSAVE ? I don't remember well, it was 25 years ago!).

Diskettes were single-sided and stored around 170K on each side (again, If I remember well).

As for CP/M, there was a special disk that booted the system. At the time we didn't know what CP/M was, and the only thing we did with it was "DIR". There was a 80-column white on black screen, command prompt and 8 character file names with 3 char extension. Another thing that I remember is that the CP/M disk was not readable when the system booted in normal mode (with VTech disk firmware), perhaps because it was formatted differently.

I think I still have one or two numbers of our club magazine, one with the disk drive depicted on the cover. If I find it, I'll post a picture.

#32 nippur72 OFFLINE  

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Posted Fri Jan 20, 2012 2:48 AM

Ok here some pics (sorry I don't have a scanner, I've done them with my android phone):

This is Laser 500 disk drive FD100A, cover of the Laser Computer Club magazine (ITALY) December 1986:
Posted Image


This is a brief magazine article explaining the basic VTech "DOS" commands (not CPM)
Posted Image


These are the "commercial" games sold on tape, on the rear cover of the magazine:
Posted Image


And last, a simple snake-like basic game written by me and a friend (both aged 14):
Posted Image

I smile as I look at the code and remember. Line 500:

IF G=3 THEN IF M<Z THEN ... :D

(it could be seen as a Demorgan Law application, but at the time I didn't know of it)

Also notice the big amount of data from line 6081: we had no direct way of displaying bitmaps when in graphic mode, so I put codes into data statements and plotted pixels one by one. It was extremely slow!

Unfortunately the documentation on the machine was scarce and rare (mostly written in german), and we managed to write machine language routines only at the end of the laser 500 age.

Edited by nippur72, Fri Jan 20, 2012 2:50 AM.


#33 JamesD OFFLINE  

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Posted Fri Jan 20, 2012 5:47 PM

Just looking at the BASIC...
TEXT 40
BLOAD
BRUN
ELSE
COLOR

I couldn't find a single BASIC that has all of those on a Z80 around 1985.
I'm wondering if they licensed and upgraded a basic or just continued to modify the basic from the TRS-80.

Maybe a CP/M version?

If you couldn't just POKE to screen memory you probably had to write through the VDP.
The Laser 2001 had VPEEK and VPOKE... maybe those were undocumented commands?
I can't find anything that quite matches the specs for the graphics.

#34 nippur72 OFFLINE  

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Posted Sat Jan 21, 2012 3:50 AM

The reason why the Laser 500 appears so "advanced" respect to other Z80s is that it appeared quite late in the 8-bit age. Commodore was already selling the amigas when I had chance to get a Laser 500 in the computer club (though the bootup screen colors make me think they made it to compete with C64).

Having used both old and new Z80 VTech lines (110/210/310 and 500) my guess is that they build the L500 on the specs of the old machines, putting a better video chip and an improved BASIC.

#35 31336haxx0r OFFLINE  

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Posted Sun Jan 22, 2012 8:20 AM

Holy cow, this is pure awesomeness! Thanks for the pictures! IIRC VTech used a Microsoft Basic type BASIC that had some nice commands they probably implemented by themselves.

#36 JamesD OFFLINE  

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Posted Sun Jan 22, 2012 3:22 PM

Holy cow, this is pure awesomeness! Thanks for the pictures! IIRC VTech used a Microsoft Basic type BASIC that had some nice commands they probably implemented by themselves.

I looked through the M.E.S.S. ROM dump I found online. The BASIC keywords have the last character of each keyword ORed with 128 (sets the most significant bit which is not used by ASCII text characters). This takes less room that zero terminated strings. The first character of each keyword is also encoded but I haven't taken the time to figure out how.

The BASIC appears to be pretty good from the look of the keyword table. You can define integers, single/double precision floating point, it supports WHILE/WEND, and it even seems to have a built in assembler.
<edit> Perhaps a disassembler or monitor?
Graphics and sound commands appear to be pretty minimal though.
There doesn't appear to be a VPOKE command which makes sense or someone would have used it.

If you want to have a look at the keywords, they start at $1C1C or 7196 in the ROM. The ROM takes up 32K but I don't know if it is paged.
This program will print keywords without the first character since I don't know how it's encoded yet. It could be shorter but it was quick and dirty.
10 A=7196 : REM START ADDRESS $1C1C
20 B=PEEK(A)
30 REM SKIP FIRST CHARACTER OF KEYWORD FOR NOW
40 REM
50 REM PRINT CHR$(B);
60 A=A+1
70 B=PEEK(A)
80 IF B>127 THEN 110
90 PRINT CHR$(B);
100 GOTO 60
110 B=(B AND 127)
120 PRINT CHR$(B)
130 A=A+1
140 IF A < 7851 THEN 20

Edited by JamesD, Sun Jan 22, 2012 3:46 PM.


#37 31336haxx0r OFFLINE  

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Posted Sun Jan 22, 2012 3:51 PM

I should type in that program when I'ma fire ma Laser up again LOL. That's ingenious to use the MSB as a terminator to save space. I wouldn't have thought about that in the first place and neither in the second place.
Maybe they inverted the first characters?

#38 JamesD OFFLINE  

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Posted Sun Jan 22, 2012 3:58 PM

I should type in that program when I'ma fire ma Laser up again LOL. That's ingenious to use the MSB as a terminator to save space. I wouldn't have thought about that in the first place and neither in the second place.
Maybe they inverted the first characters?

If I were to guess, the first character has something to do with the token since the same letter is different from one keyword to the next even though they may start with the same first character.
<edit>
Using the MSB is very clever, most BASICs I've looked at do that.
Instead of loading the next char and checking for zero, test for negative.

Edited by JamesD, Sun Jan 22, 2012 4:02 PM.


#39 JamesD OFFLINE  

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Posted Sun Jan 22, 2012 4:29 PM

I too cannot believe they developed a whole freaking video chip from scratch. An address decoder chip, okay. But not a video chip. Let's have a look at the graphic modes:
<...>
Given that the Laser 100/110/VZ200/300 (which are TRS-80 Model 1 clones) used the 6847 like the TRS-80 Color Computer, I assume it's their derivative of a 6545/6845/6847.

The Z80 as well as the 8088/8086 are descendants of the 8080. All of those processors use a design that employs "ports" and apparently there is a CP/M80 disk for this computer. Hmm....

While the color palettes of the Laser 500 and CGA may look very close, I don't believe it means they have the same chip.
The 6847 only has 9 colors and none of those modes.
The 6845 pretty much just generates all the required timing signals to drive a display (hence the name CRT Controller).
External hardware has to generate the pixels themselves.
The 6545 appears to be similar to the 6845.
I suppose the 6845 could generate the lower res modes by doubling the output of each pixel, but the 6845 should be easy to duplicate by that time.

As for CP/M, the computer probably has the ability to replace the ROM with RAM and they just wrote some drivers.
I'm very curious how they did the video display, whether it's RAM is paged or accessed through ports.

The colors probably have to do with bits of color resolution and intensity.

Edited by JamesD, Sun Jan 22, 2012 4:31 PM.


#40 nippur72 OFFLINE  

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Posted Mon Jan 23, 2012 2:38 AM

I'm very curious how they did the video display, whether it's RAM is paged or accessed through ports.


what I remember is that graphic rows were not continuous in the RAM, e.g. the second line was not after the first line (in the RAM area) but there was a schema we were not fully able to understand, due to our poor knowledge. I vaguely remember at the end we solved by having a table. I also vaguely remember of OUT cpu istructions, meaning some access thru ports. Such complexity forced us to stay mostly with BASIC programs. Even commercial software (from the pictures above) was arranged so that "sprites" were always on an plain background, in order to simplify the machine language sprite management code.

Nonetheless working with the colour graphic mode (160x200x16) was a big fun because it was color-unclashed! Total freedom.

#41 carlsson OFFLINE  

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Posted Fri Apr 20, 2012 7:37 AM

Since a couple of months ago, I'm having a Laser 500 in a carrying case waiting for me to pick it up.

In the mean time, I found a gallery of pictures of a Salora Manager.
http://img810.images...g/img3676f.jpg/

I took some pics of the inside of my Laser 2001 but never posted them. However I can assure you it looks just as messy, if not worse than the Salora does.

#42 31336haxx0r OFFLINE  

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Posted Fri Apr 20, 2012 11:24 AM

They look indeed somewhat messy. Like a semiprofessional build. It's interesting that the disk drive has almost no logic inside. It looks like all disk drive handling and data de- and encoding happens inside the computer or some kind of external box.

#43 carlsson OFFLINE  

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Posted Fri Apr 20, 2012 12:54 PM

Weren't most floppy drives dumb, with the exception of the Commodore and possible Atari ones? I know e.g. a Beeb floppy drive is the same as in a PC, and in that case you have the floppy drive controller (8271 or 1770) and more inside the computer. However I think in the Laser/Salora case there is an external FDC box that connects between the computer and drive. Remember the same is true for e.g. TI-99 and a number other "high brand" home computers.

#44 31336haxx0r OFFLINE  

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Posted Fri Apr 20, 2012 1:51 PM

That makes sense.

#45 carlsson OFFLINE  

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Posted Wed Oct 10, 2012 2:27 AM

Since a couple of months ago, I'm having a Laser 500 in a carrying case waiting for me to pick it up.

Well, it took some 8 months or so for the computer to travel 200 km but finally it is here. A brief test shows it powers on, but the picture in in B&W both through RF and composite video. It has an AZERTY keyboard so I suppose it is a SECAM edition. My previous experiences with SECAM have only been through RGB, so perhaps it is perfectly normal that not every monitor can display colour? I only tried a 14" Luxor TV and a 1084. I have many more TV's and monitors to try, including those who happily chew NTSC composite video, but perhaps the ability to display NTSC wouldn't matter to the ability to display SECAM?

#46 nippur72 OFFLINE  

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Posted Wed Oct 10, 2012 8:51 AM

from my Wikipedian knowledge of SECAM, it is perfectly normal that you see a monochromatic image in a PAL monitor because the chroma information is coded differently in the two systems (PAL and SECAM).

Monochrome is good for 80 column mode, just type "TEXT 80" (also available in some of the F-keys).

#47 31336haxx0r OFFLINE  

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Posted Wed Oct 17, 2012 9:52 AM

AFAIK the SECAM Laser has a Scart (aka "Peritel") connector that puts out RGB. You could try that to get colour.

#48 carlsson OFFLINE  

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Posted Thu Nov 1, 2012 2:40 PM

Most of the labels on the back side are missing. I suppose the larger card edge connector is an expansion port, the slightly smaller one is a printer port, the RCA connector in the middle is RF (at least it worked that way), then labeled connectors for cassette and monitor and a piece of possibly removable plastic where it might be room for a SCART connector, but no actual connector.

However I see now that on the bottom side are two toggle switches: Channel 3-4 and B/W-C. The latter is currently set to B/W, so I should experiment with switching it to colour mode and see if I indeed get a colour picture... and yes, I did! Blue screen and light blue border, looks like a Commodore 64 with different font.

Posted Image

Actually this specimen comes with a Dutch (!) course in Basic tailored for the Laser 500. Quite surprising combination of AZERTY + Dutch, unless it was meant for bi-lingual Belgian users, those who do both French and Flemish?

Another observation is that with composite video on a 1084, I think the 80 column mode almost is more crisp and clear than 40 column mode is. I find that rather odd.

Edited by carlsson, Thu Nov 1, 2012 3:10 PM.


#49 Seob OFFLINE  

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Posted Thu Nov 1, 2012 2:58 PM

In the Netherlands we use qwerty keyboard, us style, sometimes special qwerty keyboard with specific dutch letters.

#50 carlsson OFFLINE  

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Posted Thu Nov 1, 2012 3:22 PM

Of course the computer, leather case and folder with instructions might have come from different sources and put together at a later point in time.




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